Updated to Rack and Pinion from Chain Drive #62 - Fort Wayne, IN USA [Archive]

scot

Tue 11 May 2010, 20:55

Hello everyone! My name is Scot. I live in Fort Wayne, IN in a repurposed Firestation. We live in the top floor, and my shop is on the ground floor. I worked as a Honda mechanic for quite a few years, but recently moved the business to a building next door, and it is now being run by a friend.
I have been working on a Mechmate for several weeks now with my nephew Collin (user name cmd1991). It is for him and his Dad, and they will be using it primarily to cut cabinet parts. We have a rolling gantry and Y car so far.
I will be posting pictures and more information soon in the "Construction Started" thread.

scot

Tue 11 May 2010, 21:39

I guess I will start posting a few pictures here for now.
The first one shows how we leveled our x tubing with jacks and a level.
Next we measured out our cross piece supports and welded them.

The second picture is happening because we accidently ordered our tubing the wrong length. :eek: oh well:p

The third picture shows our method of cutting the rails. We clamped the angle iron to the inside of our tubing, and held our grinder vertically so we could push down. We used a wood block for the base on our grinder when we started, but ended up switching to a metal one. We found it worth the time to make guards for these grinder setups :cool:

I think If we did it again, I would try the skill saw method. We went through 12 Harbor Freight cutoff discs. I wish I would have known about the perfd Inox discs. It may have been worth it. For the grinding we used 4 or 5 Aluminum oxide discs from Harbour Freight. They seemed to work very well.
Keep in mind that this is a very time consuming project. Collin spent around 4 or 5 days cutting and grinding. What a mess too.

Gerald D

Tue 11 May 2010, 23:45

Welcome Scot, have merged the posts in the Construction started section.

cmd1991

Wed 12 May 2010, 16:07

Here are some pictures of the y car. We still have to make the z plate and mount the spider and all that good stuff.

We finally have a rolling gantry and Y car. Yay for Scot! I was wondering why the holes for the v bearings (on the gantry and Y car) were not 5/16" like the eccentrics? they were closer to 1/2" (We ordered the laser cut parts from cvsupply.com) Was this their fault? Scot actually drilled them out and made bushings. Works nicely, just a little extra work.

You can see we decided to do our leg bracing a little differently. The Legs themselves are 4"x4". Then we used 2"x2" to make the horizontal pieces. We did not use any diagonal braces so we could store stuff underneath if we needed to.

Scot was working on the stops when I left last night.

We have the Motors, Gecko 203vs, 48v power supply, pmdx 122 on the way. Still looking for/pricing wiring. Still having fun!

Codered741

Fri 14 May 2010, 15:59

The Gantry and Y-Car dont use the eccentric bushings. Just an M12 bolt through side plate and the bearing, with shims to make it ride right.

See M1 20 100AB

-Cody

cmd1991

Sat 15 May 2010, 15:00

Hmm, okay guess we missed that.

I'm currently working on the control box design. Can somebody please tell me if I'm thinking right on the e-stops and limit switches? I'm currently thinking I can use N/O (closed when depressed) roller arm limit switches underneath the gantry and Y car. They will roll along the track until they hit the hole we drilled for proximity switches. This way, if anything derails the will act as stop switches also. I am guessing I can add a push button e-stop (mounted on the side of the gantry) in series with these limit switches too? Am I thinking correctly?

Regnar

Sat 15 May 2010, 15:22

Collin, I don't think that the Roller Switch will last very long rolling back and forth. I dont even think they would last a week especially when the dust started getting into them.

You should really read this thread http://mechmate.com/forums/showthread.php?t=584

I want to say the whole proximity part of the system cost less than 125.00

The plans call for 3 estops and again I want to say less than 40 bucks for all of them. If you haven't check out FactoryMation you might want to.

You can live without the limits but I wouldn't get rid of estops. When spending the money just think ease and convenience and safety.

Codered741

Sat 15 May 2010, 19:13

I wouldn't wire the limits and the E-Stop in series, they don't do the same thing!

The limits are used for both homing and derailing, while e-stop kills power to everything in an emergency situation. the way you are proposing, you could trigger a homing sequence, have an emergency, hit the e-stop and Mach would think it hit a limit and reverse trying to get off of it! NOT what you want to happen when you hit the big red button!!!

OR

If you wired the limits in the e-stop circuit, every-time you hit a limit, it shuts off your machine. Not good either.

