[planekrazie]

Ran into a slight problem. I need to use a larger pulley on the main drive to gain some torque. Right now I am using a 10 tooth on the stepper and 30 on the main drive with 4 25 tooth on each corner. Anyone care to give me an idea on what to change. How bout a jack shaft?
Steve

[planekrazie]

Its all done but the left side belt. I ran out of belt so its off to order more.
Some Changes I done at the last min was to make the main drive pulley slightly larger. Say 70 Tooth from a 36 tooth. Man the torque it gives now.
It will push me across the table if I was that stupid to sit on the table :withstupi. I lost some IPMs but 750ipm rapid is awesome in my book for a DIY. The cutting table was off quite a bit soooooo I took what I call elevator bolts ( <--- thats the real name for them) about 50 of them and drilled and tapped the cross braces at 4" intervals, Then took the router and went to the highest point on the braces. Then I set the top of the router bit to top of the bolt and zeroed the z axis. Took the router to everyone after and raised or lowered each to the tip of the bit. Used some thread locker and 2 lock nuts one on the top and bottom. Wala, Flat surface for the cutting board.
Here are some photos.

[planekrazie]

Photo set 2

[planekrazie]

Photo Set #3

[rkd]

Awesome design! What size pulley's did you end up going with for the drive reduction?

[planekrazie]

On the main drive is a 70 tooth xl pulley and on the stepper there is a 15 tooth pulley. It will push you across the table. I still get 1400+ rapids all the way around except the Z. I used a 1/2x10 acme screw.
Steve

[rkd]

Thanks for the reply. Have you been doing lots of cutting with this yet? How are you finding the resolution?

[cncmad]

I must say Steve, my hat comes off to you on a well executed project. It would have to be one of the best designed DIY projects I have seen yet. I am still at the drawing board for my first project and your design has inspired me greatly. Not sure of your profession but I am a fitter and turner (in Australia) and your design appears quite robust and would suit my application well. If I can, I have a few questions for you that may help me on the design of mine.
1. How do the belts perform under load. Do they deflect much?
2. How do the belts wear and is stretching a problem when it comes to the indexing of the gantry (Distance travelled 'v' Distance indexed on stepper motor)
3. Can you fill me in on the software you are using to drive your table as this is an area where I am lacking experience (GREATLY)
4. Where did you source your stepper motors, drivers, ect?
5. If it is not a rude question, what was you budget for this project.

Thanks
Mark!

[planekrazie]

1. How do the belts perform under load. Do they deflect much?
2. How do the belts wear and is stretching a problem when it comes to the indexing of the gantry (Distance travelled 'v' Distance indexed on stepper motor)
3. Can you fill me in on the software you are using to drive your table as this is an area where I am lacking experience (GREATLY)
4. Where did you source your stepper motors, drivers, ect?
5. If it is not a rude question, what was you budget for this project.

Thanks
Mark!

Thanks For the kind words. Asfar as my profession I am just a peeon Production supervisor for a breader and batter Company In Cleveland, Tennessee. I love to work with wood and steel. I am a electronics and Rc Plane hobbiest. I built my 1st CNC router for my planes. It was sold to another member of the zone. I have some photos of it also in another thread Somewhere. As for your questions:
1. I love the belt design. Mine are kevlar reinforced L belting on the X axis.
As far as deflection, I can not see any. No backlash here...
On the Y axis I used the same type of belt ( Kevlar reinforced ) XL Belt.
2. Mach 3 has a "verify axis " When I move it to the max location of the +x and hit the verify. It goes back to the 0,0,0 and then to the location where I hit the verify. As far as stretching, As stated above, The Kevlar reinforced is great. I guess over some time I will have to tighten the belt at the clamp on the gantry.
3. I use Mach3 to run my gcodes. Most codes are done with Vcarve pro.
4. My stepper and controller package is from www.hobbycnc.com
Dave Rigotti is the owner and has some great customer support on his yahoo message board.
5. As far as price..... No one would believe me if I told them that I only have $850.00 USD in this machine.. Here in athens tennessee there is a local salvage yard that has old machines that use any type of linear rails and bearings that you can think of. I go and pull them out of the machine before they scrap them. 250.00 For the controller and steppers. Steel was around 80.00 And a lifetime supply of screws and washers thanks to the maintnance dept at work :rainfro:
If you want some pics of the cnc in detail, Shoot me a pm and let me know where you want.
Later Steve

