What's This?

[Walt Ebie]

Couldn't find a tool forum so here's my question: ...tell me what this is for. I found it all rusted up in an old toolbox that belonged to my Dad and after I de-rusted it...here it is. The bottom is made for a half-inch socket wrench so it may be an attachment of some sort. The top part pivots on a cotter pin, about 45 degrees to each side and the little slide arms are fully extended in the photo. about 1 1/2 inches full wide and using the set screw can close down to about 3/4 inch. So i assume it's an attachment but the question is.....what do do with it? Scribe a circle or what?

 

[Bruce Lancaster]

I think it is to spin valves for lapping...many olde cars (not the Model A) had two shallow holes in the face used in valve lapping with a variety of tools. This one would likely use a speeder handle as the driver.

 

[1930artdeco]

Try the garage journal and go down to vintage tools.

Mike

 

[Anteek29]

YEP...good catch. Many years ago I made a Briggs and Stratton valve lapping tool using a wooden block with 2 appropriately spaced nails to engage the holes of the valve.
Inverted wood screw up the center...used a 1/4" drill to spin.

 

[Tom Wesenberg]

I haven't seen one like that before, but I agree with Bruce that it's for lapping valves.