The PMDX has an input for e-stop, as well as limits. IMHO its best to follow the plans in this department. Wire the E-stop buttons in series to close a contactor, and have one contact close the e-stop circuit. Proxes and relays work great, but mechanical switches do too. Just make sure you get good ones, not the cheesy micro switches. AND you would want N/O switches, so when the gantry jumps/hits limit/wire gets ripped out, the machine stops.

Looks good! What are you using for leveling feet? Are they just bolts?

-Cody

cmd1991

Sun 16 May 2010, 19:56

Thanks guys!
Yes they are 7/8 fine thread bolts. We're still working on the rubber feet.
I think I'm getting a better idea of how this works now. I thought that the limit switches would turn the machine off. I am thinking I will use 2 limit/homing on one end of the X axis (for squaring), one on the opposite end, one on each end of the Y axis, and a touchplate for the Z. Then I will have the e-stops on a second input on the breakout board. Maybe dpst e-stop switches. One pole for the Main power, and one for the breakout board.

Codered741

Sun 16 May 2010, 20:44

do you have something against the proximity switches? They are a tried and true solution, and are really easy to implement.

Just wondering.

And limits will stop the machine, but just in the software. E-Stop should kill the power to the machine, usually through a relay.

IMHO you dont really need to have rubber feet, we are using 3/4" carriage bolts on our table, and they work great!

-Cody

Gerald D

Sun 16 May 2010, 23:19

The rubber feet are only needed if you have a noise problem through the floor. I don't think that many people have their other shop equipment (bandsaw, table saw, planer, etc.) on rubber feet.

Solid bolting to concrete would probably be the best.

cmd1991

Tue 18 May 2010, 19:55

Thanks for all the info guys!

Quick update.
I found a control box from a friend. Yayy! Needs a little touchup, but it was a good price, and he also had the din terminals. I ordered my proximity switches, e-stops, power switch, router relay, etc. I hooked up the breakout board with my demo of mach, and was able to figure out that it DOES work.

Also ordered the Z plate steel, gas shock, as well as some misc nuts and bolts.

cmd1991

Tue 18 May 2010, 19:59

I thought I would give you some pictures of Scot's truck to drool over until next time. He will have to give you the details.

Alan_c

Wed 19 May 2010, 00:32

Wow, '48 Chev, I used to have a Crimson Red one about 20 years ago with a 4.1L straight six - then I got married...(no, not her demand, we needed the money)

KenC

Wed 19 May 2010, 01:20

Lovely lovely piece....

cmd1991

Wed 19 May 2010, 09:59

Sandblasting the supply box for mechmate.

cmd1991

Wed 02 June 2010, 08:07

Okay, I've got some more pictures.

The Beast is now Painted Mechmate Red!!!! (along with the driveway and my pants and shoes) :D

It turned out very nice.

We ordered a Milwaukee 3 1/2 hp router from amazon.com
Scot was modifying the base for it yesterday.

I was able to get the edges ground on the z plate yesterday also.
I bought a 7" blade from Harbour Freight and used the table saw method.
Worked very nicely.

Now I will be concentrating on what to use as an alternative cable carrier.
I am thinking about using 2" flexible drain pipe, and using 3" pvc cut in half as a trough for a shelf. I might use a piece of metal tape fastened to the tube to keep it straight. Any ideas?

Kobus_Joubert

Wed 02 June 2010, 08:20

What sprocket is on that stepper on the last photo ?

cmd1991

Wed 02 June 2010, 08:31

There are actually three sprockets.
One on the motor, and two idle sprockets.
Our machine is going to be chain driven. except on the Z axis.
The chain will be fastened on each end, and the motor will pull the gantry and car.

domino11

Wed 02 June 2010, 12:23

OK this will be the first chain drive. What resolution will you have in the end?

Also did you weld or bolt on your cross bearers to the table tubing?

Kobus_Joubert

Wed 02 June 2010, 12:42

I don't understand most of this mechanical designs, but won't this chain system have a lot of play / backlash / start-stop delay or whatever they call it.

Second question... on the other photo it looks like you are putting the90 deg angle on the plate by GRINDING it against that abrasive wheel. What happens if that wheel gets smaller and smaller ? Just asking and maybe preventing you from throwing a piece of steel away if it is not working out.

cmd1991

Wed 02 June 2010, 13:28

Domino11:
It is #35 chain and we have a 10 tooth sprocket on the stepper. I calculated 533.33 steps per inch. Not the best resolution, but should be good to start with on cabinet parts. We may add a gear reduction later.

We welded our cross bearers.

Kobus_Joubert:
We are hoping there won't be too much backlash. The chain will have tension and will be fastened to bolts at each end so we can adjust it.

