I have an old capstan lathe waiting for a resurrection, but now I have one another lathe I use pretty much. These two lathes are quite different size, but I want to have some common tooling between them. I was playing with the numbers figured that I could mount the bigger one in the smaller lathe, if give up the top slide. Since this flipping threading too seems to work, I can live with it.
So I ordered a QCTP with some spares that was perfect for the big lathe.
Had to fudge measurements and finally I came up with a plan that has a spacer on the smaller lathe, that is turned to thickness to make it possible to change tool holder between lathes without too much adjustment.
Another criteria was that it had to be easy to remove to use original tool post with the topslide.
Anyway 80 mm by 110 mm by 25 mm hot rolled steel section was surfaced and markked.
Then I pinned it and clamped to the milling machine to drill the pilot for counterbore, drill 6,8 mm hole for M8 thread (this goes to cast iron cross slide) and finaly a couterbore for M8 cap screws.
Notice my crap-o-Z-set.
Notice my ATC

Pekka