9mm GT2 Belts - Parts and Tools

It is stupid to ask again, since your pulleys were mated to them, but your NEMA23 shaft also measures 8mm?

I thought that Inventables only stocked 1/4" shaft NEMA23s. It seems you were (un)lucky to be part of a non-1/4" batch.

Try contacting them directly to see if they would replace or trade-in the 8mm ones with 1/4" ones.

I’ll check again at lunchtime.

I grabbed the new OB pulleys this AM, walked out to the garage, tried to stick the new pulley on the Nema23, found it was too small, said some bad words, put both the XC pulley and the new pulley in my pocket and grabbed a caliper here at work.

Not sure what’s happening, but maybe I just need a hammer :smile:

@AngusMcleod was 100% correct.

The pulley I grabbed was the one for the Z axis ACME, and not for the stepper, so I was measuring the bore of the wrong pulley from the XC parts…

Crisis averted !

Thanks Angus!

lol well done …

About to jump into my own X carve build and already ordered the 9mm belts, idlers pulleys etc. Anyone identified a source for 9mm clips, or a resource that will fabricate them (or have any extras laying around?) :smile:

I have not tried it myself but I believe someone did and it appears to be enough material for it. You can just take small file and widen the gap in existing ones.

Someone else made their own on a 3D printer. Personally, I’d just get a small piece of metal, mill the slots (maybe even 3 instead of 2, since many believe 3 slots make the belt-weaving process more secure) and then use a small brake or a hammer and vice to make the L…

So far, I have only seen people build custom clips.
The clips are either (in order of popularity):

  • CNC milled or fabricated a new “flat” or “L” Clip
  • 3D Printed a clip
  • Widening the original X-Carve clips

I don’t have quite enough data yet to make a solid recommendation, but instead of 9mm GT2 belts, I upgraded to GT3 belts and pulleys from OpenBuilds. The GT3 belts are 6mm, so you can use the existing clips and idlers, but the teeth are deeper and bite quite a bit better (IMHO) than the stock GT2 belts did.

You may want to weigh the costs of 9mm belts and new idlers versus GT3 belt and new pulleys, then you don’t have to muck with the clips…

That is what I did. Took flat bar Home Depot piece and on drill press just did bunch of holes in a row. They worked well, once my machine was all working fine I took rest of the stock and milled clips using xcarve and replaced.

when you upgrades the belts and pulleys was their any spacing issues or need of different sized screw ?

A 9mm GT2 belt stretches less than a 6mm. Belt backlash comes from the belt stretching under the load that is needed to start te gantry moving, so less stretch means less backlash. Less backlash is greater accuracy.

As the Y axis have 4 wheels and less friction than the X gantry with 8 wheels I only replaced the X belt for 9mm GT2. The backlash measured on X matches the Y now. All dimensions are now within a 0.2mm tolerance.

I have the 2016 xcarve, so I just removed the existing pulleys and replaced them at the same time as the belt (mine were not pressed on)… none of the steps/mm settings changed by more than .05 but I would recommend calibrating steps/mm if you haven’t done so before.