I was surprised with the blade I used for grinding the Z plate.
I thought it was shrinking, but when I was done, There was very little difference between the old and new blade.

smreish

Wed 02 June 2010, 17:40

...The chain drive should give you pretty good performance. The only challenge I can think of is your capturing the v-groove wheels and the "drive" pretty well. You most likely will not derail if you have a bit or other similar failure. You may find your going to break something if your not extra vigilant. Otherwise - awesome idea with inexpensive parts.

Kobus_Joubert

Wed 02 June 2010, 23:36

Thanks Collin, I thought that it will wear quickly and then your angle will not be 100%. But it worked and that is all that count's

J.R. Hatcher

Thu 03 June 2010, 07:14

Colin I would grind the sprocket so it doesn't protrude through the chain and can bottom out on the roller. Then allow the chain to lay right against the bottom of the rail and spring load the motor as normal. I can't see a lot of wear or backlash this way. I have been a cabinet maker for 40 years and I don't see any problems with accuracy of cut parts using this setup. The first Shopbots were chain driven.

cmd1991

Thu 03 June 2010, 08:35

I have considered that.
However, I thought that wrapping the chain around 1/2 of the drive sprocket (with idler sprockets) Would give it more contact area since it is such a small sprocket.

cmd1991

Fri 04 June 2010, 19:11

Thanks everyone for the helpful input.
Here is a picture of the z axis and the router base.

We built our router mount based on Cordell's design here http://mechmate.com/forums/showthread.php?t=2570&highlight=milwaukee

Hopefull I can get a lot of work done on the control box tommorrow.

AuS MaDDoG

Sat 05 June 2010, 05:46

Hi Guys!!

I may have missed it, but are you going to weld any bracing into your table?
You might get some movement with mommentum once old MM gets going:D

Cheers & good luck with the build.

Tony.

cmd1991

Tue 08 June 2010, 09:06

Well, we used 3" tubing for our legs with 2" bracing around the bottom. It feels really sturdy. We were not planning on adding any diagonal bracing. I guess we will just have to keep an eye on it.

cmd1991

Sun 20 June 2010, 19:47

Here come the pictures!

First, is a general layout of the control box.
I found a power supply for a server that outputs 48v 19amps. It looks good and it even has a fan built into the end! I also found a nice 12v power supply at a garage sale.

Scot made a nice aluminum standoff for the gecko drives, and breakout board.

The next two pictures show the z assembly.
The only problem we noticed was the shock rubs on the spider plate. Has anybody else had this problem? Maybe our shock has a larger diameter.

More pictures soon.

AuS MaDDoG

Sun 20 June 2010, 20:04

Colin,

Pics look great and all very neat!! I used an 18mm diameter gas shock on our Z axis and found that it fitted without hitting the spider plate. Glad I did not go to a 20mm.

Good luck with the build.
Cheers
Tony.

cmd1991

Sun 20 June 2010, 20:27

Thanks!
Ok, I didn't realize the clearance was that close. It just barely rubs enough to take the paint off.

Gerald D

Sun 20 June 2010, 23:51

Collin, tweak the bracket at the top of the shock to reposition it a bit.

cmd1991

Wed 23 June 2010, 08:46

Okay, thanks Gerald.
We did our first engraving about a week ago, so we know it moves and definitely makes dust. Hooray! I still have yet to cut all the way through a 3/4" piece of wood, but that will come soon. We mounted our control box right on the side of the machine. The pros being less wire to run and being able to move the entire machine when needed. The chain seems to work good. I would like to eventually make some belt drive reductions in the future, but for now it should do what we want it to do. We did some brain storming on drilling adjustable shelf holes, and hinges, and came up with the dual head solution. Videos to come soon.

cmd1991

Wed 23 June 2010, 08:50

Here's one video.

http://www.youtube.com/watch?v=2T8irlQKadk

domino11

Wed 23 June 2010, 16:15

Collin, nice work!

JamesJ

Wed 23 June 2010, 16:22

Looks great! What system are you using to drive the x axis?

smreish

Wed 23 June 2010, 16:36

Another dual Z axis. I like your idea of a drill motor with a 3 position bit indexer. Where ever did you find the collet rotation system? Or am I seeing something different.

...Also really like your chain adjustment system! Simple and taught.

cmd1991

Thu 24 June 2010, 08:09

We are using #35 chain fastened at each end for our "rack" and a 10 tooth sprocket on the stepper.

