Poor man's bore gauge?

[James L. Martin]

Phil, I have 2 of those, although they are neat and I used them 30 years ago they are not that accurate. Better than nothing but they can't compare to my Stan Baker set that measures 10 to 410.

[Grouse28]

I have one of those also. One of several gauges I have.
They were made in Germany and marketed by Frank Mittermeier out the Bronx, NY. They appear in a few catalogs from the 50’s and 60’s.
Copy of the instruction is attached.