[Brandon Holley]

Originally Posted by Nick Lawrence

Rather than spend hours machining spacers to 0.0005" tolerances, we felt our "quality" maching time could be better used for the parts that really needed it.

Personally, I'd rather spend the extra time and run #25 chain all around. The weight savings is huge.

In my 12 years, I've run #25 chain on 9 robots (1 other was #35, 2 others were belts) and never threw a chain. You definitely don't need 0.0005" tolerances to get the alignment right. What you do need is careful design, and a little love at final assembly to ensure everything fits as designed.

I understand the "bullet-proof persona" that comes along with #35 chain, but I think any team is capable of using #25 if they want to. It just comes down to taking the time and effort in areas where you usually may move fast. Theres no need to machine spacers of +/- 0.001" of each other when you can buy shim stock and punch out spacers in whatever size you may need.

I know our final assembly of our drives with chains was carefully done over a couple days to ensure everything fit as intended. This is at the point where all of the pieces of the drive are DONE: machined, polished, cleaned, anodized. It's often tempting to rush and throw every piece together in an hour. I think our track record shows taking your time at this step is time well spent.


One reason we actually switched to belts was to make assembly a bit faster, which absolutely did decrease the time required at that step.

-Brando