Smreish, The drill head is out of a Blum minipress hinging machine. There are 5 bits in an "X" One axis has 3 bits in a straight line for adjustable shelf boring, and when you rotate it 90 degrees, the other axis has 3 bits used for drilling holes for our hinges.

cmd1991

Wed 30 June 2010, 21:36

Wow! We have the machine home now. We brought it home last Saturday. We raised it with a winch in Scot's shop, then backed a flatbed underneath it. Then, unloaded it with a forklift at our place. (helpful hint...Make sure you not only have a SPOT in your shop cleared out for this beast, but a PATH to that spot also :D

cmd1991

Wed 30 June 2010, 21:42

The third picture is my Dad and the owner of Wood Creations by Delagrange, Inc. ( www.woodcreationsbydelagrange.com )

So, we have the machine painted, it moves under command, and has the logos applied. We even used it for the first time to cut parts for a real job. Do we qualify for a serial # yet?

Gerald D

Thu 01 July 2010, 05:51

The last photo is a classic! Who is the supervisor? :D
Actually, they are all great pics with all the people milling around. :)

Gerald D

Thu 01 July 2010, 05:56

We even used it for the first time to cut parts for a real job. Do we qualify for a serial # yet?

Any pics of the job,.....or the off-cut? :)

cmd1991

Thu 01 July 2010, 07:12

Thank you!
Can anybody tell that I like taking pictures? :D

Here is the corner hutch we are working on right now.
We used it to route a 45 degree angle on the frame joints, then routed the top, middle, and bottom shelves. I thought I had a video of it cutting them out, but can't find it.

P.S. We had Several supervisors that day.:D

Gerald D

Thu 01 July 2010, 10:28

Give the bloke a serial number! :)

domino11

Thu 01 July 2010, 17:18

Congrats Guys on the machine! It looks awesome. :)

PEU

Thu 01 July 2010, 20:09

Congrats!, Im very curious about your transmission system, when you have time can you post a little video of it? AFAIK its the 1st MM with that movement method.

sailfl

Fri 02 July 2010, 03:48

Collin,

I like that you used tubing instead of C Channel, I like the way you used the Milwaukee router bracket and placed it on the Z. It looks like a very good machine.

My questions is are you going to add dust collection and where are you going to put the pipe for the duct collection?

How about some pictures of small circles (4") cut with the machine. I would like to see the edges. Cut some diamonds on the diagnoal - so that the faces are not on the X or Y axis but run across both axis.

That is what is so great about Gerald's design, a great machine comes out of new ways of building.

Congratulations on an excellent job and machine. Welcome to the club.

MetalHead

Fri 02 July 2010, 04:48

Great looking machine . Yes you do get a number ...... Where did I put that list ??? :D

Gerald D

Fri 02 July 2010, 04:55

I think #62 is next

MetalHead

Fri 02 July 2010, 05:03

:D I was puttin in the number even as you speak :D !!! Congrats on the neat design.. Keep us informed on how those chain drives work.

jhiggins7

Fri 02 July 2010, 05:20

Collin,

Congratulations on a great looking MechMate and Serial #62.:)

Here is the Updated Builder's Log (http://spreadsheets.google.com/ccc?key=0AttqjIPMBEXKcExveGc4d3U0V25zQmMyX1U1eUVhU Xc&hl=en).

Please provide the dimensions of your MechMate for the log.

I guessed at the start date. You mentioned that you had been building for several weeks in mid-May, so I guessed mid-April. This is your entry, so let me know if you want to change the start date. Also, please review the entry and let me know any other changes you would like to make.

cmd1991

Fri 02 July 2010, 08:37

Thank you all very much for the Comments and Ideas.
I will try to get another video of the Chain drive and some of it cutting shapes like "sailfl" suggested.
I think the tubing for the x axis was probably the best idea of the whole project. It wasn't too much more costwise, but seems stronger and easier to work with.
The second best decision, was to use the proximity switches.
The third decision, was probably using the cable chain, and mounting our control box on the side of the table.

Thank you Gerald for the great design and letting everyone use and build off of your plans. I was also very grateful for your advice on many different aspects of the machine found in other threads.

cmd1991

Fri 02 July 2010, 09:05

jhiggins7

Sat 03 July 2010, 04:58

Thanks Collin.

Here is the Updated Builder's Log (http://spreadsheets.google.com/ccc?key=0AttqjIPMBEXKcExveGc4d3U0V25zQmMyX1U1eUVhU Xc&hl=en).

cmd1991

Sat 10 July 2010, 09:16

cmd1991

Sat 10 July 2010, 09:18

Congrats!, Im very curious about your transmission system, when you have time can you post a little video of it? AFAIK its the 1st MM with that movement method.

I finally got this one too :o

http://www.youtube.com/watch?v=0MHl2N8viKc

Kobus_Joubert

Sat 10 July 2010, 09:25

Well done, I am amazed. Please show more detail of the IDLER pulley.

