Now Cutting! - Auckland NZ

[litemover]

Hi Everyone,

Thanks for all your help in helping me to decide to go with the Mechmate open source router. I decided on this one because it is really a no brainer to go with based on the performance and reliability of the machine as compared to aluminum one's with deflection problems.

Anyhoo, I do have a bit of a dilemma that I could use help with. I will be needing to order electronics, and anything I can stuff onto an airplane masquerading as a golf kit of bike kit, etc.. In other words, I will have enough space to bring from america all the parts that I can, which would fit in a golf or ski, even kayak sports case, up to 40kg. maybe 45. I am wanting to bring anything expensive or hard to get a hold of. In the country I live in, most electronics are quite expensive in comparison to America. So any recommendations would be fantastic .

Also, what sort of router bits should I bring with me? Will be doing quite a bit of cutting of plywood, MDF, aluminum, acrylics, and polycarbonates. Also relief sculptural MDF stuff, and wood. Can anyone recommend some premium bits that don't wear that fast. I travel back and forth from America quite frequently, and would prefer to buy my parts in America as much as possible.

Many thanks,
Chris

[litemover]

Hi, just wondering, how heavy and how large is the parts kit?

Thanks,
Chris

[MetalHead]

I can ship to you. You need to get a freight forwarding company. I may be able to help with that.

I can also ship you the electronics control box parts as well. I can pack each pretty good and also put them in wooden crates. Each weighs about 100 lbs if you get them packed good. I can't recall the weight limit but if needed we can split it all out over 3 boxes. But for estimates on freight figure on the max weight the carry will ship and these boxe sizes.

29x19x8 - Laser Parts Kit
22x22x12 - Control Box Kit

Also if your coming to the states, I can ship the stuff to your states address each time you come.

[litemover]

I can ship to you. You need to get a freight forwarding company. I may be able to help with that.

I can also ship you the electronics control box parts as well. I can pack each pretty good and also put them in wooden crates. Each weighs about 100 lbs if you get them packed good. I can't recall the weight limit but if needed we can split it all out over 3 boxes. But for estimates on freight figure on the max weight the carry will ship and these boxe sizes.

29x19x8 - Laser Parts Kit
22x22x12 - Control Box Kit

Also if your coming to the states, I can ship the stuff to your states address each time you come.

Ok, great, thank you. That may work. I think if I at least order the parts that would be impossible to get done there, I'd be in good shape. Shipping costs a fortune from here to there though, and 200 lbs might be fairly pricey.

Would it be possible to just purchase the laser cut parts that require bending, and then get the rest shipped cut there?

Many thanks again for the help,
Chris

[MetalHead]

In the end it would still probably be cheaper to ship you all the parts after you get a "one off" price and the time and effort needed to find someone who will do that small of an order.

[darren salyer]

The parts I've gottten from Mike have all been top notch.
I'd be leery of buying the first set a new vendor attempts to produce as a one off.

[litemover]

In the end it would still probably be cheaper to ship you all the parts after you get a "one off" price and the time and effort needed to find someone who will do that small of an order.

Ok, sounds good. Probably right. Is there a price list somewhere?

Thanks,
Chris

[litemover]

Was just wondering about attaching a laser head to one of these. Has anyone done this yet? Seems like it would be entirely possible.

Chris

[litemover]

Is there any benefit to going with the G213V from Gecko?

They say they are configurable in steps. Also, will the new gecko with a motion controller in it be any good to use with mechmate?

Thanks,
Chris

[danilom]

For cutting it would be possible but not for engraving, as you need a lot more of speed and acceleration for that.

[danilom]

You can do it any way you want. If you see that someone posted using something than its possible. If you don't then its up to you to try that.

We all run our drives in 1/10 microstep, its because that is smallest microstep resolution bigger than the motor positional error. All geckos work 10microsteps, this G213V has a switch to adjust it. You could use it but only if you need 1/5 or half stepping to gain more speed at same mach3 kernel speed

[litemover]

That would be fantastic for cutting. Especially as an alternative to router for smooth edged detail work.

[litemover]

Great, thank you.

CC

[danilom]

Just be prepared to pay 1-2 mechmate costs for a nice laser source

[darren salyer]

Have you done any research at all on your own?

[domino11]

Chris,
Try doing a search for things on the forum. A quick search for 213v turned this up. :) Here (http://www.mechmate.com/forums/showthread.php?p=52339&postcount=51) for the answers to your question. Take note particularly of Brad and Mike Richards responses.

Also no need to use quotes if the reply is to a previous post. :) See Using quotes when replying to a post - only use if essential please (http://www.mechmate.com/forums/showthread.php?t=816)

[litemover]

Have you done any research at all on your own?

All I've been doing is research the past couple weeks on this. And really grateful for all your help as I don't have a lot of time left before I have to get back to NZ. I've literally changed my return flight in order to source these parts and buy what I will need in order to build this while in the US. So please excuse me if I am asking a lot of questions that would likely be found after hours of reading through the forum. Kind of up against a deadline before having to fly away.

Advanced electronic parts in New Zealand are very difficult to come by. In most cases, they would just be special ordered from the US, which would cost a fortune in shipping. Since I am a total newbie at building a CNC, I've first had to figure out how it all works, then figure out what pieces I will need to bring back with me from the US.

So again thank you guys for your help.
Cheers,
Chris

[litemover]

You can get a 150W laser tube for $1381.99 on Ebay right now. Might be useful in cutting plastics and acrylics.

http://www.ebay.com/itm/150W-CO2-Laser-Tube-for-Engraver-Cutter-Water-Cool-200-cm-2000-mm-/221037630425?pt=LH_DefaultDomain_0&hash=item3376de93d9#ht_1761wt_791

[Zouave]

What part of the states do you usually travel to?

[litemover]

Great thanks! Very good answers indeed.
Chris

[litemover]

CA, orange county area :) Just hanging out till I figure out what to bring back with me. Seems like I will need:

Drivers
Motors
BOB
Smoothstepper Etnet
Wire
pulleys, cable carrier

Maybe some bearings?

[litemover]

Anyone know which option I should tick when ordering the G203V:
CW/CCW, Standard, or Vacuum?

Thanks,
Chris

[danhamm]

Little bit more to it than that, laser power supply, laser controller, laser software, and the ability to make it go together.

[litemover]

Found a source for what pieces would be needed.

http://cnc-machines.host22.com/lasers-co2.html
and
http://www.buildlog.net/blog/2011/02/buildlog-net-2-x-laser/

With a chinese 150w laser, it may be affordable to do?

Chris

[danilom]

Its a crappy glass tube. Not very precise and durable. You can get around 500 hours of work from that. They only last longer if you don't use them at maximum power.
Thats what all my laser cutter friends say. One got his machine on fire.

Build a machine, mount a cheap router, do some work and get to know your machine. Then upgrade at will and inform us so we can do it too :)

[danilom]

If you read a little bit of a G203V manual or similar stuff, or some posts on this forum
it should be clear that we use Step/Dir signals from Mach3.

The G203V is available in a G203V-Vacuum version as well. This changes the auto current standby to 0% as opposed to 70%, allowing it to operate in a high vacuum environment with minimal heating problems.

The G203V is also available in a G203V-CW/CCW version. This means that rather than taking a step and direction input it takes a CW and CCW input on the step and direction terminals. This is only necessary if your machine outputs CW/CCW signals as opposed to step and direction.

So STANDARD version it is.

[danilom]

If you are in a hurry, and don't know what to buy. Get the complete kit from MetalHead, lasercut parts, electronics, motors, control box etc.
You will get exactly what you need and without loosing weeks to source, ask on forums, and wait for delivery.
My advice.

[darren salyer]

Very good advice, Danilo.

[bradm]

I agree as well, in this case. Think of it this way - even if MetalHead were charging 40% more than he should (which he isn't), you would still come out ahead of either ordering from home, or making a mistake by rushing here. It's a fair deal on proven configurations.

[litemover]

Believe me, I would if shipping to New Zealand from LA weren't so expensive. 200 lbs quote in that size is well over $1500, not including port/duty. I don't have the budget to waste money on shipping steel unfortunately or I would. I will buy the parts for sure from Mike when I return, or even maybe before I leave to put together a US machine. I'm sure they are top notch as everyone has given them aces!

Sorry for being such a nuisance. I do appreciate the help. Thanks a lot for bearing with me here guys.
Chris

[litemover]

Thank you for clarifying that. Very sorry for not reading the manual first.
CC

[litemover]

Hi, I've been reading through all the motor threads and thanks for all the info on them. I'm still having quite a selection difficulty with the motors.

My first choice is to use the PK296A2A-SG7.2 as recommended, then I heard the PK299 - F4.5a with a 4:1 belt drive was cleaner and less backlash. But then I heard that the PK296-F4.5a running bi-polar parallel were just as comparable and delivered 1000ipm. at 1200 oZ of holding tourue. This is a smaller motor but faster curves, less torque at $157 USD.

What I'm looking for is the ability to cut cleanly through plastic, aluminum, and MDF/Wood. With as little sanding as possible required. Can anyone suggest the optimum Oriental Motor config for a 5x10 table running a 4hp 100mm Chinese Spindle please? I have G203V.

Thanks,
Chris

[MetalHead]

Before you order your motors let me price them as well. I am now setup to sell Oriental Motors direct. I can do the PK296-F4.5A for $139.00 each plus shipping. I will be away from my office though next week and not able to ship any stock parts. I will only be able to drop ship. All OM are drop ship items.

[litemover]

Before you order your motors let me price them as well. I am now setup to sell Oriental Motors direct. I can do the PK296-F4.5A for $139.00 each plus shipping. I will be away from my office though next week and not able to ship any stock parts. I will only be able to drop ship. All OM are drop ship items.

Does this mean that any questions I ask about motors, etc, are moderated and moved to this one build thread? Kind of defeats the purpose of having a forum.

[darren salyer]

Seriously???
Exactly how does this defeat having a forum?
Your posts are all in your build thread, instead of spread throughout the forum
Yesterday, you asked the exact same question in two different spots moments apart.

Asking the same question multiple times in different spots will get you an answer no quicker.

Believe me, going back later to reference an answer to a question will be a huge time saver.
Mike is offering to try to save you a few bucks.
Read my build thread, my motor choice and power supply is listed within and I'm very happy with the choices I made.

Enjoy your buld.
Edited to add: You've been asked nicely by two people to refrain from quoting posts in your replies, I'll nicely ask as well.

[litemover]

That's simply untrue, I asked this question in the motors area where it was, before it was moved here, it defeats the purpose by having a communist sensored forum in the place of a free thinking open one., one where ideas are exchanged, experienced shared , and no question is too stupid or boring. You people sure do have a lot of time on your hands to be bothered by some inquisitive newbie's posts dirtying up your perfect forum. I'd appreciate the right to post in any section I see fit without the whining or censorship. Nif this place is too childish to afford me this basic privilege,a dn my posts continue to get moderated into my own thread, I' ll quite happily shitcan this project and do a different one.

[MetalHead]

If you ask all of your questions in your build thread it helps us all keep track and help you with your build. I moved the post trying to keep us all in line with what your working on. So if you would like to chat with me just let me know and I'll give you a call. All we want is for you to have a successful build. You can see with over 100 machines registered that this format works and works well.

[Gerald D]

Chris, that childish tantrum was uncalled for.

This forum has 25 000 registered members. It is a popular reading place because it is relatively easy to read. You have decided it is your right to spit on the floor of our house. If this were still my forum, I would expect an apology or I would kick you out. Your absence here wouldn't cause a ripple .... in fact it would calm the water.

[Alan_c]

I' ll quite happily shitcan this project and do a different one.

