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couple questions about timing belt pulleys



brucer
02-07-2012, 01:16 AM
ok , i have my racks ordered from moore gear, that hurt, cost $145 to my door.. now i need to order timing pulleys...

in emc2 and mach3 does the pitch of the pulleys matter, or can i use any pitch i want and it be configurable in the software, or is the software limited in values you can input into it..

the reason i'm asking is i'm thinking of going to the htd5 pulleys, they use a 15mm wide belt with a .1961 pitch, want to use a 1/2" belt because a friend can order them through his work and they wont cost anything...

the other choice would be to use the xl timing pulleys and they have the .2 pitch, but they use the small 3/8 belt, the 3/3 belt seems kind of light duty to me..


any help would be great guys..

Thanks

Gadget
02-07-2012, 04:00 AM
Pitch doesn't matter. It all comes down to how many turns of the motor shaft equals one inch linear travel.

brucer
02-07-2012, 12:27 PM
do you think the xl belts (3/8 belts) would be strong enough?
I'm guessing they would be since the cncrouterparts design uses them and my design is somewhat close to theirs but probably heavier.

Gadget
02-07-2012, 01:08 PM
That's what I use on my X axis Bruce (3/8 belt). I have a one to one ratio between the motor and lead screws. There's a lead screw on each side. The screws are 5tpi triple start. I'm still on the same belt and have done both plasma and router operations. I've even milled aluminum with this setup.

brucer
02-08-2012, 02:37 AM
thanks gadget...

XL belts and pulleys it will be then.. I think i'm going to go with 3:1 reduction, and I plan on having a extra set of pulleys on hand to go to 4:1 if I need more torque for some reason, a friend can get the 4:1 pulleys for free but not the 3:1 pulleys, I'll have to make bushings for them because they are 1/2" bore, motor is 1/4" shaft and I'm using 3/8 ejector pins for the driveshafts, the ejector pins were free..

the gear racks and the timing belt pulleys are pretty expensive, I think it will be worth it in the long run though.

soon as this stuff comes in the mail It'll give me a good stockpile of parts and I'll get back to work on the project log, i'll post some pics of the parts when they get here.


thanks again gadget