Only problem is if it get stuck it WILL break something, where the Gerald Design will slip.

sailfl

Sat 10 July 2010, 09:30

Collin,

Thanks for cutting the circles and diamonds and the edges look very good.

Great job on your machine.

danilom

Sat 10 July 2010, 11:36

Amazing performance for the chain drive! MM wins again!

Gerald D

Sat 10 July 2010, 12:41

The stepper motor will also "slip" if something is stuck. From that view, the chain is as "safe" as the rack&pinion.

A lot of people use the same principle with a timing belt instead of chain.

WFY

Sat 10 July 2010, 18:11

Hi Collin,
First of all nice job on the machine. One thing to keep in mind on the chain drive is over time the chain will stretch. We used the same type of chain on the inboard racing boat to couple the engine to the prop shaft. After about 6 or eight races we would have to change the the double roller chain for a new one because of play. It is a lot more load than you will get with a MechMate stepper but roller chains do stretch. Just a suggestion - is to do a periodic check on the travel distance compared to the DRO reading.
I hope this suggestion helps to keep the ' Stupid Bunnies ' under control - they seem to run wild at this shop!:D
Buzz #60

krabenaldt

Sun 11 July 2010, 00:13

I noticed the cut quality on the diamond and circle cutouts to be pretty good as far as I could tell from the pictures. Does a chain drive eliminate some of the issues on cut quality by not introducing vibrations from what would seem to be a more rigid system of the rack and pinion? I followed alot the past discussion made regarding poor quality cuts (or chatter), geared motorheads, belt drives, etc. I always thought that vibration or resonance could have been a factor. I do not wish to start a debate all over again but curious if the "give" I saw on the videos with the chain drive softened the vibrations.

I have collected some of the steel and the laser cut parts but have not started my build yet.

Kevin

ws customs

Wed 04 August 2010, 18:09

I have used chain on one of my cncs and it works great with no backlash the black foot cnc s on buildyourcnc.com also use chain to great effect

cmd1991

Fri 13 August 2010, 21:49

WFY,
Thanks for that information. Like you said there's not a lot of load on it, but I wondered too if it will eventually loosen/stretch. I'll keep an eye on it.

krabenaldt,
This is my first cnc ever, so I'm still learning, but it seems like the tensioned chain may help with backlash. On the negative side though, occasionally the chain itself will bounce/shake at certain speeds. I haven't noticed that it drastically affects the cut quality, I would just rather not see it shake. I'm guessing if I could eliminate the direct drive by making belt transmissions, It would make the cuts even more smoother, and hopefully reduce the chain vibration.

ws customs,
buildyourcnc was part of my inspiration for this project.

chunkychips

Fri 20 August 2010, 21:21

Excellent build Collin.

Particularly like the colour. I might have to deviate from MM blue as well .... just let me check that User Agreement again ... :P

I have been wanting to use chain or timing belt for my MM and was wondering, are you relying on gravity and the chain tension to keep the gantry down or do you have a hidden bearing opposing (pushing up) under the x and y rails.

I was thinking that if i used a chain/timing belt i might add a bottom bearing (spring loaded?) to keep things together.

Any comments?

servant74

Sat 21 August 2010, 19:16

What drives going to chain over rack and pinion? Cost? If so, about what kind of difference are we talking?

I can accept 'because I want to' as a valid reason too!

chunkychips

Sat 21 August 2010, 23:19

For me it is primarily cost.

Rack is really expensive in Aus. about 6x more!!

Compare results from one supplier:
$320 + for a 1020mm length of Module 1 10x15mm rack here (http://www.smallparts.com.au/store/item/gr100102110001500cs/gearsracksmodule100/)
to $70 for 2440mm of 5mm GT timing belt 15 mm wide here (http://www.smallparts.com.au/store/item/bg5488150nf/beltstiming5000mmpitchgttruemetric/)
to $47 for 3m of seemingly suitable chain here (http://www.smallparts.com.au/store/item/chr10953057x3048/chainrollermetalsimplex/)

Now I'm not saying these materials are mechanically equivalent (I'm not an engineer) and I'm not saying they represent the best price available. I'm just comparing prices for the three from the same supplier. The difference is massive.

I did notice another post here (http://www.mechmate.com/forums/showthread.php?p=23133&postcount=65) that seems to suggest I can get the rack a LOT cheaper in Aus (~$42/m) so I will have a look this week. If that is the case then I am happy to go with rack as it doesn't deviate from the original design.