If you decide to build a MechMate, its not for our benefit - it will be for yours. We have built our machines by learning from the forum and from others that walked the path before us - it serves us well. Accusing us of being commies and closed minded will not get you the help you seek, I agree an apology is in order. :mad:

[smreish]

Ditto. (always at least once a year this troll behavior pops up)

Chris. There are many people here, like myself, that dedicate our experience to sharing with the forum on a daily basis since 2005. If you see the folks that are chatting directly here to you hold some of the lowest serial numbers. We are the beta group. We are the voice of experience that have built and watched others build 100+ machines.

If you would like sage advice, it's here.

Please respect the platform here, we all do this to keep it professional, friendly and accessible to all.

[litemover]

Sorry for the frustration folks. It's quite a lot to swallow, especially being in a rush to get the parts. Suddenly not being able to post for help and advice, with exception to this solitary thread of mine, makes the whole project feel quite daunting, sort of being restricted to a small raft in an ocean of unfamiliar territory. To me, this is a considerable investment for not being quite sure of my ability to produce the end product. My lack of confidence has me feeling for the for the walls a bit more than usual. So I apologize for the frustration, and for asking too many questions.

Thank you for the support.
Chris.

[MetalHead]

Well Chris amny feel that way at first and once they do dive in they just do the work in pieces and look up one day and they are cutting :)

[bolingerbe]

Chris, I felt intimidated when I started. But I had read some post "Not enough" but what I found reading the post is if you ask the questions you will have everyone trying their best to help. I have made some changes to my setup by adding a 4th axis, changing the operating voltage of my motors and the addition of a removable sections of my table to allow Vacuum hold down or the Tee slots I original installed. Most if not all of this information is contained in the Forum. Some of the people answering the questions are also found on throw out the web doing the same thing, helping others. Trust me I did not complete my machine without help and every time I asked for assistance someone stepped up and answered the question at hand.

[Zouave]

A lot of us also subscribe to specific threads, including build threads, so get email notifications that you have posted, and can see your question immediately there. Posting a new thread only gets noticed by checking the forums for new threads.
Good luck on your build!

[Gerald D]

A lot of us check last day (http://www.mechmate.com/forums/search.php?do=getdaily&days=1) and it is frustrating to open a "new" post, wait for the whole thread to load, and then see at the bottom it is a duplicate post.

If a particular user becomes irritating, some would put that user on ignore (http://www.mechmate.com/forums/profile.php?do=ignorelist), and make sure time is not wasted with irritations.

[litemover]

Ok no worries. Thanks for the reassurance. Just don't want to start building this and get stuck, which being so far from the US tends to happen with parts especially.

Still just trying to figure out what motors will make the finest cuts that require little sanding, the OM geared, or the ungeared. Anyways, thanks again everyone for the help.
Chris.

[darren salyer]

It is my understanding that the direct drive motors with the belt drive reduction offers the best resolution,but someone may chime in to dispute that.

[KenC]

To be very specific. Direct drive motor with a belt reduction is the most cost effective mean to increase mechanical transmission resolution on top of the electronics means e.g. micro-stepping.
A stock gear box with the right specification will achieve the same performance but the cost is a lot higher.
BTW, even with home made belt reduction, the cost is definitively more than a few dozen of hot dogs, timing belt pulleys don't come cheap especially when you have to make 4 set of them. but will still be cheaper than buying a single OM with 7.2 gearbox.

[litemover]

Thanks Ken,

I'd be happy with whatever option delivers the cleanest cut, which requires least sanding, despite the price, within reason of course.
Chris

[KenC]

"Cleanest cut" is such a general, subjective & illusive goal...

[Gerald D]

In all three groups of users (those with gearboxes, those with belt-drives and those with direct drives) some will get good cut quality and some will get poor cut quality, with swings between good/poor happening from day to day. There is generally consensus that direct drives can be improved by gearboxes/belts. But there is no hard evidence that a belt always beats a gearbox, or vice versa.

[KenC]

And there are those (yours truly) who are too lazy to "upgrade" their direct drive even after 2～3 years...
"You gotta sand anyway..." Is one's excuse...

[litemover]

Thanks.

I think I get it now. One last question, does it hurt performance to have too much torque? In other words, would it be too big to go with an OM 299 vs a 296 OM? Then put a gearbox or belt drive on it? Also, is there any benefit to going with .72 degree or .90 degree motors to get finer edges?

Almost there with motors.
Thanks,
Chris

[Alan_c]

see here: http://www.mechmate.com/forums/showthread.php?t=255

[litemover]

Thanks, I read that one, and was staying away from the larger 1200+ oz motors. But did wonder about them. Really interesting and informative post though.:)

Thanks,
Chris

[Red_boards]

Chris,
I assume that you have decided whether to wire half-coil or bipolar? Because that affects your torque. You must have, because you've decided your power supply, right?
Just thinking...

[Richards]

Chris, let's do some math. A stepper motor driven by a Gecko stepper driver makes 2,000 steps per revolution. Finding how "fine" or "small" each step is, on an ungeared motor is simply knowing the diameter of the spur gear and then dividing that by 2,000.

Common spur gear sizes in the United States are 20-tooth (1" diameter), 25-tooth (1.25" diameter) and 30-tooth (1.5" diameter). So, minimum (finest) per step movement on an ungeared motor would be 0.0015708" for a 20-tooth, 0.0019635" for the 25-tooth, and 0.0023562" for the 30-tooth.

Using a 4:1 belt-drive would reduce that distance by 4X, for a minimum per step movement would be 0.0003927", 0.000490875" and 0.00058905".

Mechanical "wobble" or flexing or "slop" in the machine will keep you from getting that resolution unless everything on your machine is tuned perfectly. A MechMate is much "stiffer" than my Shopbot PRT-Alpha was, but I think that if you ran a CNC router back and forth about 10" several times with dial-indicators on both ends of the travel that you would see several thousandths of an inch variation with each move. That would show you the "repeatability" of the machine.

We all know that wood changes dimensions because of humidity, so cutting multiple parts that have a few thousandths of an inch variation is not a problem because next week or next month, the wood will be a slightly different size anyway.

Metals and plastics are highly resistance to humidity, but they still are affected by temperature. Even the best machinist can't guarantee that a precisely cut piece of metal will have the correct size if that piece of metal is measured at different temperatures.

What I'm trying to say is that you shouldn't just do the math and then expect your cuts to be as "fine" as the math tells you that they will be. Machine "looseness", chip load, cutter flexing and all the other little "gotchas" will affect the quality of your cuts. I was extremely disappointed with the cuts that I got with my Shopbot, especially on curves; however, when I learned that each type of wood seems to have a sweet spot with feeds and speeds and cutters, things improved, i.e., operator inexperience was causing a lot of problems. After I built and installed 3:1 belt-drives on the Shopbot, cut quality improved dramatically. You'll probably find the same thing with your machine. Operator inexperience will give you poorer quality than you expect, but things will get better as you learn and gain experience.

On my best days, I was happy to get cuts where the gap in any joint was less than the thickness of a piece of copy paper (about 0.003"). When that happened, I knew that all the flexing was working in my favor.

Now, to your question about the PK296 vs the PK299. If you're going to add a belt-drive, the PK296 is plenty of motor. If you study the electrical specs on the Oriental Motor website and compare the PK296-03, the PK296-F4.5 and the PK296A2A-SGxx, you'll see that the motors are the same electrically. The F4.5 has eight leads and the other two motors have six leads, so the F4.5 can be wired either half-coil or parallel. The F4.5, with a belt-drive, can be driven harder than the SGxx motor with a gearbox. That's because the gearbox is not as mechanically robust as a belt drive, i.e., if you drive it harder than Oriental Motor recommends, it will wear out sooner than expected.

The Keiling motor that Mike (Metalhead) sells is an excellent motor. I tested one for him a while back and ran it side-by-side on my test bench with a PK296-F4.5, a PK299-F4.5 and a PK296B2A-SG3.6. ALL of the motors were excellent. ALL of the motors (when used with the proper power supply) were more than adequate for a typical CNC machine.

Build your machine. Learn how to use it. Make some money with it and then, after you know exactly what needs improving, you can modify it by adding different motors, linear rails, or anything else that allows you to make the cuts that you need to make.

[litemover]

Wow, thanks for that incredible information Mike. That really helped a lot. No I haven't figured out the half coil thing yet either Red. When the gearbox wears out on the SG7.2 version, is it easily replaced, or does one have to toss the motor out and start from the beginning? Also, can you upgrade the gearbox to a belt drive later (take off the gear box)?

Linear rails/motion bearings sound really good on the Z axis at least. I looked at the carriage design and am not sure I can reproduce the amount of accuracy you guys have on it. We'll see.

Thanks for the info guys.
Chris

[Zouave]

I know it is intimidating, i had the same concerns going in. But the reality is that if you follow the instructions here, and go about it carefully, you will get the same results others have. I want sure going in, and i am really happy with where my build is right now.

[bradm]

Use the half-coil wiring.

The SG7.2 is essentially a single, non-serviceable unit - the motor shaft itself is cut into a helical gear, so you cannot remove the gearbox and use the motor. You can check with OM, but I'm pretty sure you can't replace the gears either.

The Z axis, in the modern six wheel version, with the offset bushings is not difficult to make accurate. Might even be easier to get plumb and square than linear bearing rails, which will only be as accurate as your mounting of them - which you'll have to design.

[smreish]

I will say that I have owned Multicam units with linear slide z axis and my MechMates.
Each require their own little secrets to set up square and true.
By far, because the mass is less on the MM, it is the easier of the two types.

The slides required a lot of m4 m6 hex head cap screws to play with. The MM....6 jam nuts, bur really only 4, because you use the top and bottom to set it all up, then match the middle.

Last time I squared up #28 during it's annual checkup, it took 2 framing squares and socket wrench to reset the plumb in about 15 minutes.

[Zouave]

Brad brings up a really good point. Replacing a geared motor vs replacing a belt drive motor are two very different costs. I think, as far as accuracy goes, you'll get roughly equal results with either one, potentially better with the belt drive.

[darren salyer]

The z axis, while it took me a full day to complete, was no harder than any other part of the machine.
I doubt that using linear rails/motion bearings will result in a noticeable increase in machine accuracy.
Having completed a machine, I can say, every time I thought I had a better idea, I ended up back on the proven path for one reason or another.

[KenC]

Ball Screw + Square linear guide is actually easier than it look; as long as you have a reasonable knee mill at your disposal. I have to get base plate milled.
The difficult part is the cost. It cost me around 600~700US$ to get one built. Still going strong.
The plus side is that mechanical reduction is naturally built in (no worries over weak gas spring & loosing steps when carving texture with big diameter (2") ball nose bits). The down side is you can't move Z-axis by hand when power is down.

[litemover]

All really interesting points. I mean, I really know very little about any of this, but for some reason, linear motion bearings keeps popping up in various conversations I've read, which caused me to question that. But you are right, I should jut try to get the first one finished as it is currently, then maybe alter it later, as it would require a new design altogether.

The gearbox vs belt drive is a tough decision. On one hand, if you go with a gearbox, it seems much easier to complete the machine, plus very accurate from what Ive seen on other people's builds, on the other, the serviceability seems less with a gearbox. The belt reduction seems like it would be higher torque, but maybe accuracy depends on the drive construction?

How frequently do motors go out? Has anyone here had to replace motors on their machine much?

Chris

[riesvantwisk]

Chris,

I dont use my machine to foten (unfortunatly) but i had a motionking (9801) motor going out.it felt stuck... I opened it and cleaned it out, put it back together and voila, it worked perfect again. I dont read much they go out, sometimes do. I have a spare in the shop just in case, also because i am in a country where import is very differcult.

[litemover]

Thanks Ries,

I understand that about import. It's tight in NZ also.

Chris

[litemover]

Hi guys,

I'm back in NZ, and looking to get some laser cut pieces done, and have a vendor. Should I just trace the plans or is there a set of DXF files for me to take to the cutter to get an estimate? They do one off cutting and folding for great rates.

