Posted 6 years ago
stevieray1…
(1 item)
Has a tri-beveled point on end that causes the dial to rotate. Dial has a marked point as well as a pointer in center that appears to be adjustable. Has dial increments of 10's adding up to 100. Appears to be constructed of brass and some form of steel. I can not find any markings on the body except for the aforementioned dial markings
Possibly a depth gauge
This is an old version of an instrument to measure the speed of a shaft. When the shaft is up to speed you put the point on the end and keep track of how many revolutions are made in a minute. If the tachometer measures 540 revolutions in one minute then the shaft rpm is 540.
srarman is correct. Search ebay (etc) for "machinist's RPM gauge" (or similar terms) and you'll find other examples like it. There are also several shown here on CW in other members' collections -- I know I have one of these things myself too somewhere, but don't remember offhand if I've ever shown it...??