KenC

Sun 22 August 2010, 09:49

AU320/m of module 1 rack! That is day light robbery!

cmd1991

Mon 23 August 2010, 14:01

Chunkychips: Glad you like the color! Dad was actually hoping for a little darker red, I thought a nice DARK blue would have looked nice too, but It DOES look good. There are no bearings or anything holding the gantry down, but there is a bearing on the other side of the Y car. Just like the plans call for. In all of our playing, testing, working, etc. we have not had problems with it derailing except for a couple of cases when we ran into something. I don't know about timing belt. I just figured chain would last longer.

servant74:
Part of the reason was cost, (For us it was about $275 savings) and I think there might be less backlash with tensioned chain.

chunkychips

Sun 12 September 2010, 22:58

Collin I have looked over you build a few times now. It continues to impress me.

I had a couple more questions I was hoping you might answer:

1. Did you use the standard motor mounts or did you make your own (they look custom)?
2. What size steel did you use in your legs and bracing?
3. I noticed that you chose not to add diagonal bracing to the legs. Has this caused any problems? Do you notice any instability or resonance especially at higher speeds? ie if you did it all again would you add bracing?

I have been wanting to make full use of the space under my table (mine will be in my garage and space is at a premium) and your design fits the bill. I have seen the other (http://www.mechmate.com/forums/showthread.php?t=272) under table storage solution on the forum but yours appeals more if it works.

Thanks again

scot

Mon 13 September 2010, 08:25

Hi Chunkychips,
This is Scot, Collin's uncle. Collin and I worked together to build this project for their shop. It was a great experiance one thing I do is design fabricate stuff. Said that just so you know this is nothing new for me and that you might have a little more confidence in what we did.
We did use the standard mounting plates but modified them by adding a longer end so they would bolt on level. I think you can tell with that info if not ask again and i'll explain more, Oh yeh we machined a recess for the motor and moved it placement slightly.
The whole table is a redesign only because I saw too many possible problems with welding pull and I was teaching Collin how to weld and I like to make things easy on myself and others.
The box tubing for the table is 3"x8", 3"x6" would be just fine and even 3"x4" would work good, 1/4" thick.
The legs are 3"x3"x 1/4" with 3/4" leveling bolts.
We have no problem at all with table movement. All seems must be completely welded.
If for some reason you just have to have a brace you can put a short one from the upper part of of the leg to the main rail and still have storage. I was worried that welding to the main beam could cause it to bend or pull out of shape so thus the design.
The chain drive works well, I am in the process now building gear reduction boxes for the motors, Collin wants more power.
The tube main beam is the real secret to this design it has much more rigidity.
Hope this helps Nick if there is anything else we can do just ask, Thanks,
Scot

chunkychips

Mon 13 September 2010, 23:40

Thanks for the detailed response Scot and congrats on a great build.

That's some fat steel you're using there. Did you also use 1/4" in the Y beams
and the (2"x2"s ??) around the legs?

scot

Tue 14 September 2010, 07:54

Hi Nick,
We used the recommended size for the y beams we thought that weight was an issue there. After seeing Mech run I think that could be 1/8" It would stableize the downward thrust into the wood by the router. But not necessary if you have hold down bearings, which we don't. I was concerned about motor power too, turns out to be a non issue.
Had to go back and look at the scrap we used 1/8 on the 2x2 I think I would bump that up to 3/16, weight is always an advantage on machinery vibration issues and the like, 10 sheets of plywood underneith will work too.
Thanks for the good comments people look at it and say," what did you build", it looks manufactured to most people.
So thanks too, to the MechMate forum and everyone who helped we enjoyed the build.
Scot

cmd1991

Tue 14 December 2010, 20:24

Okay,
I have some more pictures for your viewing.

The first 2 are of our belt reduction drives.

Here is the link to the place we ordered the belts and gears from.
4 15 tooth gears
4 45 tooth gears
I ordered 5 belts so we would have an extra one.

https://sdp-si.com/eStore/

Part Number Quantity Unit Price Extension
------------------------------------------------------------------------
A 6A 3-15DF03716 4 $10.49/Each $41.96
A 6A 3-45NF03716 4 $17.42/Each $69.68
A 6R 3-054037 5 $5.60/Each $28.00
------------------------------------------------------------------------

Subtotal: $139.64
Shipping: *
Handling: $3.95
Sales Tax ( NY State Only ): $0.00

The plates are 1/2" aluminum, and we ordered the bearings from vxb.com
Scot did all the machining on them.

Now we have much more torque, and don't have to worry about skipped steps.