Thanks!
Chris

[litemover]

Going shopping for an enclosure today, and Din rail, wire/cable. Read the posts about the wiring and electronics, very informative stuff. Still not sure about the power supply, but will read that tonight and see what they have at the electronics outfits here in Auckland. Started gutting my old G5 for it's case to install my new Hackintosh, which will be a dual boot PC/Mac OS based off of an Asus Rampage IV Gene board, which is micro-ATX going to the BOB.

Stuffed my shoulder, and received 6 stitches in my head after falling on the rocks out at the beach a few days ago, so waiting for that to heal before I start with the table steel. Hopefully, my arm can move by then and lift some of it (it sounds fairly heavy from what all of you say)

Ciao
Chris

[MetalHead]

So what was the beer to fall height ratio? :)

Just kidding - Hope your better soon !!!

[litemover]

Hey Mike,

No beer, just stepped onto the rocks and had my camera in one hand, backpack on, rocks were wet, so legs just went right out from underneath. Smacked my head on the rocks in an effort to save my lens. Shattered my filters, but lens was ok, so it was worth the 6 stitches:) Was just a trip standing up and seeing everyone freak out about the blood gushing from my skull.

[litemover]

Am I correct in assuming that if I go with the PK296 A2a SG7.2, wiring Full Coil, that my PS voltage would need to be 78.38vDC at 500va? Mh = 6 at bipolar series? Is there a way to build a switch to toggle half or full coil for different uses? Would that even be nessesary?

[Richards]

Wire the motors half-coil and use a PS with 35VDC to 45VDC. The gearbox on the PK296A2A-SG7.2 limits the usable torque, so wiring the motor half-coil still gives you all the torque that the gearbox can handle. The bonus is that your top speed is much higher when you wire the motor half-coil.

The only time that I would wire one of those motors full-coil is if I knew that I would never need more than 100 RPM.

To put it another way, if you use 1.25" pitch diameter spur gears with your rack, a 7.2 geared motor running at 100 RPM would move the axis about 55" per minute. That same motor wired half-coil can go 10X faster, or about 550" per minute. Actual speeds depend on ramping, the load (jogging or cutting), and the pulse generator (Mach 3).

[domino11]

Chris,
Mike Richards has posted quite a few comments on why, with that motor, wiring half coil is better. Lower voltage requirements, and mostly that in that configuration, you will produce more torque than the gearbox is rated for. Unless you have a power supply already at that voltage, I would suggest half coil wiring for that motor.

Mike you beat me to it. :)

[litemover]

Half coil huh? Others here have said full coil is better, but ok I'll do it half coil then. Would be much cheaper on the PS, that's for sure.

Thanks,
Chris

[litemover]

So in Nz we have 230v 50hz, the only toroidals I can find in stock are
50v+50v 500va
50v 50v 300va
40v 40v 300va
Then 18v 18v 300va
Then it goes down to 160va, I can't find a 25v 25v 300va. Any thoughts? Also, should I wire them series being in a 50hz country?
Thanks,
Chris

[KenC]

I'm living in a 230V 50Hz country too, that isn't an issue at all when using tranny built for 60Hz.
Check this (http://newzealand.rs-online.com/web/p/toroidal-transformers/2238853/) out

[litemover]

Awesome Ken, thanks for that link. RS components is huge, and they are in Auckland. I will go there to get the toroidal. I just thought that it needed to be wired in Series for a 50hz country is all. I'll keep on researching it tonight and get out there tomorrow.

Cheers,
Chris

[domino11]

Chris,
Series or parallel has no bearing on the line frequency.

You wire your primary for the line voltage you have, It might be two windings in series or one winding or two windings in parallel, depending on how they built the transformer.

The secondary is wired to give you the voltage and current you need. For the transformer Ken suggested, if you wanted 35VDC you would wire the two secondary windings in parallel to give you 25VAC(35VDC after rectifying and filtering) and you will get double the current of one winding. If you wanted a 50VAC secondary then you would wire the secondaries in series to give you a 50VAC secondary at a current rating of one winding. (You will want the parallel setup for the a2asg7.2)

[litemover]

Thanks Heath,

It all makes sense to me now. All the gist of the motor power threads to me is 32x sqroot of inductance (1.5)= the voltage, but with the PK296A2A-SG7.2 it can be pushed to 4.5 amps just fine without overheating because they are rated lower for some reason? Only need 67% total amperage. The transformer should be 1.4x less before rectifier, as it pushes it 1.4x higher voltage.

Here is the part that is confusing, do Parallel windings on the secondary gives me half the voltage, half amperage, and series gives me twice the voltage, twice the amperage right? I can only wire in series if they are the same correct?

Thanks for the help everyone. It's a great educational process learning how to make your own PS and everything else on this machine. I really love it. Should I regulate the power to smooth the ripples, do I need a breaking resistor on the cap, and last question, is it more preferable to use multiple capacitors to 1 giant one and I bought a rectifier rated at 400v 35a, spade type, is that ok?

Chris

[litemover]

One more question guys, can I use a resistor to lower the voltage if for instance I could only get a 40v transformer?

[danilom]

You need no regulation of power supply, no breaking resistor is needed,
As for the capacitors its really what you can find, usually capacitors bank consists of 2 or 4 pieces to gain 20.000uF .

And no, you can't lower this kind of power with a resistor, for that you would need a really big resistor, or a heater element :)

I must say that I unsubscribed from this thread, my opinion is that these elementary questions have been answered many times before in other threads long time ago. All you should have done to learn the basics of what is what, was to read 5-10 threads.
Look at the pictures, they would say it all. If you don't know what part to get, get the same as everyone else.

[litemover]

I do read the entire sticky section and the top few threads before asking. The fact of the matter is that this site is comprised of many varying opinions of what to do, and how to do it in order to build the same machine. Particularly with motors and electronics. Not everyone agrees, and it's confusing to me. I am sorry to have offended you for needing to understand but unfortunately, I need to understand what I am doing and verifying this prior to just going out and buying the parts that there is conflicting information on.

The confusing part of the electronics is how one can run more voltage through to the motors than what the spreadsheet prescribes (39v max) so it of course becomes a question. Also, the spreadsheet says I'll need 25.000 uf not 20.000uf capacitance. Can I use 2x 10.000 and 1x 5000 without problems?

Very grateful for all the help, I am so very sorry that I am so useless at this.

Chris

[KenC]

Chris,
RS do stock 25,000uf cap , both stud mount & PCB mount.
Yes, you can parallel a whole bank of any number of caps to build up to your desired capacitor value. just make sure the voltage rating is correct.
BTW, all the numbers are reference values, you won't sink New Zealand with 10~20% off.
Honestly, you need a degree in rocket science to understand every single detail of the PSU theory. Sometimes, you gotta just accept & do it.
I agree with Danilo, is nobody use components in question, than you don't need them. If you want to oversize things, oversize as you wish & tell us if that set fire on anything later.
Again, every single question you posted were answered many times over, just keep reading.

[domino11]

Chris,
For your questions,

No regulation needed. It would actually add complexity and more points to fail. (Regulators are also more work. :) )

Breaking Resistor (I am assuming you are referring to a bleed resistor to drain the bank on shutoff) is not needed but can be used. Just leave it off and check the voltage on the bank with a multimeter before servicing.

One large capacitor or two smaller capacitors is fine. I would err on the side of more capacitance. If for example you wanted 20,000uf and you could only get 15,000uf caps, I would go for two 15s.

400V 35A rectifier is perfect. You just need to select a rated voltage higher than what you are running and a current rating at higher than you need. Good choice. :)

Now for the secondary series parallel question,
If you have a transformer with two secondary windings that are the same (same voltage , same current, which is usually the case) if you
1. Wire parallel you get 1xV and 2xA
2. Wire Series you get 2xV and 1xA

[litemover]

Thanks for clearing all that up. Especially about the Xformer amperage, capacitance, and bleed resistor as I'm a bit wary of huge charged caps. So since these are rated at 25mf I ought to get 30mf, that's good to know.

I have an equiss meter, and it was only $20, so I'm checking to make sure it will handle all that ok. . Much appreciated Heath.

[domino11]

Chris,
What capacitance are you shooting for? My 30,000uF was just a number to show a point. I was just trying to show that if you are shooting for x uF and using two caps gives you a little extra going the extra is better than not having enough.

Most multimeters sold today will more than meet most peoples needs. You can find them on sale at big box stores all the time under $20. At least up here in Canada. :)

[litemover]

The spreadsheet says to go with 25000uF. But since I am going to be driving them with slightly more voltage, 40v, I think it is a bit higher.

[KenC]

Again, the numbers are not cast in stone, & you will not go to jail of kill anyone/thing if you don't use exact figure...:D

[domino11]

Chris get a cap or two that give you something in the order of 25,000 to 40,000 uF. That is where I would be aiming. Also make sure the voltage rating of the caps is well over what you are using. Also take into account for line surges and spikes.

[KenC]

60V rated caps is enough but if you feel unsecured, 100V rated cap is only double the price. 400V rated cap are also available, only cost a few times more than 100V caps.
for me, I pick the cheapest cap with the lowest ESR with voltage rating higher than my running condition. Which ended up with a 20,000uf @100V rating. & it happened to be a stud mount... which made me a happy man.

[litemover]

Just a small update, received my laser cut parts from a cutter outside the city at a reasonable price. Everyone in Auckland wanted waay too much. They were cut really well, and bending seems to be good quality with exception of a large bending radii on one of the smaller pieces (spring tension). Hopefully, it won't be too much trouble. The 3mm to 6mm pieces I had cut in G350 steel, as they don't have 300MPa, just G250 and G350. 2mm and 3mm parts were cut in G250, hope that works ok.

http://i46.tinypic.com/21bt384.jpg

I'm looking at used steel for the 67mm crossbeams, have found some used 3m&6m scrap 62mm C Channel for that purpose at $72NZD/$120NZD ea, wondering if that will work ok without compromising the machine stability too much? Steel here is very expensive. 1x 9M 180mm C Channel for main beams costs $580.00NZD.

That's all for now. Working on my control box drawings next.
Chris

[domino11]

It also looks like they forgot to bend the small tabs on the spider plate. Look at the dwgs and you can fix that with a vise and a hammer.

[litemover]

While waiting for the next few pieces to come in, I've decided to build the machine in 3d to gain a better understanding of how everything goes together and make some shop plans. Here is the render from that. Haven't put bearings or screws/bolts on yet, but it's given me some very good perspective of what goes where.

http://s17.postimage.org/78iw6n3nz/CNC4.jpg (http://postimage.org/image/w1sg7amob/full/)
photo sharing (http://postimage.org/)

[litemover]

One more of Z and Y car closer. Still need to find bearings in 3d ,and gas shock.

http://s10.postimage.org/a32j3owwl/CNC_5.jpg (http://postimage.org/image/a32j3owwl/)

[Gerald D]

The ends of the gantry at the top of the picture are suspect.

[litemover]

You mean where the near/far carrier plates meet the tubing? I wrongly mated a motor plate to the inside of the gantry on the right side, but corrected that on the later rendering. I'll put the angle pieces on later tonight.

A friend has some 75mm x75mm x3mm tubing, was thinking of using it for legs and cross braces, would it be ok?

Here's a closeup of the other side of the gantry.

http://s13.postimage.org/dx2nc34lf/CNC_5.jpg (http://postimage.org/image/dx2nc34lf/)

http://s13.postimage.org/8a6aem22r/CNC_6.jpg (http://postimage.org/image/8a6aem22r/)

[Gerald D]

You seem to call the y-car the gantry? The gantry is the big thing that straddles the whole table.

13541

[litemover]

Ahh, yes thanks for pointing that out Gerald. For some reason that side became misaligned. Will clean it up when I do the rails. It's a fantastic design BTW, and the gantry with y car is well conceived with a low centre of gravity. If I can get the bearings worked out in the model, I can sim the machine to play with motion and moments. Can't wait to start putting it all together. Very happy I've gone with this machine.

