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  #1  
Old Sun 27 April 2008, 15:41
dmoore
Just call me:
 
truecnc.com - Houston, Texas

Thread was closed and archived on David's request approx end-June 2008. Due to some later friction, I took away his posting privileges. On 30 July it transpired that he had re-invented himself as TrueCNC. A new thread on TrueCNC was moved to the bottom of this thread . . . .

Let me first introduce myself - I am David and I live in Houston Texas (actually near the Woodlands), in the US. I am a fulltime software engineer for a large chemical company. In my spare time, I build mostly art projects - art cars and sculptures in metal. In the fall of 2007, I finished my new 1,300 sq/ft workshop that now allowed me to have enough space to pursue CNC. I spent tons of time on cnczone.com looking at all the options for a plasma/router combo table. I came along the plans for the MechMate but I knew that I would have a long road to go down with just the CAD/CAM/Mach 3 and general terminology of CNC. So, I saved off the MechMate plans and decided that I would build a smaller MDF based CNC machine and see how well that worked and if I could master the necessary skills. Well, I did build the smaller CNC machine and faired pretty well (see attached). I was amazed at what I could do with such a basic machine.

I tried to think ahead and purchase MechMate items that could be transferred over - the PMDX, the Gecko's, Mach3, etc (see attached). Well the time has come to build the MechMate. I started like I think most people do - printing out all the plans and pouring over them until I felt I had a pretty good grasp on how everything went together (I highly recommend printing them on 11"x17" paper in landscape). Next was to assemble a bill of materials. There were a few attempts at a BOM but they were a bit short on detail so I decided to create a highly detailed BOM (see attached) with every washer, bolt, nut, motor, wire, etc - everything. That took about 30 hours of researching, reviewing it against the plans and researching vendors. I currently have ordered about 4,000$ and expect the total (excluding software, Gecko's, computer, etc) for the table (including motors, sensors) to come in at about 4,500$ to 5,000$. I will be releasing the complete BOM once I complete my machine and verify that everything listed is complete and exact.

Continued in next post...

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #2  
Old Sun 27 April 2008, 16:17
dmoore
Just call me:
 
Ordering Parts...Steel...

I started out by ordering as many of the parts as I could. I personally expect that the research and ordering of parts is as much as 25% of the total build time - we'll see. I am trying to stay as close to the plans as possible but I've decided to deviate from the plans in the following areas:
  • Legs - Instead of channel, I am using 2"x2" box tube
  • Cross Bearers - I will be bolting instead of welding due to weight issues (and I have to move in 5 years)
  • Rails - I will be using ground angle, though it's dimensions will differ from the plans (not Gerald approved)
  • Gantry Tube - I will likely be welding the Y rails to the gantry tube instead of bolting as Gerald did in his orginal MechMate

I will be building with the following options:
  • Optional X-Axis Chains
  • Optional Proximity Sensors (18mm instead of 12mm)
  • Geared motors with 30 tooth pinion
  • Milled/Ground Angle for rails

My first purchase was steel. This seems to be were the most variability occurs - steel is a local purchase and varies in price and avaiaiblity on a vendor by vendor basis. There are a number of steel vendors in Houston - most of them cater to companies but one is more of a "wal-mart" of steel and sells in single stick quanities without any minimum and are even open on Saturday. Of course they are a bit more expensive but they usually have what you want and it's easy to get. SSS Steel is my steel vendor (www.sss-steel.com). They also have a great reference of common US steel sizes here: http://www.sss-steel.com/front/frReference.asp . Here are some photos of my steel order and my special trailer that I use to bring home full 20' sticks of steel:

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #3  
Old Sun 27 April 2008, 16:37
dmoore
Just call me:
 
Ordering...Misc Parts...

Here are photos of my other parts. I'm still short the rack, motors and paint but everything else is here. I ordered my laser cut "full options" kit (see below) from jbmclain (Joe) in Alabama for $420 (including shipping), including non-v groove bearings with the geared motor option. Highly recommend Joe if he is still doing group buys on parts.

I ordered nearly all my bolts, nuts and washers from www.boltdepot.com. I ordered everything except for the carriage bolts and nuts/bolts for the skate in stainless steel insted of zinc finish. It was only about 90$ for all the nuts and bolts (see below). I highly recommend them - I will have each of the part numbers from them (in stainless) in the BOM. They ship quick, the price is good, you can purchase quanities as small as 1 and they package EACH type of bolt/nut/washer in a seperate bag with the description and part number - which the BOM has a cross reference back to the specific page the parts are used on.

