Gauge block question

[nosaj750]

I've got this machine shop surplus place I frequent on a regular basis. I usually pick up end mills for a couple bucks, reamers, etc… yesterday I ran across this set of old japanese gauge blocks fir $10, figured why not buy em they could come in handy one day. I get them home put a set of calipers on them, manual and digital just to make sure I'm not losing my mind and had forgetten how to read the damn things. As you can see in the pic the difference in the blocks are very small .992, .993, 1.001 etc. The problem is they are all the same size according to both calipers. Even tried metric since its in japanese. Has anyone ever seen anything like this? I'm not a machinist by far but I did work in a machine shop in my younger days so I'm pretty familiar with a lot if things in the industry and always under the impression gauge blocks would be different sizes if marked for that size. Any ideas why these would all be the same size but marked different? Maybe thats why it was $10… .lol…

 

[javand]

I can't see much from the photo but if these blocks are set of 1mm blocks with thousands of a mm incremental differences, your calipers wont have the resolution to see that variation.

On the other hand, the condition from what I can see in the photos renders this accuracy of the original calibrated blocks meaningless, since maintaining that accuracy requires calibration, and meticulous care.


You'll find a use for them for $10 though. They make good shims for doing tapers on a sine plate.

 

[nosaj750]

That is definitely a possibility. They appear to be old but, don't know how old. I'm guessing the 60s maybe by the look of the box. Maybe I should try and get the japanese translated just to satisfy my curiosity.