Thanks,
Chris

[Red_boards]

Can't see the cable chain support, but I assume it's on the RHS of the topmost X-axis?

[KenC]

Don't overlook the cable chain support like I did.... :(

[litemover]

Just two quick stupid questions anyone.

1. I'm about to purchase a welder, and I've seen in the plans that a tig is required, would mig be ok?

2. Can one put 2x z slides in the machine simultaneously, one with router, and one with laser optics using an extra PK296-7.2 for the other slide, and will the weight be ok if I am using the PK296B2a-7.2sg on the gantry and Y car?

Thanks in advance for advise.
Chris

[darren salyer]

I didn't use a tig.
Stick and mig here.

[domino11]

There have been a couple of dual z slide machines built. :)
Should be no problem.

[Gerald D]

. . . . . I've seen in the plans that a tig is required. . . . .

That was definitely not the intention behind the plans!

I think TIG was mentioned only for very fine welding of the gears? The message there was that other types of welding would likely not be successful for THAT application. Stick and MIG are definitely the first choice for a person new to welding. You would scrap the project if you tried to start out with TIG!

[litemover]

Great thanks! That's good news.

[Zouave]

I do not have a MIG welder. Entirely stick welding over here. Worked out fine so far!

[litemover]

Has anyone ever cut their own racks using a fly cutter by chance? Thinking of doing that as racks here are $70NZD per meter:eek:. Which is about $60 USD per meter. I found a video on how to do it here: http://www.youtube.com/watch?v=ma6kdIHwrFI

[smreish]

Chris,
If you have access to a vertical or horizontal mill that could step properly, you could probably save money - but take a bit of time. The racks are not usually hardened, so mild steel would be mostly fine.

I don't personally feel that 70 dollars / meter is that expensive.

Good luck with your choices.

[KenC]

Fly cutting looks like a lot of maths... :eek:
How about using a chop saw, or a band saw or a hand grinder with a cutting disk?
BTW, cutting the rack straight isn't the end of the rack joining, you still need to do some grinding to prepare for the welding join.

[litemover]

Hi Guys,

Just about finished with plans to order steel cuts and am having a small problem. With all dimensions related to gantry and table being accurate, I'm not able to square the gantry V-rollers with the Table X rails. If I square the left side up, on the right side it is about 4-5mm over . Am I doing something wrong, or should I just adjust the table width/gantry tubing length?

Many thanks,
Chris

http://s17.postimage.org/kkoyi6n73/gantry_problem.jpg (http://postimage.org/image/4z7my8b8r/full/)
picture hosting (http://postimage.org/)

[bradm]

If you think about the consquences of being 1mm too small as opposed to 4mm too long, I think you'll agree that this is a conservative approach to the measurements. You can add 2mm of shim to each v-roller, or more or less depending on exactly how the gantry turns out.

However, in that picture above, how accurate is your model of the motor (actually, gearbox) shaft length? Did you shorten it in the drawing? Double check that your pinion gears can meet the rack. Also, I'd expect to see a little more space between the gantry plate and the motor mount plate due to a slippery plastic washer of some kind between them.

[Gerald D]

Chris, have you actually built any hardware or are you just playing on the computer?

[litemover]

I've done laser parts, have drivers, motors, and electronics, bearings arrived a few days ago.. I just haven't ordered the table/gantry steel yet or cut rails, blocks, and prox sensors.

The motor drawings were taken off OM site so I didn't shorten anything. I've just done a mock up drawing to accommodate my size table and make sure I've got a proper list of steel cuts using some spare pieces that my friend has but the x rails and Gantry steel is the same. I'll go over the whole thing again tonight see where I might have forgotten a washer or something in my drawings. Just out of curiosity, how far on each end in the Mechmate CAD drawings does the end of gantry tubing overhang off the table on each side to the X rails outside faces?

Thanks,
Chris

[Gerald D]

If you want to play with this on the computer, try the following:

1. Use the centerline of the table as the reference point. Don't double the dimensions of concern by aligning everything on one side and then looking at the other.

2. Plot the main longitudnals wider apart than what is shown in the drawings. Why?....because the reality of welding is that things move. How much?....well, that depends on your welding experience, but 2mm per side is not too shocking.

3. Plot a 16mm wide rack against the longitudnal (not 0.5inch) because that is a very commonly available size. Then move the rack 1mm away to have some clearance so that the pinion gear doesn't rub on the beam.

4. Your gantry cross-tube: Plot the length as per drawing, but cut the end skew by 1mm, tapering narrower at the bottom....the drawing allows this because all saws don't cut square.

5. Put the x-rail on top of the rack, and put the roller on top of the rail.

6. Put part 1020451/452 inside the gantry-tube end

How thick a spacer do you need behind the roller now?

I had to juggle with all these variables and make a call on the sawn length of the gantry tube. You are welcome to shorten the tubes.

[smreish]

Gerald is the expert on this one, but from practical experience building a few of these, the 4mm you mention is easily taken up by the build averages.

Quickly looking at that measurement you point to as 4mm. My rails had a 1.5mm gap between the 1/2" 20 pitch rack for rail overhang. Then I had usually about 2 shim washers on the vee bearings, which as .060 " thickness. ; then my pinions I shifted about .050 past the shaft for rack engagement. Added together on my machines you are at roughly 3.37 mm. Pretty darn close to your "calculated" distance. Sounds like your just fine.

[litemover]

Thank you Gerald,

I understand what you're saying with the table changing from welding, but I'm needing to bolt mine together on the Y table channel beams, so I can disassemble it if need be, so wouldn't expect too much pull inward I suppose in that regard, would I? Is bolting the crossbeams to the Main Longitudinal not advisable?

[Alan_c]

At some point you will have to weld something, even if its the bolt on legs - and it WILL move! Mine is a bolted assembly and I had to to use straps and a come along to correct for some welding movement.

[smreish]

#5 was bolt, #28 was fully welded. I didn't change one thing with my cut list between both tables.

-The cross members were bolted. 1/2" bolts in 5/8" holes. Thus, collectively 1/4" slop (7mm)
-Rails bolted on....1/2" hole with 5/16" hardware - 3/16" adjustment (5mm)

End result, the cutting, welding, assembly tolerances are in spec with either method.

[KenC]

Gerald did gave great instructions on how to do the welding job correctly in various sticky threads.
As summery of what I learnt from him. (Gotta follow these good practices religiously unless you have more time to waste then I do)
1) Weld as little as you can live with (I keep my weld around 12~15mm longest)
2) stagger weld, don't be lazy , you gotta move around. You gotta spread the heat as evenly as possible,
3) don't weld across the cross-section of the beam.
4) try welding on the thickest part of the SHS & Channel, i.e. along the longitudinal corners.

FYI, my Channel only deform less than 2mm diagonally; Error not measurable with measuring tape on length & width not measurable with measuring tape. I'm very impressed with how it turned out :D .

[rischoof]

A advise,
I have a completely bolted frame, but i didn't use oversize holes in my frame
I made a small simple devise to drill my holes for my cross beams
I cut the tread holes In my c beams, that's M8 if i remember well. then i mount my cross beam with one bold and at the other side i use a clamp. than I have a small devise. that's a m8 bold with a 1.2 mm hole in the center. In this hole a 1.2 mm hardened nail is placed. ( the one you use to nail in a stone wall to hang a painting) I place this bold with the nail in the middle of the all ready made tread hole in the c beam, take a nice hammer, and make a center hole in the cross beam.
Remove c clamp and mounting bold at the other side, and use the center hole to drill the 8 mm second hole.
You have to mark your beams and holes, so you can re-assemble. my marks are engraved in the parts, so I can recognize them after the paint job.
I only use over sized holes for mounting my guiding rail.
For mounting the bolds on the c frame i used standard tapered wigs, the flanges from the c frame are not flat. place a tapered wig in between the bold head and the c flange. otherwise your bold will bend, or break.
12.9 bolds will break when not mounted flat.

[litemover]

Thanks mate, much appreciated for the advice.

[litemover]

Has anyone had any experience with this Belden 4 core cable? I think it might work well, but ran a search and hadn't seen it. Perhaps it is a new type?

http://newzealand.rs-online.com/web/p/cy-cable/6282264/

[KenC]

I use those. On 2 built. ;)
Its considered a reputable brand where I'm from.

[litemover]

Here are some pics of my progress. Finished welding the Y car, squared the verticals on it using m10 allthread, which worked well. Worth the $6.50.

Having a problem with my grinder head, bought a Bosch GWS 150, which has the appropriate screw profile as the laser cut grinder plate, but the head used to position the guard plate is too big to get the rail grinder laser cut piece over. Any recommendations? I didn't use this grinder yet, just bought it, so I suppose I could return it, however, there weren't any other grinders with the correct head profile. It looks like it may screw off somehow, but before I try, wanted to get input.

http://s7.postimage.org/bbjccmhi3/IMG_0240.jpg (http://postimage.org/image/6cvty3dp3/full/)
photo sharing (http://postimage.org/)

http://s8.postimage.org/4zfrokgd1/IMG_1924.jpg (http://postimage.org/image/z4489xlg1/full/)
upload pics (http://postimage.org/)

Getting the Gantry ready and square. So glad I purchased an accurate level, makes a huge difference.
http://s14.postimage.org/6qu6a2oxd/IMG_1925.jpg (http://postimage.org/image/ji8cgkyp9/full/)
photo sharing websites (http://postimage.org/)

[rischoof]

For the grinding skate.
I also had to remove the protection cover from the disc grinder. I did not feel comfortabel with the uncovered disc. I saw to many accidents with disc grinders. I placed a wooden block around the disc. Just make it quickly from some waste material with a jacksaw. The wooden block is fixed with 2 screws to the scate. i do not remember if i had to drill aditional holes in the scate. It did not catch fire from the sparks. You can see some pictures on my build history

[smreish]

This is common challenge.

How much is too big? 1mm or 5mm? I was about 1mm shy of being correct on build #28 so I used a die stone on a drill motor/drill press to open up the profile.
I also was able to purchase 4 new screws that matched the grinder head that were 35mm long and added 7mm spacers to get the grinder to sit in plane and level with the skate.

Both solutions worked.

Personally, cutting up the skate to make your grinder fit is easy and quick. It is a one-time use tool thus doesn't have to be pretty!

[litemover]

This is common challenge.

How much is too big? 1mm or 5mm? I was about 1mm shy of being correct on build #28 so I used a die stone on a drill motor/drill press to open up the profile.
I also was able to purchase 4 new screws that matched the grinder head that were 35mm long and added 7mm spacers to get the grinder to sit in plane and level with the skate.

Both solutions worked.

Personally, cutting up the skate to make your grinder fit is easy and quick. It is a one-time use tool thus doesn't have to be pretty!

Hey Sean,

Thanks, I'll have to cut the skate up as I don't think the collar will twist off the grinder. I think it's about 3-4 mill off.

Regards,
Chris

[litemover]

Should I be using a digital spirit level for the gantry? The level I have is accurate, but I can still shim up things quite a bit before the bubble moves significantly. I'm concerned that it won't be level. Where should I be checking levels on the gantry?

[litemover]

Hi guys,

I've finally accomplished getting the gantry level, and squared while upseide down, but I when I tacked it, then turned it over, I measured how far down the holes were for the rollers with my square from the beams, and one side was off by about 3 mil. When I squared and levled the piece upside down, I used my square to the top of the near and far carrier plates, making sure they were equal and level. But when I turn it over, I am pulling the dimension off the holes for the rollers, and they are not even. Should I be squaring this based on the rollers from the beams dimension, as well as the beams level, or did I do it right when upside down? How would I correct the rollers if they are off? Any tips would be helpful.

