Had this left over from part of the repair work on my mill. Will probably use it again for the same job in the distant future, but until then I thought I'd give a new lease of life as a floating tailstock die holder.
I happened to have some round steel bar that was just a shade larger in diameter than the ID of the "cup" so all it needed was a skim to bring it to a slide fit. I then drilled out the centre to 12mm and bored a seat for 1" dies.
Once that was done, I chanced a bit of milling on the lathe to cut a slot in the side of the die holder (I'm still somewhat underequipped in the work/tool holding department for my mill). As I had predicted, she struggled a little with that job as the metal appears to be case hardened to about 1/4" deep, but got there in the end.
I then measured, drilled and tapped an M5 hole for locking the dies in place with a grub screw and gave it a whirl.
I've been wanting one of these for ages and I'm quite pleased with the results, despite it being a little rough around the edges