I cannot remember why I bought these, they are a #9, #10 and #11
They have 1/2 inch socket on one end and a round hole on the other.

 

Steve, could you post view of each end? Any identifying marks besides the warning that shows?

Maybe that will make it easy to recognize.

John

 

No manufacturer markings

 

a friend reminded me that these are tap holders so one can chase threads deep in the object

 

That's it, I have a set of 6 I think, somewhere, in there, maybe. They are definitely in that building over yonder.
Used them once cleaning up the threads on the Spit6 frame.

 

Tap holders? How do they hold a tap?

 

The ones I have are different sizes for the tap shaft. Lots of places a extension can get too a handle with a turning rod just will not get in there.
I glad of it at the time.
If you look at the end of a tap holder, they generally have a place for a 3/8 or 1/2 inch socket (extension), If you have never did a frame up, you can not appreciate how nice it is to screw bolts into refurbished threads on a 60 year old car.