9mm belt upgrade

So having decided to upgrade all my steppers to the 269oz steppers for my original 2015 x-carve (so much easier since the 2015 model had barrier strips for motor connections so no rewiring needed), I’ve done a whole slew of upgrades. The first was upgrading the main x-axis extrusion for stiffness (the original with the 1/4-20 bolt stiffener just couldn’t cut it. Particularly when I added the CNC4NEWBIES ball-screw z-axis. The weight of that was twisting the spindle out of true. So after doing all that I realized that the 6mm original belts weren’t going to serve the 269oz steppers properly (they work, but seriously why get massive steppers and then use tiny belts, it’s like sticking a supercharged-Big Block into your Camry it would probably get you to the supermarket, but if you step down the frame is going to twist like a pretzel) so I was looking around at various options for 9mm GT3 belts, and saw some recommendations for the TBDCNC upgrade pack. I really have can’t recommend it enough. It all arrived in one box, ready to go with complete replacement hardware (thank god, since one of the idler wheels had stripped out the bolt when I installed it 5 years ago apparently so had to get that out with a screw extractor). I had the problem that my original steppers had the pressed on pulleys, so I needed new ones of those, and handily they come in the box. You get your choice of set screws, either regular bolts or the headless grub screws we are used to. A little blue thread locker and those popped right onto the shaft. The parts look factory original and made the process super easy. No “oh will this vendor’s item match that vendors?” and the belting is “real” gates belt! If you are considering the upgrade (i’d recommend this set). I love that this is a family business here on the east coast (clearly a passion project if you read their about page - plus any business with dogs that cute is going to be awesome! I know that Della checked over my order so no parts were missing!]):

Since the CNC4NEWBIES motors have hardwired leads (about 18" long?) unlike the connector version on the Inventables steppers, I just cut them to about 5" (like the original 2015 motors had) and armored them with nylon-mesh sleeving with heat-string tubing at the ends, just so the inevitable getting caught on something doesn’t nick the wires, crimped on some lugs and attached them to the barrier strip. 2-minute’s work. The machine looks identical (since I had the NEMA-23s on my machine anyway). Now I do have to be more careful, since in the past when there was a collision I could sort of count on the steppers stalling out instead of crushing the thing I accidentally left on the wasteboard, but not anymore! Now still not as backlash proof as a ballscrew, but way cheaper as an upgrade. I am sure I will eventually get up to a full ball screw for X and Y, but I need to do much more volume than I do currently to justify that.


That’s the kit I purchased, Also Luke sells the Nema motors that plug in, or at least he did when I purchased mine a year ago.

Since I have a 2015, that would not be a useful feature. But if you have a newer one with the connectors, that would be helpful. My older NEMA 23s had the leads attached and a barriers strip nearby. So the connectors would just be an extra in the way.

I will note CNC4NEWBIES only had 1 in stock when I upgraded. But the exact same item was on stepperonline:

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Hi. Did you find that the shaft length on the 269oz motor is shorter than the original motor, by about 3mm?
If so, what did you do to make this work with the alignment of the pulleys and belt?

Yes the shafts were a smidge short, so I kept them off the end of the shaft. The 2 set screws let you really bit on the shaft.

Thanks, so you mean that the toothed pulley actually sits past the end of the shaft?

Is there any sort of movement of the pulley because of this?

I feel them being quite rigid, but I’m more worried they aren’t square to the shaft…