Washers on VEXIQ spinning interfaces

When I started building EDR the rule was “always use a bearing block” for any moving metal to metal contact. At some point I also started throwing in a thin washer, somewhat to clean the spacing slop up, but also to help a little more with the friction.

Moving to IQ it’s all plastic so slip shouldn’t be an issue. But about 3 years ago VEX started putting washers in their design builds. I followed along with washers in my builds.

Now I’m going “wheel-washer-beam” or “gear-washer-beam” and even “Wheel-washer-beam-washer-gear” as a muscle memory construction method.

I’m also doing “Wheel-washer-beam-washer-washer-gear-washer-washer-beam” to help pick up the length of the 1x standoffs when creating boxes for wheels / gears to ride in to eliminate the minor slop.

Are other VIQ builders also increasing your washer usage? Or am I just using extra washers for no reason?

(Yes, cantilevering the wheel is bad but I didn’t want to go into a fugue state of "stopper-washer-beam-washer-wheel-washer-beam-washer-washer-gear-washer-washer-beam-motor. – At some point all the washers triggers the Wash your hands song ( Wash Your Hands Song | Music for Kids | The Singing Walrus - YouTube).

I do see myself using more washers than when I started last year, I tend to put washers between rubber collars and beams, or anything that is stationary, it seems to sort of help, but that might be a placebo effect, I was thinking of doing a test soon to see how much of a difference it makes. I have transferred this to all of the kids in my club, so you’re definitely not the only one.


One of the things that was pointed out to me by the other mentor I work with (retired brilliant mechanical engineer) is that the washers are the same width as the difference in the height between the edge of a hole and the “flat” edge of the beam. So, using washers in the right spot ensures a complete even stackup when you’re building, in addition to some reasonable friction mitigation. Not using them increases the friction and resistance you get from gears and wheels, because they will rub more easily, unless you are building things in a system enough that you can use spacers.

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This is the same reason we teach our kids to use washers especially for drivetrains and gearboxes. The sharp teeth on gears can rub into the side of the beams if washers on each side are not used. Especially the large diameter gears. Now for linkage or arm type mechanisms, the kids may or may not use washers depending on the application and load requirements. For my kids’ endgame arm this season, they are not using washers since probably will not make a big difference in load requirements but quite frankly they are running out of washers. The competition set does not come with enough washers so they are using sparingly.



Same argument as the others - our rule is any spinning shaft has a washer between the spinning part and the fixed part (whether metal or plastic - eliminate the drag); and we also use washers to push gears out past the side plates so they don’t rub. When in doubt, add a washer - less friction; faster spin, and less wear.