3-point Internal Micrometers

[Micke S]

The tool addiction can strike at any time without warning. This time I bought a couple of 3-point micrometers. The well recognized Swedish metrology company CEJ Johansson (now integrated in http://www.hexagonmetrology.se/eng/index.htm ) recently sold a lot of equipment on an Internet auction. I was lucky to get some of it for a reasonable sum.

I immediately measured a cylinder bore, which shall be 48.00 mm. The measurement shows that both the bore and the instrument are within good tolerances, unless both of them have the same error.

 

[Tony Wells]

Trimikes are very handy indeed for finding out of round conditions in work that has been done in a 3 jaw chuck. They are a little hard to calibrate, really needing set rings for it, but if you can bore a pretty round ring and get a good reading on it with another method, that should suffice for "non-official" work.

I'm a little envious. Those are pretty valuable.