Thanks,
Chris
http://s14.postimage.org/3x8w85k4h/IMG_0244.jpg (http://postimage.org/)
upload foto (http://postimage.org/)

http://s14.postimage.org/63372nnkx/IMG_0245.jpg (http://postimage.org/)
images (http://postimage.org/)

[Surfcnc]

Chris

The gantry can be pulled into position with a system of clamps.
Find your high side and then secure the other three ends on some blocks.
On the high side then progressively wind down a clamp to flex the gantry into the correct position.
You will need to wind the clamp past the "exact position' as it it springs back up when released.
This method makes it very easy to correct any distortion from welding.

Regards
Ross

[litemover]

Thanks Ross, I read that process, was just trying to get it within 1mm before I tried it. I think I managed to get it real close now. It should be simple to true now with the blocks. Onto the table now.! One question, should I true it prior to putting in the final welds or after the final welds?

Thanks,
Chris

[Surfcnc]

Hi Chris

After, as it might move on you again when doing the final welding.
The blocks method can easily correct a fully welded gantry.

Cheers
Ross

[litemover]

Hi guys,

I was able to get 75mm x 50mm unequal angle iron for the Y rails thinking that was all that was available here in NZ... This was before I found the 65 x 50mm rails from another supplier, which I purchased for the X rails. My question is, since I have already drilled the 75mmx50mm can I use it and cut down only the 50mm side to the 28mm, or do I have to cut both sides down so that the 75mm equals 65mm?

Looking at clearance for the Y car, it seems there might be just enough room for an additional 5-10mm each side, but you guys would know better than I how much clearance there is.

Thanks,
Chris

[smreish]

The long leg of that angle should be "in board" of the carriage - so you should be fine on clearance issues. The upright, milled edge is outboard and not cause any interference. You should be fine with the x axis. The y axis car might need a little grinder clearance on the monocoup y-car - but that won't affect much.

Worst case, you keep the odd angle for the x and just remake the y.

[litemover]

What about weight issues? Any? Thanks Sean.

[smreish]

If your asking if the additional weight will affect the y-carriage - then the answer is not really.
You should be not really notice the additional weight if using any type of geared transmission/reduction drive. Direct Drive - Maybe, but not likely.

I added a 48" Z slide , dust collection and another Z in my carriage, with upgraded to 3/16" wall steel tube - and still didn't notice a difference. I was using 7.2 : 1 steppers and 30T pinions.

[litemover]

Cool, thanks. Was thinking that the rails would be too heavy for the gantry since I am already using 3mm tubing in the gantry, but sounds like it will be ok. It's a relief I don't need to cut them down.

[smreish]

Worst case, you may have to set your acceleration and deceleration profiles on the motor tuning in Mach 3 a bit slower (longer time) to accommodate the induced drag on the system due to the higher mass....but unlikely.

Best,
Sean

[litemover]

Have a bit of a problem, my long X beams are bowing slightly, about 3 mill in the center twist. When i clamp them together, they will straighten out, but what I was wondering was, if I bolt the rails to them, will they stay straight? Should I drill the rail holes through them while they are clamped together to straighten them or after the table is upright?

I'm bolting the cross members to the table with M10 bolts and a spring washer. So far it went together well. Drilled M11.5 in the crossmember, M10 in the beam.

Thanks,
Chris

[litemover]

Nevermind, I saw the post about welding the beam. Disregard.

[litemover]

Just curious, is there any way I could use 2x 4 core cables instead of 7 core for the e-stops, as it's very difficult to get 7 core here for anything reasonable. Will it affect any performance?

Many thanks,
Chris

[Zouave]

I can't think of any reason why it'd make a difference, other than an extra cable entry/exit on each box. It really should work exactly the same as long as your individual cores are the same size as the 7-core would be.
How much 7-core do you need, in total?

[KenC]

I use cheap 2 core wires for light bulbs, & didn't even see the need to bundle them together. As long as its for AC & the correct voltage rating, if it can light a florescent lamp its good enough for the relay coil & switches which almost no current running in it.
Or if you must, you can get some Cat 5 cable with 8 twisted pairs in it. Just check if the Voltage rating fits the bill.

[litemover]

Well, my table is 3900 x 1550. So whatever much that is, not near my notes yet. Cat 5 would work? That would be awesome! Thanks!

On another note, I think my grinder broke while cutting rails. The teeth sound like they are grinding against each other on the inside. I took it apart and looks ok, not sure what the noise is.

[Red_boards]

I used 4 core shielded because the price was right. Ended up with about 1" diameter bundle of wires running from the machine to the control box. My router power is roof fed to keep it remote from control wiring.

Grinder bearings are trashed is my guess.

[KenC]

Actually, if your motor cables are shielded, you can bundle your router power cable with them. that is the whole point of having shielded stepper motor cables. E-stop circuit is 240Vac, even without shield, it takes a lot more than just VFD to corrupt 240V ac. Even a plasma torch cable did no harm to it.

[litemover]

Thanks for the input guys. I'll probably use either 4 core or cat5. Just having a hard time getting cheap 7 core in the lengths I need. Can only buy 50 mtrs.

The grinder was trashed, and started getting way too hot to work with, so I returned it and they exchanged it. They weren't going to, but eventually did. phew. I'll be much lighter with it this time. It's a bosch professional, and yes, I think the bearings must have gone last time. Trying to be lightiner, and grinding each side through. Doing it all the way through makes for a slanted rail.

Cheers,
Chris

[KenC]

Think rubbing/slicing off the rail instead of chopping when you use the grinder.

[litemover]

Thanks Ken,

Is it better to cut from one side or from both, resetting the height to ride on the flange?

Cheers,
Chris

[KenC]

I personally prefer cutting from 1 side & weld-shut the height once it is decided.
PS, the height will not be dead on... BUT do your best to keep them within 1~2mm variation (remember, think slicing/rubbing). The shims will do the rest in the later part of the build.

[litemover]

Ok, just finished cutting down my rails, they are hardly precision cuts, kind of jagged. I'm hoping the grinding will make them a bit more precise. The second X rail, I cut 1mm higher so I can have some leeway to grind it down a bit more precise.

[smreish]

Chris,
Did you put a grinder disk in after cutting down and make a few passes to even out the top profile.....like a surface grind making it really flat before you start profiling?

[litemover]

Hey Sean, thanks for the tip. Going to do that today. Unfortunately, one rail was cut from 28mm to 25mm slanting one side to the other due to the cutting disc not being perfectly level. May need to do that one over...

[litemover]

Just a quick question, if I want to weld 2 offcut angle irons together to make up a new Y rail, would that be advisable? I need to cut down a new rails one of my rails were cut to 25.51 mill.

Many thanks,
Chris

[Alan_c]

What process/system are you using to cut your rails down?, using the sled I made enabled me to achive a total variation along the full x length of 0.2mm!
see here:http://www.mechmate.com/forums/showthread.php?p=5013&postcount=45 and lower down in post 57.

[litemover]

That's sweet. Wish I had seen that one prior to doing mine. I used the skate. It's ok, and the last one turned out pretty good, but the other ones aren't that great. I'm going to need to grind them down with something to get them flat. Perhaps I ought to use something like this but with a grinder head, instead of the skate.

[Surfcnc]

Hi Chris

Steady as she goes on the rails - 3mm variation is not good enough so ditch it and consider that as practice.

Treat the rail cut as two parts ..
1. remove the bulk
2. fine tune the height

As Alan has suggested the plate mounted grinder works great.
Set up on a straight surface, I used my X beams and then grind down the top of the rail square and to an exact height using successive passes.

When I say grind I mean sand.
Use a fresh grinding disk with a sanding disk as the cutting surface.
Start at about 40 grit or rougher then go up to 120 for a mirror finish to the rails.

My thread details the methods used. Sanding the rails will vastly improve the surface finish and significantly shorten the time you spend making the rails.

Regards
Ross

[litemover]

thanks, by ditch do you mean completely start over and buy new angle iron? Just curious, what is the lowest I cut the angle iron down to? Can I re-cut or sand them to 25mm or 24mm? if so, then I would be able to get them nice and even. I've been cutting on my X rails, but I don't think they are too flat either. I definitely underestimated the level of precision needed for these. The two long rails are 28mm for most of the rail, then they dip down to 25.5 and 27mm toward one end.

Been working low coz my xrails are quite heavy, hard on my back.

http://s7.postimage.org/ez3vibl9n/photo.jpg (http://postimage.org/image/kna697plz/full/)
photo sharing (http://postimage.org/)

[Surfcnc]

Hi Chris

It is up to you to determine if 25mm is enough.
When the plans say specify something that's what I do.
"Ditch It' means recut one at the correct height.

If you have 3mm variation in height I suggest you have a real problem with your method.

1. Don't work low - get some tressles or saw horses and a few blocks of thick timber and lift one beam up on them at a good working height.
2. Look at this post http://www.mechmate.com/forums/showthread.php?p=42075&postcount=186 and copy my setup.
3. Note you clamp the rail to the board and the beam and cut the rail from the back. It is impossible to get 3mm variation using this method.
even if the beam was bent over its length the rail is bent to match that and the cut remains at a consistent height.

Ross

[litemover]

Hi, thanks for the info here. BTW, the inconsistency didn't come from the cutting, they cut initially within .4mm, but since one rail was off to the other, I thought sanding it down would work. Perhaps the disc expands when hot or something changes. Well, I suppose I learned the lesson the hard way. I'm just curious if I can somehow salvage this, as it would cost me $200 more in angle iron to recut them, not to mention the couple more days.

My X length rail total is 4500mm,
1 X rail is sitting good at 27.5mm to 28.45mm
other X rail is sitting at 26mm first quarter to 28mm
My Y length rail is 1950mm,
Both Y rails are at 26mm +/- .5mm

Does anyone know if it would present any problems to have the rails at 24mm high rather than 28mm, and use 4mm flatbar to shim them up with?

Thanks for the info on the methods everyone. I'll definitely use a better method.

Cheers,
Chris

[Surfcnc]

Ok salvage it is.

There is no harm in making the rails and checking the fits yourself with out any packers. If necessary put in some packers should problems arise..

Some tolerances will change regardless.
1. the gantry / Y axis car will move towards the top of the rail
2. the swing plate mounted to the gantry / Y axis car will move away from the rail

Ross

[Gerald D]

The drawings used to show 25mm rails and they did work sort of okay.....

- The skate rollers need to miss the curved fillet inside the corner of the angle iron.
- When using small pinion gears the motor shafts can foul on the gantry ends
- the slots in the motor plates don't allow the motors to swing that far up

[litemover]

Thanks for chiming in Gerald. What if I place a 10 x 3mm flatbar shim under the rack? Will that space the swing plate far enough back into position ok? Suppose I could order more angle iron later on if this doesn't work... Not much to lose trying at this point.

BTW< what is everyone using to check the rail height across the entire rail? Gauges? I've been using my calipers and square.

[Gerald D]

A spacer under the rack is more trouble than solving the other implications will be. Simplest is a pinion size just bigger than minimum (if you plan on belts/gears anyway.). Otherwise a bit of local filing/grinding will get the motor plates swinging further up.

[litemover]

Thanks Gerald.

I have one X rail that teeters between 28.00 and 29.34. Am reticent to sand it further down in case I mess it up. Perhaps will just lightly sand the areas that are too high.

Out of the bad X rail, I can cut a segment out that would be 28mm long for one of the Y rails 2000mm long.

Which leaves me to only have to purchase one more 6m long piece of rail for $60 NZD. What I'm wondering is, would it be ok to weld together 2 pieces of angle iron to create a single Y rail 2000mm long for the other X rail, one piece would be 1500mm, and the other 500mm? Then cut and bevel that one down to 28mm as one piece? If this is the case, then this mistake would only have cost me $60.

Also, one other question, can I use M10 stainless bolts on the rail skate for height adjustment, instead of M12, as this will save me $40 in tap, 13/32 drill bit, and setscrew/nuts. The hole on the rail skate taps fine at M10, so was just wondering as this would reduce my mistake down to $20 (minus a few days work) while keeping a 28mm rail height.