[la_coterie]

Neat, very nice. not unlike mine
http://www.cnczone.com/forums/showth...9&pp=15&page=4
mines even painted blue (cheap paint on sale)

How do you find the "give" in the belts on the X? trying to push the gantry while it's stationary. I've got wire reinforced belts and still get about 1mm of "give" though I've never noticed it effectingthe machining.
How wide are those belts you're using? I suspect I need to upgrade to wider belts if I could be ars*d

[cavediver]

Steve, Excellent build!!!
You have done a wonderful job.

I have been lurking in the forums while I model my design and would like to include a few ideas form your machine as I work on designing mine (hope this is OK with you).

I have some 45(heavy) and 25 series rails and bearings from a similar source to yours (I’m a field service tech with an automation company) that will be used on each axis.

I am also thinking about using the HobbyCnc same kit, and would like to get your current opinion on your gearing. What final sized pulleys did you settle on for each axis?

How about twisting in the X-Axis driveshaft – “If’ there is any racking to be seen, do you think moving the X-Axis motor to the center of the shaft would help? (equal twist on either side of the driving pulley?)

Any further updates or other idea’s you have learned along this build, I’d love to hear them, and I’m sure others would like too as well.

Congrats again,
John

[rkd]

Did you end up using L belts and pulleys on the X axis with xl on the drive, or xl all the way around?

[farley]

Man that belt looks great . I'm glad I haven't got started yet as this looks beter than rack and pinion.

[farley]

Really like your machine! I've been checking out the Meckmate thread but i think your design is better! Where do you buy that belt by the foot? Do you think roller chain would be just as good?

[planekrazie]

Did you end up using L belts and pulleys on the X axis with xl on the drive, or xl all the way around?

Sorry For the long dely in replys. I used L belt on both sides of the X axis and xl on the Y. I used a acme threaded rod from enco on the Z.
Steve

[planekrazie]

Really like your machine! I've been checking out the Meckmate thread but i think your design is better! Where do you buy that belt by the foot? Do you think roller chain would be just as good?

I got the X belt from a local automatic car wash. Some one ran into the thing and they ordered a new Unit. Lots of belt was left over so It was given to me. The xl belt came from hubbardcnc on ebay. It was about the same cost as mcmastercarr thought. ( didnt find out until I bought )
Oh well... I helped out a fellow cncer.
Steve

[plampasso]

Great design. I like it so much I want to build one just like it.

1. I see that you used 2" X 2" 14awg for the frame, earlier post showed the gantry made from 2" x 2" also but later post showed a solid beam. What material is this made from and what thickness?

2. How far above the table top is the bottom of the gantry?

3. Are the sides of the Gantry and mounts for the steppers made out of 1/4" or 1/2" aluminum?

4. Did you use a 10 tooth gears on all the steppers, 25 tooth gears on all four corners, and a 70 tooth gear as the main drive? Where did you get them from?

5. What size screw for the Z? What size gear did you use on the screw for the Z ?

6. What size is the drive shafts at the front and back of the machine 5/8? Where did you get the bearing plates for those shafts, part numbers?

7. What is the width of the belts?

8. If you were to start over again is there anything you would change about the design?

If you could e-mail me some more detailed pictures that would be great, and if you have any video of the table in action. Thanks in advance for answering my questions. Keep up the great work.

Paul Lampasso

[stepinator]

You're machine turned out great. I found using the belts was the only answer to fast, accurate and affordable axis movement. The results using belts far exceeded my expectations. Nice work and happy cutting!!

[planekrazie]

You're machine turned out great. I found using the belts was the only answer to fast, accurate and affordable axis movement. The results using belts far exceeded my expectations. Nice work and happy cutting!!

Thanks, I love the belt designs. I need to upload some new pics of the 4th axis add on. Still learning how to use it. Id like to see some pics of everyone elses belt driven cnc routers.
I might start up a new thread.
Thanks Steve

[plampasso]

Hello Steve

Great machine. What material did you use for your gantry? Steel? What thickness?

Thanks
Paul