I ordered most of the misc parts like the cable management, springs, gears, etc from McMaster-Carr. They ship quick, the quality is always the best and the website is super easy to use - the downside is you pay for what you get. Most of the stuff is brand name - the gears are Boston Gear, the cable chain is Igus and so on. I understand they are not so great when it comes to shipments outside the US, but inside the US - el premo. In the photo (see below) you will notice that I went with adjustable, non-skid feet with insert for the 2x2" legs I've decided to go with.

The remainder of the items came from Automation Overstock (www.automation-overstock.com), Factorymation (www.factorymation.com), ACE hardware outlet (www.acehardwareoutlet.com), WT Tool (www.wttool.com), Superior Bearing (ww.superiorbearing.com) and K2CNC (www.k2cnc.com) - all shown below.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #4  
Old Sun 27 April 2008, 16:47
dmoore
Just call me:
 
Cutting cross bearer - 10 10 302 S

I started with cutting the cross bearers for the support board. I used a 14" chop saw and cut them at the suggested 60 degree angle. I cut one and then used it as a pattern for the remainder of the cuts and it came out pretty good. I did have to re-set the circuit breaker about 50 times but they did cut - total time was about 3 hours. Another 30 minutes or so to clean up the welds. See photos below.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #5  
Old Sun 27 April 2008, 19:15
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
I'm Jealous. You found a steel vendor locally that had MC series ship building channel. Very square, very straight, very heavy My choice for the next build for certain. I just like the wider flanges.
I would appear you have prepared for your build quite well. Good luck.
Sean
  #6  
Old Mon 28 April 2008, 10:26
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
David,

WOW!!! I wish I was half that organized. Best of luck. I think you are wise to try to stick closely to Gerald's plans. I never intentionally deviated. That's a lie. I deviated in one area because I thought I knew how to do it better and it has caused me grief ever since. Every square inch of this design was thoroughly considered by him and I don't believe it can be improved.

Just out of curiosity, why are you welding the Y rails to the gantry? I wouldn't recommend it because making adjustments will be impossible. And you are definitely going to need to make adjustments. Bolting them was a piece of cake and they're rock solid.

I love your trailer and shop. Good luck with the build.
  #7  
Old Mon 28 April 2008, 11:35
dmoore
Just call me:
 
Quote:
Originally Posted by Doug_Ford View Post
Every square inch of this design was thoroughly considered by him and I don't believe it can be improved.
I would say that you are completely correct. Of course needs drive the design - Gerald designed the MechMate for himself and around those needs he had. Gerald has been nice enough to adjust the design to be flexible to meet more needs that originally designed for - issues like X, Y and Z lengths/height, cable management, local availability of parts, speed and torque, etc. He has even made great efforts in adjusting the design for availability of skills and tools (rails). Though I think to say it's not likely the design can be improved upon isn't completely accurate. Think - pull top soda cans, cars, pretty much everything on the internet, etc. There is often room for improvement in a design that meets a specific need.

Quote:
Originally Posted by Doug_Ford View Post
Just out of curiosity, why are you welding the Y rails to the gantry?
Why did adjustments need to be made? If the rails are parallel, wouldn't the adjustment be made in the y-Car shims?

Quote:
Originally Posted by Doug_Ford View Post
I love your trailer and shop. Good luck with the build.
Thanks - It was nice to move up from my 600 sq/ft workshop to 1,300 sq/ft with attic storage. I do worry about how much junk I will accumulate in the coming years to fill the space and how I move that to the next house.
  #8  
Old Mon 28 April 2008, 11:40
dmoore
Just call me:
 
Quote:
Originally Posted by smreish View Post
I'm Jealous. You found a steel vendor locally that had MC series ship building channel. Very square, very straight, very heavy My choice for the next build for certain. I just like the wider flanges.
You are correct on the MC channel - it is only .5 degrees off from 90. I purchased that single channel from www.intselsteel.com (a division of my normal steel place, SSS Steel. They have places in Houston and San Antonio Texas. I guess Houston is somewhat blessed since we have so much industry south and east of Houston.
  #9  
Old Mon 28 April 2008, 12:50
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Dave, after I welded the rails to the gantry, the whole assembly was put into a huge planer/grinder which ground the rails parallel to each other.
  #10  
Old Mon 28 April 2008, 19:02
CabntMkr
Just call me: Peter
 
Brunswick (Maine)
United States of America
Quote:
Originally Posted by dmoore View Post