Many thanks for all the help guys, She's coming along. Should have the table, gantry, and Y car finished early next week but not painted. Will redo the rails on the built table instead of on the ground.

Cheers,
Chris

[Surfcnc]

Sand down the high parts :eek:

No way ... deck the whole rail to a single height with a series of continuous actions along the whole length of the rail.
The high parts will get touched while the low parts will be left alone.
The final pass will lightly touch all of the rail ensuring a consistent height.

i'll leave the rest to someone else.

Regards
Ross

[litemover]

That is what I was trying to do with the other rails which brought them down to 25-26mm. Something must be wrong with my grinder when it gets hot. It's a bosch too.

[Surfcnc]

Could you show us a few pics of how you did it and or the jig you used.

Ross

[litemover]

Sure, just used the skate in the plans. Leveled out the bolts with a square and digital calipers. I used a sanding disc on top of a grinding disc. Will post photos when I get back to the shop next week.

[Surfcnc]

Chris

This is no mystery, carefully study the attached photo with me.

13725

By just using four bolts, no matter how carefully measured for height, error creeps into the process.
The reason for this is that the bolts are very close to the disk itself.
They are clearly visible in this shot.

This jig provides an very large flat surface that controls any movement both left to right and back to front.

Also note that I have two melamine surfaces sliding over the top of each other.
This is to minimise the friction on the surfaces so that thay slide with a smooth action.

Looking at the pics of the rails you posted you have not been able to control some of the the front to back movement with just the four bolts sticking out of the top plate of the skate.
Hardly a surprise as the aspect ratio of the height of the bolts to the width is working against you.

By comparison the jig I have used supports the grinder over at least 3 times the distance front to back, let alone any calculation of the total surface area the jig bears upon.

PRACTICE

The next step is to make a jig, then practice on something non critical.
I know that sounds a obvious but so many rip into expensive materials with no previous experience then wonder why something has gone wrong.
That is exactly why those smug tradesmen with their lifetimes of experience laugh at a newbies trying to emulate their skill.

Good luck with your rails, you now know everything you need to know !!

Regards
Ross

[litemover]

Thanks Ross, I'll definitely make that jig and use it on the rails once I get the table up. I'm going to shift on getting the table up next week so I can have a higher surface to work on. Then I'll get the melamine boards to make the jig.

Thanks again for the tips.
Christian

[smreish]

http://www.mechmate.com/forums/showthread.php?p=7510&postcount=29

Previous production version of same idea....
Notice plastic PVC laminate on bottom of plywood sled for gliding

[Alan_c]

You dont seem to mention a cutting disk, are you using a cutting disk to cut the angle to the correct height or are you grinding it down with the sanding disk/grinder combo?

[litemover]

Found a great article on how to heat straighten beams without welding them, just with a torch. http://www.fhwa.dot.gov/bridge/steel/02.cfm#d. Going to try it tomorrow in my beams.

[KenC]

Actually, both are the same thing. I find welding is the easier way to apply heat...

[Surfcnc]

Chris great detail there.

Ross

[litemover]

It's a good paper on bending beams with heat, knowing any beam can be straightened with this method is a relief. Plus, I don't have to weld, or grind them out later. Should be interesting. I will try using the V method on my beams and my rails which have slightly bent.

Will continue with cutting rails later in the week.

[litemover]

Just a question about the support board. At the moment, I can get 2x 12mm 3660 x 1800 mdf. Can I glue those together for the support board material?

Thx

Chris

[Red_boards]

I'd say it's not a problem. I would use epoxy for glue.

You get to do this again when you glue the sacrificial layer on after bolting the base board to the frame.

PS there are some good suggestions in the forums about drilling through both sides of the base board cross supports so you can easily drill the base board, and for clamping the base board under the supports when drilling so that you get to work from above, rather than getting sawdust in your eyes, like I did.

[litemover]

Hey Red, thanks for the advice. I did drill straight through my cross channels for a vacuum plenum later on, so now I know to clamp the board to it and drill through in order to get it drilled. Thanks!

Chris

[litemover]

Help,
Having no luck with bending one of my large beams into place. I heated one of them straight, then the other one over compensated and I haven't been able to get it back.. Can anyone tell me how to weld a beam straight that is bent on the webbing side, not the flange side? Ie opposite to how it is bent in the illustration that Gerald made please?

Thanks
Chris

[KenC]

Applying correct amount of heat with torch is way above me. Hence, welding is my prefered heat source which I can gauge the heat to a very close ball park.
I can't offer much help on the correct way to do your straightening job, also, I really don't understand what you want. a sketch would be really helpful.
For now, all I can tell you is that metal will string towards the side where you apply the heat. i.e. the heated spot will become the inside of a bow. (if the beam started out as a perfectly straight piece; I get confuse with bow-in & bow-out... :o)

[litemover]

Here is a pic of the bend with explanation. I've tried that but it just became worse. Not sure why.

http://i45.tinypic.com/etrwu8.jpg

[xraydude]

Can't quite make out the text on your image. I believe that you are indicating how it is bowed, not how you want to bend it. The method that Gerald described in the thread you mentioned is probably the best. I did not have to do this on my main beams, and have not had to do this with any channel as heavy or large, but it should work. I would start in the center of the bow, make the welds, let them cool and check for any change. If it has improved at all, I would work out towards the ends about every 24 inches as Gerald recommends. How bad is the bow? You may be able to compensate and straighten when welding on the supports.

http://www.darkforrest.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=5465&g2_serialNumber=1

Ted

[litemover]

Great, thanks for the advice. I'll give it a go. Shall I weld just on the bottom flange or both bottom and top, and do I just weld on the inside?

It's bowed about 8mm, but it was only 4mm till I started heating it.
Thanks,
Chris

[xraydude]

When I have done this on lighter gauge and smaller channel (for trailers), I did both flanges, only on the inside, to try and keep out any twist. You will need a lot of heat. Here is a link that may help explain heat straightening in general. In particular, check out Fig.5.

http://www.metalwebnews.com/howto/contraction/contraction.html

Ted

[litemover]

Well, I have nearly finished tack welding the table up. As shown. I gave up on trying to straighten the beam with heat as it simply will not straighten this way. I figured I'd try to install the cross braces then straighten it with an all thread clamp while heating it up, then tighten all the cross members and tack weld them. Anyone else use this technique? As you can see, the dimension is suppose to be 1980 all the way accross, and it is either short in the middle, or long at the ends.

Still a bit of structure to weld on this massive table. Not sure how I will turn it over without 10 guys:) I used bolts on the cross brace frames so i could take it apart if need be, then turn it over.

http://s21.postimage.org/4375gqxx3/IMG_2003_1.jpg (http://postimage.org/image/67rihtzjn/full/)
pic upload (http://postimage.org/)

[litemover]

More progress on frame. Need to drill holes on webbing for the all thread clamp to get it to straighten out prior to welding the legs on. I'm also thinking of loosening the cross frames up where the gaps between the main X beams are too long, then welding the legs on where they are supposed to be on the beams, then tightening the cross frames to the legs hopefully pulling the beams straight. Welds are for the most part clean, except for a few that were difficult to get to. The argoshield makes a night and day difference to flux core any day.

http://i47.tinypic.com/2lvmmxk.jpg

[Andrew_standen]

Looking good.
That's some heavy looking metal there.
Nice stuff.
Cheers
Andrew

[litemover]

Thanks, it is pretty heavy, that is for sure!

[litemover]

Here is how I managed to correct the beam that was crooked. I use the allthread to pull them together, then I lifted them and hammered in the bottom.

http://i46.tinypic.com/2lboswj.jpg

And on the inside to spread them apart:

http://i49.tinypic.com/x4etr5.jpg

I'm hoping that this didn't cause any more problems, i.e. twisting, or anything like that. It seems as if my flanges are becoming a bit bent with all the weight on them now.

http://i46.tinypic.com/23ijw2s.jpg

[smreish]

...love a good trolley jack!

[litemover]

What would I do with the trolly jack Sean? Is that how I should turn it over?

I have 3 mdf boards, each 12mm thick, can I get away well enough with 2x for the support board, and 1 for the spoiler lard, or should I glue all 3 together for the support?

[sailfl]

1 support and 1 spoil board will do it.

[litemover]

It will be quite flexible if I use only 1-12mm board as support, won't it?

[Alan_c]

We usually use a 30mm board as the support and 22mm as sacrificial surface. If you want to use whats on hand, glue two 12mm board together, mount them to the table with the counterbored holes as per usual, fix to the table and glue the last 12mm board on top, you wont get the same working life from you sacrificial board but at least you can start working.

[litemover]

great, I liquid nailed the support boards together. Should be ok. Turned the table over today, all going well. Going to start priming it tomorrow.

[litemover]

Here are some primed bits, going to rust converter the main table prior to priming with a 2k primer..




http://i49.tinypic.com/1z3yyj4.jpg

[litemover]

Ok, back on the rails now that I have a flat surface to work on. Built the jig for the rail grinding, per Ross' rig. Used 300mm x300mm Melamine about 16mm thick x2. Did a test and it worked out so much better. On the test rail, I was only off by .2mm across apprx 1.2m stick from 28.25mm to 28.45ish mm. Hoping that is going to be acceptable on the big pieces.

A note: I upgraded to 125mm Pferd Discs as they were only .30c more ea for 10mm extra material. Seems to be worthwhile and they smell just as good as the smaller ones (love the smell of pferd discs burning in the morning:D ). They fit my Bosch 115mm grinder post so I figured what the hey. I also purchased some F clamps, which seem to do a heck of a better job than the old plastic clamps I had around.

Also, made heaps of progress on the rest of the table, and now switching into electronics mode, and working on the Zslide. I'm going to get everything rolling on rails before I paint over the primer incase I need to rip into something to straighten it out as the x beams still are on perfectly level or straight, though they are much closer now. What a headache it was fixing messed up 180pfc beams. No matter what the guy says, next time I won't take delivery on the beams if they are mucked up as it will cost triple in gas and time just to straighten them out.

Here are some pics.

http://s16.postimg.org/ok37l5aol/IMG_2065.jpg (http://postimage.org/)

http://s16.postimg.org/6ik2ncgnp/IMG_2067.jpg (http://postimage.org/)

http://s16.postimg.org/6wlemy0r9/IMG_2069.jpg (http://postimage.org/)

http://s16.postimg.org/92fphg47p/IMG_2071.jpg (http://postimage.org/)

http://s16.postimg.org/ymhznvplh/IMG_2073.jpg (http://postimage.org/)

http://s16.postimg.org/jf203ixqt/IMG_2077.jpg (http://postimage.org/)

http://s16.postimg.org/wx8wft9w5/IMG_2079.jpg (http://postimage.org/)

http://s21.postimg.org/eei9m3mmv/IMG_2061.jpg (http://postimage.org/)

[smreish]

...I think you figured it out, but the slower (lighter) the passes you get better results.
As you push to hard, the blade deflects up and gives you those minor errors.
As a finish - put that sanding disk on the grinder with 36/80 grit on that grinder and surface grind that rail section dead flat. Then you have a really flat top referenced surface to grind your profile on.

I have now made 3 sets of rails from scratch!

Sean

[litemover]

Cool, thanks Sean. I was doing the lighter passes, but when I got to about 2 mm left on the rail, I went for one heavy pass as the wheel gets stuck when it gets too deep. Is that what I'm supposed to do? I'm going to sand them out today flat on top.

[Surfcnc]

Chris

The jamming is from the cut closing up a little, probably from the heat.
So stop and relieve the cut by bending the remaining top back slightly to open it back up again.
Use some vise grips and run along the top of the cut bending it back every 200mm or so.

Ross

[smreish]

...Ditto what Ross said.