Now, I am currently working on meeting the electrical requirements for our 15hp vacuum, as well as a 3hp perske spindle. We puchased these from a gentleman on the shopbot forum.

The last photo is of the acrylic door panel I made for the control box.

cmd1991

Tue 14 December 2010, 20:36

Here are some more pictures of some of the stuff we've made.

We cut 9 of the black corner tops
21 sets of the straight cubicle and filing cabinet tops
3 conference room tops
4 table tops and an island in the breakroom
3 smaller tops for the 2nd level breakroom
The last picture is of a wall in the front entrance area.
That's a prototype of this business' logo in the center.
We cut out the top for the reception desk also, but I don't have a good picture of that yet.

We've used the mechmate on several other jobs also, but this is the biggest one we've used it on so far!

MetalHead

Tue 14 December 2010, 21:12

Wow !! Nice work !!!

domino11

Tue 14 December 2010, 21:17

Nice! :)

belmekki

Tue 01 February 2011, 08:31

cmd1991

Fri 04 February 2011, 18:55

Hi there,
excellent job Collin. I have liked your design on the chain drive. I myself interested in it because, as you pointed it , of cost. Rack and pinion are out of price here in Oran where I live. I gathered everything on the mechmate cut pieces and made it as one here in the forum did it before '' the bolted version''. I have got one question:
What are the specs the sprocket tooth and the chain ?
thanks in advance and congratulations
BRAVO

Hello,
The chain is #35 chain.

The sprocket on the stepper motor is 10tooth with a 1/2" bore.

The idlers are 18tooth with a 1/2" bore as well.

I also bought 4 boxes of 10' lengths of chain.

I ordered the sprockets and the chain from surpluscenter.com

Total was $106

cmd1991

Fri 04 February 2011, 19:17

Here is a picture of the finished "JH" logo. We painted it with a high gloss oil based paint.

The second picture is of a curved piece of crown mould.
The customer (fellow cabinet maker) made a curved cabinet, then brought us a block of maple with the same radius as the cabinet. I drew the 3d model in sketchup (free edition) then exported the .stl, and did the cam process with freemill (also freeware). I was not expecting to do this with free software.

We ended up needing to buy a extra long 1/2" straight flute bit due to the height of the mould. I used a .060" stepover. It did need some sanding:D
It wasn't perfect, but the customer needed it pronto, and we decided we would do it for the sake of education :)

Not bad for the first 3d project.

hennie

Fri 04 February 2011, 22:07

You have my attention!

jhiggins7

Sat 05 February 2011, 06:37

Nice work, Colin. Thanks for sharing.

domino11

Sat 05 February 2011, 22:54

Wow, impressive. Did you scan the profile of the existing molding for doing the 3d model? Interested in the process. :)

belmekki

Sun 06 February 2011, 02:36

Very nice job Colin! thank you for the chain and sprockets characteristics. Are these with the pinion reduction you have talked about or is it a standalone transmission setting. Thanks again

cmd1991

Mon 07 February 2011, 06:52

Very nice job Colin! thank you for the chain and sprockets characteristics. Are these with the pinion reduction you have talked about or is it a standalone transmission setting. Thanks again

The last specs are for the chain sprockets only. The belt transmission parts are in post #75.

@ Domino11
That was the trickiest/hardest part of the whole job! I DID trace it on paper then scanned it in, then scaled it to the right dimensions, and imported it to sketchup. However, I still needed to trace that scanned picture with the pencil tool in sketchup. That was trickier than anticipated. The process could be improved somehow.?!? It turned out fairly accurate. The profile wasn't perfect, but that's what practice is for right? :D

cmd1991

Fri 20 May 2011, 06:07

Well folks, The time has come.... As much as I hate to do this....As long as I have put this off....It doesn't change the facts. I've decided to fit her with the rack and pinion according to the original design. :cool: I wanted the chain to work. I really did! But, There were some things I didn't like that I decided were not worth "playing with" in a production shop. :D While I think it would work, and be a low cost solution for a hobby user, etc. I was having problems with the chain stretching and binding up the steppers. The cost was not significant enough to prevent us from just doing it like everybody else. I ordered all the parts and had it working again with just under 2 days of down time. Side bonus was that I got a welder out of the deal. :D

We also got the vacuum all hooked up. I divided the table up into 6 zones. Let me tell you. "That table works nice!"

The spindle is also hooked up. Did I mention I've been learning about 3 phase electricity lately?

I Built my own Rotary phase converter for the 15hp vacuum. Fun ;)
I might post pictures of that later on.

I also attached a picture of one of 25 entertainment center that we just finished. We used it to cut the top and bottom, the shelf in the middle, and the bendable plywood for the face.

