I haven't been able to remove the screw, inserting a hex wrench into the hex socket I wasn't able to turn the screw in any direction. It maybe loctited. Threads visible are 1/2" Right hand probably NF though I didn't check actual pitch. Slight countersink in threaded hole opening I can see the threads continue below the surface. Maybe I can heat the item to 250° to try softening loctite if used.
I am thinking that it may have been for a shell end mill holder.
Clarkson and some others may shell endmills with a threaded body and the Clarkson Dead Lock had some setscrews that tightened the center screw .
You can see an example here .
I have one for an R8 shank but can't find it at the moment .
It would have at least 1/2" pilot thread .
I have some other smaller similar European threaded shell end mills that someone made an adapter for that I took a picture of .
I think these were more common in the U.K. and Europe so there may be some standards that I'm not aware of .
I know of a few shops where they were used at one time but likely not seeing much use now.
Spaeth, I have a Moore Jig Borer, what does a wheel dresser do on a Jig Borer? I am interested in any Metric tool holders with Moore taper.
Jim not sure shell mills are used in Jig Borer, I do some very light milling on one of my #3 Moore but with very small mills
Shot in the dark, your post said; "Always looking for Moore tooling I don't have." Did not specify Jig Borer tooling. The pantograph adds a whole new realm any brand of surface grinder. And like all Moore Tools they are top of the line.
My fault, I should have mentioned Jig Borer tooling. I do have a B&S surface grinder but rarely dress a radius, have a simple radius dresser that I use once in a blue moon. Your correct in that Moore tools are top of the line! Unfortunately using a pantograph to dress a wheel is beyond my pay grade.