[litemover]

Thanks guys, yes I figured out the vice grip trick. It seems that the best time to cut through all the way is when the other side of the rail is smoking a bit. After you see smoke, then the next pass should cut right through fairly easily. It takes a lot less disc too if you just keep cutting until it slices off. I did one 2.5m rail yesterday with half a disc so that worked out well. It seems the sanding though gave the top a bit of a slight convex shape. Not sure why that happened, perhaps the backing disc was not as hard as I had hoped for. Will try with a different backing disc today.

Thanks for all the help, it's really working well now. .1mm variance last night across 2.5m so looking quite nice.
Chris

[smreish]

Use a regular grinding disk (new) as the backer. This is a very rigid precise backing plate.
Or, one of your thin cut of disks. Light pressure until you see even sparks.

[litemover]

Well I finished all my cutting and sanding, they turned out good but I have a slight problem. One X rail is 28.9 mm and the other is 28.1mm give or take .2mm tolerance. Should I grind down the 28.9 mm one to match? I recall doing something like this before but ended up messing up the evenness of the rail by trying to take off too much material. I learned that one should do all the cutting with the jig at same settings, then all the sanding, then all the profiling. Don't cut, then sand the same rail, and move on to a new one to cut or you'll end up with uneven rails from one to the other.

Anyhoo, a whole manual could be written about grinding rails! Tomorrow I will profile them.

I ended up welding two pieces of smaller rail together for one of the Y rails so I wouldn't have to order yet another one. Here is how I did it. (Excuse the welds)):D

1. First I put the two manufactured ends together, which made them relatively fit easily together, straight.
2. Clamped the two halts flush to the edge of the main X beam with a melamine board underneath.
3. Then clamped a piece of 50mm x 6mm flatbar on the backside of the rail.
4. Took a piece of yellow nylon line and stretched from end to end to make sure everything was straight (it was)
5. Tack Welded, then welded them together, rechecked the line.
6. Grinded out the welds and flap disced them flat.

Thanks for the help Ross and Sean, and everyone. They are very precise now over the length of rail.

Cheers
Chris
http://s14.postimg.org/pm4atk0f5/IMG_2084.jpg (http://postimage.org/)
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windows 7 screen shot (http://postimage.org/app.php)

[Gerald D]

1mm difference in rail height from one side to the other is no problem. At the end of the day you trim/face the table surface so that everything comes to "zero".

[litemover]

Thanks Gerald, That's good news that I don't have to grind the tall rail down further. Do I shim up the opposite rail to match in the end when shimming them?

[Gerald D]

Why bother to raise the rail if you don't even know your main beams are the same height, taper or whatever? Believe me, when you start shimming, you will be grateful for having one less factor to measure.

[litemover]

Probably will work out for the best during shimming, because, ill bet one beam is out by 1mm anyway.

[litemover]

Yesterday, I finished cutting and sanding all the rails then profiled 2 rails, (a test rail and one of my X rails) before it got too dark outside to work quietly. The skate worked really well, was impressed at the quality of the final profile and how easy it was to fine tune. Really slid well with some cutting oil across the rail. It was a bit difficult getting started as the skate was sticking due to the bend not being sharp enough so I adjusted the eccentrics and lubed it up. I suppose I needed to specify K factor or bending radius for that piece to get it perfect. One set of bearings kind of sticks out a bit to the side but it works well still. I would caution being very careful your hand doesn't hit the grinder as it is entirely possible to happen (it took a chunk out of my finger)

The thing that made a difference for me was using a grinding disc, cutoff disc (pferd 1mm), and a sanding disc sandwiched together. The 1mm cutoff discs between the grinding disc and sanding pad smoothed out the dip in the grinding disc and made the whole sanding surface flat and hard. It also helped when the apparatus became too low and the heads of the bearing post screws hit the wells of the rail flange to add yet another cutoff disc to the sandwich. This spaces the sanding disc 1mm further down for a nice final sanding. I used 36grit to start, then switched to 60 grit when the profile top was 2mm, then went over a pass with 100 grit once I had to added the cutoff disc to the sandwich. Then went over the whole thing lightly by hand (block) just to polish with a 400 grit. I'll post some photos of the finished product later on but here are some of the test.

http://s21.postimg.org/woaq237uv/IMG_2111.jpg (http://postimg.org/image/7v161foub/full/)

http://s21.postimg.org/p9le9plzb/IMG_2113.jpg (http://postimg.org/image/8ylade9hf/full/)

http://s4.postimg.org/70hrdjust/IMG_2102.jpg (http://postimage.org/)

http://s4.postimg.org/j137ea27h/IMG_2109.jpg (http://postimage.org/)

[bradm]

I wore welding gloves while working with the skate, and I did take some leather off one of the gloves; it's easy to have a hand slip. Your test rail looks great!

[smreish]

...that looks incredibly familiar! Well done.

[litemover]

Thanks! I've finished cutting and profiling the rails. They turned out excellent, thanks to a lot of help from people here. Just need to redrill a few holes in some of the new rail, then I will be mounting them and testing the roll soon.

Next week will be ordering control box stuff, will take a while to get, but should be quick to put together.

I don't have any rack and pinion yet, will need to order overseas for that. Not sure where would be best, probably china.

ok, will post progress tomorrow or sat.

Over and out!
Chris
http://s15.postimg.org/rs8nun957/IMG_2115.jpg (http://postimage.org/)

[parrulho]

well done!

have ordered my rack and pinions from www.mooregear.com
It was the only company i found able to shipping it to me.

[litemover]

On Friday I leveled the table, and used the 2m all thread clamps I made to tune the X beams a bit more which really worked well. I had cut into one leg and shimmed the X beam on that leg with washers, then welded it back shut. The beam was level then on the Y axis. I essentially squeezed them into place then ratcheted down my 75 PFC crossbeams till very tight. When I loosened up the clamps the machine was completely level in the X direction and by looking at the level on the gantry, it looks as if they are level in the Y direction as well but I will fine tune that with my laser as soon as I figure out how to do that.

I then mounted the X rails and measured 15mm from the edge of the X beam to the edge of the rail before clamping them down. Then went through with my square to make sure the 15mm gap for the rack was consistent all around, which it was; however, There is a slight bow in the beams so it's not completely square from flange to webbing, but there is enough space for the rack nonetheless. I'm thinking it must have happened when I tried heating them to straighten them. An engineer friend I have said to never touch heat to the webbing part of C channel as it will warp. Well it must have warped, or must not have been square to begin with. Wouldn't doubt it either way. :rolleyes:

After I clamped the freshly ground rails, I couldn't resist, had to mount the gantry and test-roll it. I couldn't believe it, it rolled SO smoothly and on all 4 wheels not a single adjustment had to be made. The spacing from Xrail to Xrail was spot on the money, which was a huge relief to say the least. :)

Next were the Y rails, which I'm not sure what has happened but they were too far apart. The gap is further than 15mm on each rail to the Ybeam so the car wouldn't roll right. I had to take off the M12 thin nut on one side and use washers instead which must be ground around the edge or something because the washers are causing the bearings to lockup. So will see if I can get smaller washers, or just drill through some M10 washers to M12 size. With a bit of loosening of the nuts on the Y car, it started to glide nicely, and on all fours. So my machine's tolerances look to be in the green, what a relief. No major adjustments!

Having my stop blocks cut, and needing to get the turned parts turned soon. I'm going to order the three C's tomorrow, Cable, Contactor, and Control box, along with door interlock, and so forth. Was thinking of using this contractor any thoughts? Contactor LINK (http://newzealand.rs-online.com/web/p/contactors/6090144/?searchTerm=609-0144&relevancy-data=636F3D3126696E3D4931384E525353746F636B4E756D6 265724D504E266C753D656E266D6D3D6D61746368616C6C267 06D3D5E5C647B337D5B5C732D2F255C2E2C5D5C647B332C347 D2426706F3D313426736E3D592673743D52535F53544F434B5 F4E554D424552267573743D3630392D303134342677633D4E4 F4E4526) I was looking at 24v contractors, but seems just as expensive to do that with a 24v PS.

Here are some photos of my progress. I have a black and decker self leveling laser, along with a Bosch laser distance measure so I'm hoping that between those two items, it'l make the shimming a lot easier. Someone mentioned using Coke cans for shimming material, so I'll probably be getting some coke soon, or redbull if that will work :D

Have a good weekend!
http://s16.postimg.org/9tue672np/MG_7081.jpg (http://postimage.org/)

http://s16.postimg.org/v4ryagks5/MG_7079.jpg (http://postimage.org/)

http://s16.postimg.org/5ai5koks5/MG_7073.jpg (http://postimage.org/)

http://s7.postimg.org/78m0t7e3f/IMG_2122.jpg (http://postimage.org/)

http://s8.postimg.org/72i7a7gpx/IMG_2126.jpg (http://postimage.org/)

http://s05.flagcounter.com/count/5qiQ/bg_FFFFFF/txt_000000/border_CCCCCC/columns_5/maxflags_50/viewers_0/labels_1/pageviews_1/flags_1/ (http://info.flagcounter.com/5qiQ)

[KenC]

Are you gonna shim the rails?

[litemover]

Hey Ken, I sure am, but need to make a laser car first out of some angle iron.

[Gerald D]

I think the y-car is the wrong way around? (cable carrier connection should be on the other side of the table?)

[litemover]

I need to flip the gantry around, forgot to do that the other day but thanks for reminding me.

[litemover]

Hi guys,

Well this may be a silly question, but can't find it anywhere and could use some advice. Is it ok to use a 4 pole contactor on a single phase machine? In other words can I use just 2 poles of it? I will update it to 3 phase once I get into a building with 3 phase and spindle so will want upgradeability.

Also, if I am using the OM PK296b2b7.2 motors, Gecko drive G203v, can I get away with 12amps on the contractor rating?

Many thanks,
Chris

[KenC]

Surely， you can use just 2 poles of a 4 pole contactor.

Even if all 4 motors are drawing 6 amps at 60V, it will only draw 12A from the wall 110V single phase wall plug. 6A from a 230V single phase wall plug.
BUT you gotta factor in other thing that you may draw power from the same plug, such as the fans, disco light, etc etc...

[HomeMadeCnc]

Nice looking machine,
Cheers,
Tim

[litemover]

Thanks,

Hey Ken, I was wondering, if I do go with a 4 pole, does that mean that the 4 pole can only handle pulling 3amp per pole? or up to 12 amp per pole?

[KenC]

Hi Chris,
I don't understand your question. but I would suggest you study the specs of the contactor; Almost all contactors which I used has their rating printed or cast on the housing. Look for current rating of EACH contact. If 1 contact can not handle the current, use 2 in parallel it 2 is not sufficient, use 3 ... etc etc ;) . not the smartest & the safest thing to do but if u really can't part with the extra US$20.... ;)

[Gerald D]

A multipole device has its rating per pole. Therefore 12A per pole.

[litemover]

That's good news. Thanks guys.

[litemover]

I've read a lot of the posts about Chinese spindles and am impressed. Looking at the current landscape of Chai spindles, thinking about ordering a Chinese spindle, but not sure which type to go with, the 4kw air cooled or water cooled. There are so many Chinese sellers too, are they all good? Anyone in particular who stands out as an exceptional Chinese spindle dealer? I've seen plenty of spindles all looking the same, but priced widely different to each other. Some with 4 bearings, some with Japanese bearings, or German bearings subbed out.

Also, I am thinking of purchasing either a Hitachi 5hp VFD or X200 3hp. I read somewhere on here that a 3 phase VFD can be run single phase, is that true? Is there a huge difference between 3hp spindle and 5hp in terms of ability to run 24/7?

Thanks for any info.

Chris

[HomeMadeCnc]

Hi Chris, I run a Chinese 3hp spindle on a 1 to 3 phase VFD. Works great. Super quiet compared to the 3hp router. I have run the spindle on one phase but that wasn't a good sound. I run my setup on average 6 hours a day. A few times run for 36 hours with no problems. Then there's the amount of bearings, 2 for wood more for metal. Pick something that's easy and works, the cash will follow for the 5 hp upgrade.

