Whats the narrowest nylon spacer i can use between two moving parts without them rubbing?
Is this a riddle?
I’d say as thin as you can slice it.
You can buy plastic shim washers from McMaster as thin as 0.001" thick. Teflon(PTFE) shim washers as thin as 0.005". You really don’t need much between things unless the 2 parts are large and could deflect into each other, but that shouldn’t be a problem if you design right.
You can also buy adhesive backed slick tape that is very thin and made of PTFE, UHMW, or PEEK. No cheap, but it’s so easy to just slap some on to reduce friction in places.
This question needs context.
Soft plastic will not last long on a drive train axle which has the wheels (gearboxes are probably fine though). It also will not last on axles which bear a lot of axial/side loads. The plastic will wear eventually.
I only bring this up because this is the reason our first regional in 2011 should have been GREAT, except for this exact problem on the drive train. We replaced the spacers with aluminum and our 2nd regional was our best ever up to that point in our history. Since your team is only signed up for one regional, you’ll want to get this right ;).
How close could a HTD 15mm belt get to the edge of a mecanum wheel without the screws on the mecanum wheel tearing through the belt? Would 0.1" be getting too close?