Comparing Gage Block Sets

I thought my offshore set was rated in microinches, but that wasn't the case. It was rated in hundredthousandths not millionths.

I think the economy sets are shown in tenthousandths not hundredthousandths, and your measurements seemed to bear that out. All of mine measured within the tolerances stated in my test report, in hundrethousandths of an inch, as best as we could measure using a third of the marked indications on a half tenth indicator, comparing to a AA grade Mitutoyo gauge block set on a Mit AA grade surface plat in a climate controlled metrology room.

For a hobbyist, and 170 kanuckistan pesos [ > 15 years ago], It will do me just fine. My worst block is just under a half a tenth out. I'm very happy with my set. If i work to half tenth tolerance one day I'll crow about it here!

EDIT: The surprising thing here isn't that they are very good (which they are), but that they actually tested them at all!
 
Dabbler said:
I thought my offshore set was rated in microinches, but that wasn't the case. It was rated in hundredthousandths not millionths.

I think the economy sets are shown in tenthousandths not hundredthousandths, and your measurements seemed to bear that out. All of mine measured within the tolerances stated in my test report, in hundrethousandths of an inch, as best as we could measure using a third of the marked indications on a half tenth indicator, comparing to a AA grade Mitutoyo gauge block set on a Mit AA grade surface plat in a climate controlled metrology room.

For a hobbyist, and 170 kanuckistan pesos [ > 15 years ago], It will do me just fine. My worst block is just under a half a tenth out. I'm very happy with my set. If i work to half tenth tolerance one day I'll crow about it here!

EDIT: The surprising thing here isn't that they are very good (which they are), but that they actually tested them at all!
Click to expand...

The Shars sets are good enough for what I do: 100% hobby stuff & NO customers (paid or otherwise) so that I can just follow my curiosity.

I would like to see somebody send a Shars gage block set to be calibrated, and then post the results.
 
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I just got a 81 piece HFS set, less than $100. It includes the calibration chart, each block has a serial number and the nominal deviation in microinches. As I read it, the ASME spec says the lowest grade is “Toolroom”, plus or minus 50 millionths, and all blocks in the set are below that, the worst being +32.

One picky point is that 70% of the blocks are + tolerances. Biased that way for wear? Or just luck of the draw?

It would seem that a cheap set with a table of deviations from nominal in microinches would allow knowing the height of a stack to a few microinches, even if it was not some preset number. Kinda fun, and impress your friends.
 
Why not just send one or 2 blocks out and have them checked? I looked at the prices awhile back and think it was like $6 each to have a block checked. Mics were less than $20 for small ones.
If you are trying to measure in microns and are fretting over a couple hundred bucks that is just silly.
Joe
 
One of these days I'll find an inspection stand for my Mahr 2 millionths indicator so I can calibrate blocks myself. If anyone sees one that is inexpensive, please PM me!
 
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