Thanks - It was nice to move up from my 600 sq/ft workshop to 1,300 sq/ft with attic storage. I do worry about how much junk I will accumulate in the coming years to fill the space and how I move that to the next house.
I haven't posted yet on these forums. But i just have to respond. I'd be happy to come down to Texas to take any "junk" off your hands my friend. You're off to a beautiful start, I'm going to keep my eye on you. Hope to start one of my own before too long.
regards, and good luck
Peter
  #11  
Old Mon 28 April 2008, 23:38
dmoore
Just call me:
 
Auctions.. your path to all things crap

Quote:
Originally Posted by CabntMkr View Post
I haven't posted yet on these forums. But i just have to respond. I'd be happy to come down to Texas to take any "junk" off your hands my friend.
I'm sure they have plenty of junk near you. I'm always on the lookout for good deals and I've found plenty of them over the years. Most of my best deals come from business auctions. I may only go to one "good" auction a year where I walk away with items for pennies on the dollar. Some of my best finds are most of my entire hardware store nut/bolt/washer/screws collection - all for $350 (see below). Or the warehouse rack I use for my steel/materials storage and work bench, about 25ft worth (see below) - $1000. Another good deal was all the lab cabinets in my current shop - 18ga steel with tempered glass fronts - $250 (see below). And the best purchase I've made recently was the roll around "bat cart" I use for my CNC control machine - it's a medical computer and thus it's all grounded/surge protected/shielded, has more aluminum in it than I paid for it, came with a touch screen LCD and even had a $1000 (on ebay) digitizer that works with Rino... all for $225 (show in post #1).

Search around in the auctions - I usually can find enough to sell on ebay or craigslist to cover the items I end up keeping. Plus, I'm starting to see a bit more good stuff going to auction now than in the past few years.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #12  
Old Tue 29 April 2008, 10:29
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Quote:
Originally Posted by dmoore View Post
Why did adjustments need to be made? If the rails are parallel, wouldn't the adjustment be made in the y-Car shims?
Lot's of things seem like a good idea before you do them. The point I'm trying to make is that Gerald is not some "mechanical engineer wannabe" who slapped these plans together in a few weeks. He's the genuine article with decades of experience in his career field designing and building mechanical devices.

Right now, lots of guys reading this forum are probably looking at some of the parts or reading some of the processes Gerald's recommending and wondering why? Well, I can tell you that more than once, when you actually start putting the parts together, you're going to understand why he designed things the way he did and you're going to get a big grin on your face.

I'm not a mechanical engineer but I do know a few things about welding, machining, and turning wrenches and I've built a MM. I wouldn't deviate from anything Gerald recommends.

Last edited by Doug_Ford; Tue 29 April 2008 at 10:33..
  #13  
Old Tue 29 April 2008, 10:43
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Okay, let's not discuss me too much!

No home, or average factory, will be able to weld the rails on straight. It might start straight before welding, but after welding it will be crooked. That is just the nature of typical welding. If your rails are straight before and after welding, the welding is very weak because there was not enough heat to fuse the metal. Good welding WILL distort the rails/gantry tubes.
  #14  
Old Tue 29 April 2008, 22:50
dmoore
Just call me:
 
Quote:
Originally Posted by Doug_Ford View Post
Right now, lots of guys reading this forum are probably looking at some of the parts or reading some of the processes Gerald's recommending and wondering why? Well, I can tell you that more than once, when you actually start putting the parts together, you're going to understand why he designed things the way he did and you're going to get a big grin on your face.
Doug - I trust in faith on some thing, others I'm more along the line of "trust but verify". I believe behind every good technical design is sound logic. For the same reason I wouldn't tell a customer "just trust me - I've been working with this product for 15 years" - I provide them the reasoning behind my decision.

This is now a mute issue - Gerald has provide an excellent reason why (see above) he wouldn't weld the rail to the gantry tube. I think that is an excellent reason to make the extra effort to bolt as opposed to weld the Y rails.

Doug, I can already see based on reading just about every post on the forum that nearly every design decision is backed up with real work understanding. I sometimes think we can learn more from what doesn't work as what does work. It's great to see people post dead end roads they went down and projects that didn't work - this helps everyone understand how we arrived at the "right" solution. I'll be posting a few of my mistakes later....

Thanks!
david
  #15  
Old Wed 30 April 2008, 12:07
dmoore
Just call me:
 
There is no shortcut...

