Quote:
Originally Posted by Maldridge422
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This. I believe we bought 3/16" IIRC, solid core, clear (which was mostly a favor to me because orange has connotations where I'm from.)
We also bought UHMW rods, originally 2" but we found
1.75" was closer to what we needed. One of our mentors has a lathe and has been working on cutting them into 3" pulleys with two grooves apiece. Once bored to the correct round size, I take them to work and broach them for 1/2" hex on the arbor press there. We're then sliding them onto 1/2" churro, as the finished pulleys are a little easier to get on and off compared to regular hex stock; we may switch for the final production robot.
(Full disclosure, I work at AndyMark that sells the 1/2" hex broach.)
(And before anyone goes "but where are the kids in all this?": We put them to work as much as possible, but this is a case where the necessary machines and tools aren't in the same town or even the same county as the school. The kids will be getting very good at polycord welding once the rollers are done!)