The rocking chair is a project I'm taking on for an amish friend. :p

P.S. I'm sure some of you could have told me the chain wasn't the best idea.
Please, let me know what you were thinking. I won't be offended. :o

Kobus_Joubert

Fri 20 May 2011, 06:15

Looking good Colin.. Glad you are honest about the chain thing....and are happy with the original design. In my 3 years I have see a lot of people with some bright ideas. Some locals that I assisted also tried some modifications.... some of them are still not finished after 2 years of building. I have always said to them to keep to the original design as it worked out well for me.
I will say nothing about your chain attempt....too afraid of venom spitting okes on the other side of the world..:D you know what I mean...

sailfl

Fri 20 May 2011, 07:32

Collin,

You gave it a shot and it didn't work the way you wanted it to work. It is better to try than to wonder if it would have work. Thanks for sharing you experiment.

We all learn from others.

bradm

Fri 20 May 2011, 08:34

Colin, I don't think you're going to get any "I told you so" responses; many of us were pulling for it to work, and we appreciate the feedback on the results. "Failed" experiments are often more educational than "successful" ones.

With the understanding that you've moved on for good reasons (like running a business), I'd like to know if you feel that some kind of dynamic chain tensioner such as a spring or large weight could work, or if other issues render this approach dead.

Regnar

Fri 20 May 2011, 11:34

Collins,

You win some and you loose some. I will never fault anyone for trying something different to meet the needs at the time. I think it is great that you were able to come online and share your experience with everyone here even if it didnt meet your needs.

The entertainment centers do have me scratching my head though. They look great but is the TV of center or is the black area for components and the Tv sits on top?

Gerald D

Fri 20 May 2011, 11:44

Hey, give the man a number! :)

cmd1991

Fri 20 May 2011, 12:15

Haha, Thanks Gerald! Do I get #62b or something?

@ Brad
Scot had many ideas for making the chain work better too. A high tension spring may work. I Don't think there would be many problems with it on a light duty machine such as a plasma cutter, laser, etc. The Chain needs a lot of tension to eliminate any backlash, and to eliminate that, you basically are going to end up with a stretched chain. However, on a laser or plasma, you could use a lighter chain (like #25) similar to the machines at buildyourcnc.com and it might work very well. I was also thinking that maybe if you fastened the chain to the gantry and made a loop with the steppers on the end of the machine you would eliminate some sprockets too. But, that would be drastically altering the design of the Mechmate. :eek:

It's also good to remind ourselves that it DID work for about 10 months of moderate to heavy usage.

@ Regnar
The entertainment centers get a granite top on them yet, then the TV sets on top, and the components go inside.

aussie_mick

Fri 20 May 2011, 17:36

Very nice machine. Love the colour as well.

I am only just starting my build but I do like your table.

keep up the excellent work.

michael

louloute30

Sat 21 May 2011, 11:11

Hello collins.

I am french, excuse me for my bad english.

I build my CNC based mechmate, and I wanted to try chain. But I wanted to put the chain on a bar to improve tension and use it as-rack:

http://llcorp.free.fr/autres/SDC12069b.jpg
http://llcorp.free.fr/autres/SDC12070b.jpg

I am disappointed... The chain seemed to work well on videos.

PS: I difusion photos of my CNC once completed.

skillalot

Sat 21 May 2011, 13:20

by the way, using a chain as a rack&pinion isn't as accurate as normal rack&pinion, cause of some play.
But if you do want to use chains, then this is the only way.

If you use a chaindrive for positioning systems, and work with chainwheels, be aware of the polygon effect when using chainwheels. Chainwheels are not perfect circles, but act like polygons, and will give positioning errors!

scot

Sat 21 May 2011, 17:57

Hey you guys,
I think Collin is being a little hard on the chain drive. It did work very well for several months under true commercial conditions and was still working very well before the change to the rack drive. I wouldn't say it was a failure just that it has it's limitations. I think for home hobby use it is an excellent way to go.
What do you think Collin? Am i being stubborn?
Louloute30 that is a very fine looking machine let us know when it's running.
Thanks, Scot

cmd1991

Sun 22 May 2011, 07:02

Exactly,
I'm not writing it off as a total failure. I Did say that it did work fine for quite a while. I think there are a few options one could try to improve the idea. I simply didn't want to "experiment" with mine right now. But, if I had the time and needed to build another one, I would definitely try some other ideas with the chain.

@ Skillalot
The sprockets not being perfectly round makes sense. I kind of figured as much wich is why I suggested that maybe a loop with the chain attached to the gantry would be better.