[randyf1965]

Just wondering if anyone has tried using a timing belt instead of a lead screw like a printer (dot matrix or inkjet) uses to move the z axis? Using a tensioner to tighten the belt and drive with a stepper from one end. I am looking for a alternative to the 64" 5/16" threaded rod (the WHIPMASTER) as I like to call it. Comparing gear rack and a larger acme rod. Also wonder if I could us it on my Y axis on both sides and drive with 1 stepper

Open loop 3/8" .200 XL Neoprene fiberglass cord belt is $2.97/ft from SDP-SI

[ViperTX]

Yes, you can.....and it will also be a whipmaster, plus the additional force you adding to the bearings of the stepper will shorted their life.

[Jason Marsha]

Benny used open ended timing belts on his system without any problems and I think he has servos. To avoid stress on the motor bearings the drive gear is usually on a bearing supported shaft. The motor then drives this shaft via a coupler.

Pictured is a simple 6.25 to 1 setup for a future router. The flat belt will run along the long axis and over the free gear.

Jason

[randyf1965]

I would decouple the stepper from the belt/pulley to avoid the tension force on the stepper.

I don't think the whipping force on the belt would be the same as the rotational force spinning the 5/16-18 rod at 1200 rpms (~66ipm)

Square on right is a stepper connected via a belt to the main drive pulley (quick drawing) The larger rectangle in the middle is the z axis and the smaller rectangle is the connector to tie the belt to the Z-axis. Might have to include a tensioner on the Z-axis or figure out how to make the end pulley adjustable

Will try and make a 3D version... but off to do some Christmas Caroling