What’s this?

[ACHiPo]

I'm thinking homemade tap holder.

 

[4GSR]

I believe there was a rod mounted in the cross hole, and the thread held a set screw or thumb screw. The knurl was for grabbing the holder and rotating it in the spindle with some kind of indicating tool mounted on the rod. Probably used on a jig borer.

How about that?

 

[mcostello]

Taps seem to be not standard size shanks, try and see if any size fits.

 

[RJSakowski]

An arbor for an adjustable tramming tool? A thumb screw in the end threaded hole would lock the swing arm in. The knurl would facilitate rotating the spindle.

 

[jcp]

I think 4gsr and RJSakowski are on to something........both make sense along the clock shop tooling guesses.

 

[kd4gij]

It would not be accurate for a tramming devise

 

[chips&more]

I see tooling sometimes that is special made only because of medical issues. Like if the person has arthritis in the hand(s).

 

[kd4gij]

My best guess would be shop made live center for small wood lathe.