What’s this tool?

[D.sebens]

Dad asked me if I know what this is. I have no clue other than some sort of rotation gauge??

 

[Jim in Wisconsin]

I think it's a revolution counter. You hold it against the center of a revolving shaft and it counts the turns. You have to do the timing separately in order to get rpms.

 

[D.sebens]

I think it's a revolution counter. You hold it against the center of a revolving shaft and it counts the turns. You have to do the timing separately in order to get rpms.

Yes I believe you are right. I spit some random descriptive words into the googler and came to the same conclusion. Thanks for the fast response!

 

[Jim F]

Tachometer.......

 

[benmychree]

The bump on the dial is to count full revolutions with your finger while concentrating on watching your timepiece.

 

[RaisedByWolves]

Yes I believe you are right. I spit some random descriptive words into the googler and came to the same conclusion. Thanks for the fast response!

LOL!!!