Well I've given up on welding the Y rails to the gantry tube and now I'm going to bite the bullet and buy the materials needed to properly cut the rails down to the required 1.1" as my steel supplier doesn't sell the 2"x1 1/4"x1/4" angle. The Aluminum and steel rail combo isn't really any cheaper either, even with tools.

As to the progress... I've drilled all the support bearers. Since I am building a bolt together table, I've drilled 1/2" holes for bolts through the support bearers for attachment to the flange of the main beams. I also stamped identification numbers so if in the future I have to reassemble it, I can get it in the right order. Total time to measure, stamp, punch, drill and then redrill was about 2.5 hours. Here's a tip (I suspect that most people may know..) when measuring out the holes for the outer and inner (on center line of the channel) - find the center and set that on your caliper. Drag the caliper along the outside edge of the channel, scoring a line.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #16  
Old Wed 30 April 2008, 13:14
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
wow...you drilled that by hand and not a drill press? You must have had your wheaties today
  #17  
Old Wed 30 April 2008, 16:53
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
David,

What is the stuff in the yellow aerisol can?
  #18  
Old Wed 30 April 2008, 19:09
skypoke
Just call me: Chuck
 
Port Aransas
United States of America
David,

In hindsight, I'd recommend going with the mfg. track and alum angles. I did not, however, use "the skate" and maybe my take would be different had I done so. You might also want to check the spec on the angle, I don't think it's 2" but 2.5". I ended up with many boring hours invested in grinding angle for a 6' X 20' machine.

Interesting place the Woodlands. My wife and I were one of the first residents there back when it was just hollowed out from the pines. We still have our place in Montgomery but have lived in Port Aransas for the last 15 years. Drop by and visit if you're down this way....

Chuck
  #19  
Old Wed 30 April 2008, 23:36
dmoore
Just call me:
 
Quote:
Originally Posted by sailfl View Post
What is the stuff in the yellow aerisol can?
It's drill lubricant.

Quote:
Originally Posted by sailfl View Post
wow...you drilled that by hand and not a drill press? You must have had your wheaties today
I have a drill press but it was easier to leave all the channels on the table and drill them with an corded drill. With the drill lubricant, you can get nice large chips so it doesn't take long and the holes for the support board didn't need drill press accuracy.

Thanks,
david
  #20  
Old Wed 30 April 2008, 23:43
dmoore
Just call me:
 
Quote:
Originally Posted by skypoke View Post
In hindsight, I'd recommend going with the mfg. track and alum angles. I did not, however, use "the skate" and maybe my take would be different had I done so. You might also want to check the spec on the angle, I don't think it's 2" but 2.5". I ended up with many boring hours invested in grinding angle for a 6' X 20' machine.
I can only imagine how long it takes to do rails on a 6' x 20' machine. What do you do with such a large machine?

Quote:
Originally Posted by skypoke View Post
Interesting place the Woodlands. My wife and I were one of the first residents there back when it was just hollowed out from the pines.
I used to live inside the 610 loop but the company I work for moved from downtown to the Woodlands. I really liked being in-town but it means giving up no less than an hour of your day to the commute. So, we gave in and moved near the Woodlands (I don't think the Woodlands is too keen on routers running at 10pm at night).
  #21  
Old Thu 01 May 2008, 06:38
skypoke
Just call me: Chuck
 
Port Aransas
United States of America
The larger table is to accommodate 20' sheets of marine grade aluminum. My interest in the Mechmate was sparked by a prior building experience. We had a 30' alloy power catamaran (offshore fishing boat) designed by a naval arch. in New Zealand. The digitized cut files were emailed to us then to a cutting service in New Orleans. They cut the parts on a plasma cutter. Long story short, we now own a fantastic vessel which we built over a 1.5 year period. I would like to have a 40 foot table but don't have the material handling capacities to feed such a beast.

We will build some smaller craft when we have the cutting capabilities. My interest has turned to hydrofoil supported catamarans and the Mech will also give us the ability to mill some of the larger airfoil surfaces necessary to const the foils. There may also be some experimental aircraft components sneaking their way onto the table.

I've been a lurker on this forum for a while. When I get the shop cleaned up a bit will shoot a few shots of progress on the table and maybe a couple of the boat.