Cheers
Tim

[KenC]

Bigger is always better. Other factors to look into are 1) cost (obvious) 2)can your house electrical system take the load. Don't want to see you burning down the house just because your house wire spit fire due to excessive overloading.

[litemover]

Thanks for the help guys. I really would like to get a 5hp water cooled 4 bearing spindle if possible but don't want to burn the house down or anything like that :D. Not sure how the house will handle it but planning to move into a commercial space. I'm on a 230v 50hz grid at the house. Will check the breakers out.

My main questions are, are most of the Chinese ebay guys fairly reliable and with regards to the VFD, should I go with a particular one? I've tried searching for a few of the ones mentioned on the site but they are no longer there. Someone said that it's better to go with the Hitachi inverters over the Chinese ones. I was reading here that the 3 phase inverters can run on 1 phase, is that true with the Hitatchi 3 phase 5hp VFD too?

Thanks,
Chris

[bradm]

Hmm. Let me be a little contrarian here.

What advantage do you expect to get from a 5hp spindle vs a 3hp spindle? Are you planning to work with exceptionally large cutters?

Don't get me wrong - there are times when bigger is better, and overbuilt can be an advantage. However, depending on what you are trying to achieve, you may spend more than you need to make a machine that requires an atypically large and expensive power source, and doesn't perform any better on the primary task.

A MechMate with a 1 HP router is clearly not operating to it's full potential. Moving to a larger router, or up to a small spindle gives an obvious improvement. Moving to a 15 HP spindle would pretty clearly outstrip the capabilities of other sections of the MechMate. Whether the point of diminishing returns sets in at 4HP, 5HP, 7.5HP, 10HP is probably worth a few moments of consideration.

I am a big fan of the Hitachi inverters. Be aware that when operating on single phase input, you may have to upsize the inverter (use a 7.5 HP inverter for a 5 HP motor). Your supplier can help you sort this out. Usually the smaller inverters (3 HP and below) have single phase versions without upsizing.

[KenC]

3Kw or 4hp is about the safe operating capacity of a single phase 230V 50hz supply on a 13A fuse. That is what I am running. & its not diminishing return. I run 50mm ball nose most of the time, & 2.2kW just won't do it, will trip when the tool bit is less than razor sharp. Also, you know that bigger spindles maintain a more constant RPM with varying cutting load.
Chinese or Hitachi inverters... I can't comment, I'm too poor to buy a Hitachi. Also, I'm too lazy to utilize all the Hitachi feature, enjoy operating the VFD manually, keeps me busy. :)

[bradm]

I agree that moving from 3hp to 4hp, staying within the bounds of a typical supply circuit makes sense. I am questioning whether moving beyond that makes sense, when the costs of the spindle, wiring, VFD (especially if upsized for single phase), and special circuit in the building start to add up quickly.

To be specific, I have run the Huan Yang inverter, and the Hitachi X200 series side by side in the same environment. The HY was essentially an all-frequencies radio jammer; it blocked cell phone and wifi in the room, created audible noise on a cd player, made tuning in a radio impossible, and caused the proximity sensors to be unreliable. The Hitachi does none of the above. Maybe I got a bad HY, but I'm sticking with the Hitachi. :)

[litemover]

Hi Guys,

Thanks for the source of info on the spindle. I really appreciate the discussion here. I may be moving into a commercial building with 3ph fairly soon, so that would make things ok with the electricity. I just have one question, is a 3kw able to cut sheet metal and acrylic at a reasonable rate of speed? Steel and Aluminum? I'm needing to cut aluminum sheet and acrylic. None of it is that thick, but I also want to be able to cut fairly quickly as sometimes the deadlines are a bit unrealistic. An X200 is reasonable on ebay used at the moment. Moving up to a 5hp Hitatchi though it about $680.

Anyhoo, thanks for all the info guys.
Chris

[litemover]

Regarding the spider plate. Mine has no markings... So I've been trying to find datums to measure off of and looking at the spider plate plan, it looks as if one side is further over than the other by about 2mm. Is this deliberate? Just wanted to make sure before I start drilling holes.

Here is my drawing of my spider plate where you'll notice that the hole pattern is not centered.

http://s16.postimg.org/cj91cbd5x/Spider_Plate_Sheet1_page_1.jpg (http://postimg.org/image/t70jet7xd/full/)

[Gerald D]

The laser cuts and marks are symmetrical, but a 2mm variance in bending is normal.

If the spider fits in the carriage, that's the main thing. Spacers/washers are used to fill the clearance. You can pack those on any side you want.

[litemover]

Thanks Gerald. I drilled it and it looks good.

Now I've stumbled across a fantastic price on LAPP Olflex cable with a BLUE outer sheath. But there are some things I need to get input on before going ahead with it. First off it's .75sqmm but I'm only running half coil PK296 B2B sg7.2 which is ~38vish 3.5amp. The LAPP .75mm is rated at <75VDC. Ay thoughts here? Here is a spec on the cable. It's saying that the static is 7.5x bend radius and up to 20x bend radius.


Ölflex EB CY Blue Intrinsically Safe Control Cable (screened)
Olflex® EB CY is a PVC control cable with a blue outer sheath for use in explosive atmospheres with hazard type "i" (intrinsically safe). Complies with DIN EN 60079-14 section 12.2.2 (VDE 0165 Part 1). The copper braid screen is for protection against electrical interference.
Designed in accordance with HD 21.13 that is VDE 0281-13
Conductor: fine wire strand of bare copper to IEC 60228 (VDE 0295) class 5
Core insulation: PVC compound TI2 in accordance with VDE 0281 part 1 (HD 21.1 S3)
Identification: in accordance with HD 186 that is VDE 0293; black cores with white numbers, without green/yellow ground conductor
Wrapping: Insulating plastic
Screen braid of tinned copper, coverage = 85% (nominal value)
Outer sheath: Blue PVC compound TM2 in accordance with HD 21.1 S3 that is VDE 0281 part 1
Electrical properties at 20°C: Nominal voltage <50Vac; <75Vdc
Rated voltage: <50Vac; <75Vdc
Temperature range: -5°C → +70°C (flexible installation); -40°C → +70°C (static installation)
Minimum bending radius: 20 x cable diameter (flexing)
Flame retardant in accordance with IEC 60 332.1
Tested in accordance with VDE 0472 and IEC 60 811-X.X that is VDE 0473
Note
The product is for use in the voltage range:<50Vac and <75Vdc and is therefore not in accordance with the ECD 73/23/EEC (Low Voltage Directive). Compatible connecting glands must be used and correctly installed to meet ATEX requirements.

[litemover]

The spider and Z slide is nearly complete with exception of the gas spring and bracket. I ground down a profile on the plate and it turned out quite well. Then cut the plate and blued it for precision layout. Punched start holes then drilled 3.5mm holes in the plate. Enlarged them to 6.5mm. Countersunk them using my new Bordo Cobalt 20.5mm Countersink. It cut beautifully and quickly but made some ultra fine and sharp swarf that kept lodging itself in my fingers:mad:. My press lost a bit of it's clamp as the holes went on so they progressively got slightly bigger. Lucky it was just a test flatbar until the ground plate comes.
http://s8.postimg.org/t2ohk2u2p/IMG_2139.jpg (http://postimg.org/image/t2ohk2u2p/) http://s8.postimg.org/8smkr73k1/IMG_2140.jpg (http://postimg.org/image/8smkr73k1/)

Transferred the hole pattern to the RHS 50x25x3, tapped to M6, and locked it down with the countersunk allen caps. All went well there, perfect alignment.
http://s8.postimg.org/4q055uytd/IMG_2141.jpg (http://postimg.org/image/4q055uytd/) http://s8.postimg.org/b2fafp1vl/IMG_2143.jpg (http://postimg.org/image/b2fafp1vl/)

Welded the spider plate and instead of having the bearing posts turned I found some collars that exactly matched the posts and they worked well.

My spider didn't have marks so I spent a few hours trying to get a perfect alignment and distance on the spider with my calipers and square. Scribed two lines and used my calipers to get the cross scribes prior to punching them. Measured and it was perfect. Then I tapped the holes in the spider and put the whole thing together. Smooth rolling and all rollers making contact evenly. It's a nice feeling when everything glides smoothly in the end. :D
http://s8.postimg.org/lsybnmq4h/IMG_2147.jpg (http://postimg.org/image/lsybnmq4h/)
Here are some pics of the finished Z slide minus the Spirng and bracket. Also, I haven't welded the nuts on the back yet, but I will do.

Ordered most of my electronics, purchased two contactors, and a 4 pole breaker. Got a great deal on a 40amp 4 pole contractor from Italy for $25 NZD. One from China for a tad more. Next going to get a spindle.
http://s8.postimg.org/n9efjiif5/IMG_2163.jpg (http://postimg.org/image/n9efjiif5/)
Cheers,
Chris
http://s8.postimg.org/euu7hos05/IMG_2152.jpg (http://postimg.org/image/j3yxjuv9d/full/)
upload (http://postimage.org/)
http://s04.flagcounter.com/count/TBm5/bg_FFFFFF/txt_000000/border_CCCCCC/columns_8/maxflags_181/viewers_0/labels_0/pageviews_1/flags_1/ (http://info.flagcounter.com/TBm5)

[smreish]

...Thank looks about right!
Great work Chris.

[litemover]

Thanks Sean.

I found a great price on rack, if i can use mod 1 rack 12mm thick x 15mm high. Is that doable?

[Gerald D]

Yes, that size is okay

[litemover]

Thanks Gerald.

Have one more question about VFDs. I found a good 10hp ABB VFD drive for reasonable, if I buy a 5 hp spindle will I be able to use the 10hp drive for it without problems? Also will Mach3 be able to control the ABB VFD?

Thanks in advance for the feedback on this one.

Chris

[litemover]

Well, I just purchased a 7.5kw 15amp 10hp ABB VFD, the ABB ACS350-03U-15A6-4 with advanced control module and full case for a killer deal at $199USD plus shipping:D. Worth at least $1600. They were going so fast I had to get one, if it don't work out right, I can send it back.

http://i.ebayimg.com/t/ABB-ACS350-03U-15A6-4-Variable-Frequency-Drive-Used-/00/s/MTIwMFgxNjAw/z/HOsAAOxyakdRES1h/$T2eC16FHJF0E9nmFQVJ,BRES1hfD8!~~60_12.JPG

The guy has 2 left if anyone is interested. Link is here: link to ebay auction (http://www.ebay.com/itm/ABB-ACS350-03U-15A6-4-Variable-Frequency-Drive-Used-/251224826791?_trksid=p2047675.m1850&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%2 6asc%3D14292%26meid%3D5404742841343139851%26pid%3D 100011%26prg%3D1095%26rk%3D2%26sd%3D350538035286%2 6)

[domino11]

Hey Chris,
Do you have 3 phase power at the shop or are you going to run a single to three phase inverter for the vfd?

[litemover]

I have 3 phase power, but I read somewhere you can connect this to single phase and get 2/3 power out of it? Is that true? My spindle only draws 10amps at 5hp 4kw.

[danilom]

The number 4 in the model number means 380 - 480 V input voltage
to get that you need voltage between phases so its 3 phase

later in manual they say that 3U in model means
03 = 3-phase (200 - 240V and 380 - 480V)

Do you know if they got a Modbus RTU (RS485) to go with it? :)

[litemover]

That's what I figured, but I do have 3 phase in the upcoming shop so it should be ok. I do not know if it has mod bus, but I did purchase a spindle controller from either PMDX or smoothstepper. Is that going to help? I'll be glad to buy whatever I need to make this VFD work with the Chinese spindle and Mach3.

I assume this is the bit I need to make it work properly? It does not come with it.

[litemover]

I just read in the manual that it does have embedded field bus for control through the RS-232 panel connector. Wil that work?

http://s24.postimg.org/59igec0kl/Screenshot_4_30_13_12_53_PM_3.png (http://postimage.org/)