Here's what I know. It's made by Starrett. It counts revolutions of the shaft (actual number, not RPM). The shaft has a rubber cap on the end assumed to be for friction. The rotating dial counter is shown zeroed. It will count in either direction, 100 revs per 360 degrees. The thumb-forefinger handle on the left is stationary.
So what is its purpose? When would it be used, and how/why? I don't know.
__________________ Dan Horton RV-8 SS Barrett IO-390
I have one also, given to me by my father in law who ran a big lathe back in the days.
It?s a revolution counter, placed on the end of a rotating shaft for a specific time indicating RPM.
Was developed for machine shop use when machines were powered by line shafts.
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Don Pansier
Green Bay, WI (GRB)
RV-7 N450DP
W9LYX
It is a Speed indicator. It has several uses in machining. It can used to measure RPM when used with a watch, but mainly it is used for speed rates when cutting.
see: https://www.youtube.com/watch?v=SLWlkobzKgk
__________________
Restored and Flying '58 C-180A
Retired Vietnam Marine
2017 dues paid
If you look at an old engine shaft you will see a conical depression machined into its end. The rubber cone on this tool fit into the depression. The fellows are correct...RPM could be measured with a watch.
Thank you gentlemen. I like the cutting speed measurement with the wheel!
It came from the toolbox of an old friend and mentor who passed recently. I have other ways to measure RPM, so I think I'll retire it to an honored place on the shop wall.
__________________ Dan Horton RV-8 SS Barrett IO-390
Mystery Tool
paid
Linear Mode
