[imoverclocked]

Question for anyone who has used one of these analog measuring devices: the indicator seems to go all the way around before the camera zooms in to read the indicated value. Is this video actually showing the accuracy it is claiming?

[lazide]

I haven’t watched the whole video, but I’m assuming what they were showing was ‘move x from 0.00 to 10.00’ with the gauge showing the final move was to (actual) 10.05.

Which with how floppy that rig is, is pretty impressive.

Notably though, those gauges do need to be ‘preloaded’ (compressed into their ‘positive’ range) to be able to measure negative direction shifts, and while it looks like that was done, I can’t be 100% sure without analyzing it far more than I want to do right now.

Also, those gauges provide a degree of preload (not much, but some), which might be taking a bunch of slop out of the system and giving overly rosy accuracy numbers.

[toxik]

I think it’s okay that they use the contract force to remove backlash since they are actually controlling it. In fact, if you could do that well, that’s huge!

[lazide]

I don't think they could do that sustainably while it's actually doing 'the job' though, correct? It's pretty in the way.

[tgsovlerkhgsel]

Yes. The sphere at the tip has a certain radius, and the indicator will show zero (again) when the sphere has been deflected by its radius (i.e. the contact point is exactly at the center line). When out of contact, it's essentially telling you that you're missing at least a whole millimeter to the point where you should be.

Often there is a second needle indicating which of these situations you're in, but I assume it's not considered necessary because if you're 1mm off, the situation is (in the contexts in which these devices are used) very obvious.