Ebay micrometers, etc

[The Radius Kid]

Originally posted by tminer
Got the mics and dial bore today. Cheap cases and absolutely no instructions. But they seemed to be OK. They felt solid and smooth. Didn't seem to be much slop in the mechanism. I don't have any real experience with mics, but I'm approaching geezerhood, and been around a bit of precision stuff off and on over the years.

Am I correct that the .0001 reading is the one closest to ANY .001 grad?

Tom

Geno's right,good tools make all the difference.
With experience,you'll know when you've got a good tool in your hands[hopefully your own!].
Those .0001" readings can be read if you know how.
When you check the mic with a standard,be sure to use the same feel when measuring.
Also remember that a mic is not a C clamp.
Don't use it like it is.
I assume you know how to read to .001"?
Let's say you see a reading of .323" and a little bit.
To find what that little bit is,follow around the mic body with your eye until you find a number that lines up with a line on the spindle body.
Let's say you come around and see that it lines up at 6.
That means you have .323" + .0006" = .3236".
Simple,no?

 

[tminer]

Originally posted by The Radius Kid [B
Simple,no? [/B]

Assuming that the 6 in your example is the number on the mic body, not the spindle, yes.

I got to use them a bit Sunday. I only measured one cylinder bore and piston skirt, but repeated the measurements several times and my results were consistant.

I do consider this hobby level. I feel that the weak link is going to be me, I probably wouldn't benefit from the more expensive, name brand sets. I'm using these to check tolerances, not set them.

I wouldn't want my machinist to be using these, but they don't seem to be junk (unlike the set of T-bars that I got from Harbor) and hopefully they will have reasonable durability.

Thanks to all. I do appreciate the feedback. The info I've chosen against is as valuable, if not more, than the rest.

Tom