brown and sharpe wee small hole guage

[dethrow55]

hello all wondering if anyone has any info on this brown and sharp hole guage pat. jan.11,1898. has a 2 inch base and tiny depth rod ????

 

[tornitore45]

All I know is that is called a depth micrometer. It measure depth of anything the probe fits.

 

[rlukens]

That is a model 605 depth mic. The shaft was probably turned down to probe a specific small diameter hole

 

[Blogwitch]

As previously mentioned, this is a depth gauge, not just for holes, but for any depth you can get it in to measure, say the depth of a slot.

To calibrate, wind back the centre spindle until it is just inside the fixed head bar of the mic. Then place the head bar onto a flat surface and screw in the spindle until it just touches the flat surface, readjust the thimble without moving the spindle in or out until it shows zero, and there you have it, calibrated.

Hope this helps

John