Quote:
Originally Posted by Jared341
As a meta comment to all FRC suppliers this year I will say that one of my bigger frustrations has been with all things hex.
Finding straight, well-toleranced hex shaft that has an decent fit on runout- and wobble-free hex bearings/gears/sprockets has been a real pain. We had to mix and match hex products from VexPro, AndyMark, West Coast Products, and McMaster (and re-broach/clean up some pieces ourselves) to make assemblies that we could slide together while still being mostly runout/wobble free.
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Just to elaborate on Jared's Post really quickly.
From what we've found (along with many others), aluminum hex bar tends to run a few thousandths oversize, usually somewhere in the .501-.503 range - a quick sanding with an Emory cloth or similar usually fixes this problem so it's not that big of a deal. Interestingly enough, 2024 Hex bar from McM does not seem to have this issue though as it runs a consistent .499-.500 over it's entire 3' length or so with very little run out. (at least the handful of pieces we've gotten)
Hex broached parts on the other hand are a completely different ball game. From what we've seen, WCP's parts run the tightest hexes at .501-.503, VexPro's hexes run on the larger end at .505-.507, and AM's stuff seems to be right in between the two. For some stuff, the difference in the broaches isn't a big deal, but if you're chasing backlash, that extra 5 thou in a gear's bore can get really annoying....