Chuck
  #22  
Old Sat 03 May 2008, 23:14
dmoore
Just call me:
 
M1 30 224 T - Turned the Hold-Down Idler Stub Shaft

Today I turned the hold-down idler stub shaft. I'm happy to say that my first ever attempt at turning turned out ok. I used a cheap Harbor Freight 7x10 lathe: http://www.harborfreight.com/cpi/cta...emnumber=93212. I turned mine a little to loose so that the press fit was more like a push fit so I tapped a hole and put on a fender washer to make sure it stayed in place. Photos below.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #23  
Old Sat 03 May 2008, 23:40
dmoore
Just call me:
 
10 10 322 W - Cutting the longitudnal beam

A few suggestions on cutting the main beam:
  • Don't use a plasma cutter - the arc wanders too much
  • Use an 1/8" metal cutting disk (or maybe 10)
  • Use a right-angle grinder 10amps or better, the 7amp units don't cut it
  • Make sure to have corse grinding wheels
  • Watch your toes and fingers if you are handling the beams by hand
  • Be sure to wear a dust mask

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #24  
Old Sat 03 May 2008, 23:43
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Those thin Pferd disks in the small Bosch grinder will also do it as easily and quickly as the bigger grinder with the thicker disks.

Hey, havn't you just bought a metal saw?
  #25  
Old Sat 03 May 2008, 23:52
dmoore
Just call me:
 
10 10 320 W - Main Beam Closing Plates

I scrounged around and found some 5 1/2" x 1/4" plate and then trimmed it down to the 3.5" width to close in my beams. Cutting them wasn't a big deal but the welding, and dressing took about an hour to get them really clean. I used a corse grinding wheel for the first run and then a flap disk to smooth it all out. I'll finish the small gaps on the inside later with bondo to obtain a completely smooth finish. Then, when I was done, I used my belt sander to clean off some of the mill scale and rust.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #26  
Old Sun 04 May 2008, 00:14
dmoore
Just call me:
 
10 10 300 W - Attaching the support bearers to the main beam (bolted, not welded)

I'm bolting on my support bearers to the main beam instead of welding them on. I'm using 1/2" bolts on mine. Shown in the photos is layout of the support bearers, making sure to off set to the proper side. I then clamped on the end cross bearers and measured everything and then laid in the other cross bearers. I then used a transfer punch to mark the main beams from the existing 1/2" holes on the bearers. I then drilled a pilot hole and then the 1/2" holes. Be sure to use plenty of cutting fluid and a corded drill. I then bolted the centers in and then drilled and bolted in the remaining ends.

I did make one mistake - I measured off the edges of the main beams to line up the edges of the support bearers, where I should have added 1/4" to each side. Nothing major.

All said and done, it turned out completely square and parrallel.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #27  
Old Sun 04 May 2008, 05:48
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Very nice David.
  #28  
Old Sun 04 May 2008, 17:48
dmoore
Just call me:
 
Quote:
Originally Posted by dmoore View Post
I also stamped identification numbers so if in the future I have to reassemble it, I can get it in the right order.
Note to anyone building a bolt together machine - I HIGHLY recommend stamping the cross bearers and the main beam so that you can properly rebuild it later (or when you take it apart to paint). I'd recommend stamping the numbers/letters so they are visable from the top when asembling. Also be sure to mark a Left/Right or A/B so you can determine which side the bearer is attached to.
  #29  
Old Sun 04 May 2008, 21:23
dmoore
Just call me:
 
Finishing up the support structure...

For the legs I elected to use 2" x 2" x .120" wall tubing since I feel it looks a little more finished and I didn't mind purchasing another type of steel. More importantly, it allows me to use these nifty little nylon inserts from McMaster-Carr (60945K31) and these really nice self leveling feet (6111K373) also from McMaster-Carr.

For the bracing, I am using 2" OD x .083" wall tubing. For the tube on tube action I am fish mouthing the joints using paper templates.

To crush the ends where the tube meets the beam and legs, I used my shop vice. Does anyone have suggestions on a better way to form the crushed/oval ends?

Even though the cross bearers are bolted, I will be welding the side supports back on after I paint it. The tinking is - if I need to disassemble it in the future, I can just cut off the side supports, move it and then re-weld it upon reassembly. The main beams with the legs and supports is liftable my one person, so with the boltable cross bearers, it makes the MechMate "somewhat" portable.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
  #30  
Old Sun 04 May 2008, 21:44
dmoore
Just call me:
 
Moving the Monster!

I finished the legs and support structure, so now it's time to flip it over and reassemble it. I propped up one main beam with my workbench and then with the two end cross bearers attached to the other beam, I lifted it upright and then attached it to the other beam. Once both were attached, I "walked" it crab-style into position where I squared it up and then attached all the remaining cross bearers. All done it was within 1/4" square.

Last edited by dmoore; Wed 07 May 2008 at 08:18..
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