Shapeoko upgrade (7) – New belts, pulleys and idlers

Ok, so now that I have the much more powerful 276 oz-in NEMA 23 motors driving my machine, I went on and replaced all the pulleys and idlers in order to have them accept 9mm GT3 belting. I do this now while I have access, rather than having to disassemble it all once more should I feel the torque is just too much for the standard 6mm GT2 belts.


All of the hardware was replaced when I did the motor replacements. All good and well, but I still had one problem: the Shapeoko belt clips were not wide enough. Obviously, I could easily mill new ones, if it weren’t for the fact I had no working belts. Textbook catch-22 right there. 🙂

I cut off one side of the old belt clips and kind of managed to use them anyway, although I wouldn’t recommend doing this to anyone. But they held up for my first fast cut, which obviously was making wider belt clips from a pcb blank. If you look closely, you’ll notice that they are asymmetric. This is intended so that the clips won’t interfere with the V-wheels when they reach the endplates. The overall footprint of my new belt clips is exactly the same as the stock ones.

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Success! Although not for long, because a day later I noticed this:


It seems the combination of the GT3’s added thickness and the belt clip’s narrower walls are causing some problems. Although I must say, structurally they are still perfectly fine. But I think I’ll redo them soon and put a washer in between to account for the extra thickness.

Download the clips SVG here.




We’re a few hours of cutting in, and the inevitable happened…


And off course it happened in the last stretch of a 4-hour cut… But I guess there’s no one else to blame but me for not fixing this straight away.

I clamped the belt guerilla-style and quickly milled 1 new belt clip, which was also only temporary. I did mount it shimmed this time. 🙂


But to be really sure, I redid all of them out of aluminium. For some reason the 2mm sheet I had milled horribly, with the aluminium chips gumming up my endmill, destroying 1 Viper bit and leaving a bad quality end result. But it’s done and I need to move on. They will last a lifetime, even if they aren’t pretty…


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