That's more of a Boxford style of 4-way tool-post, where the top-slide has a large tee-slot. The projection on the circular part fits into the top of this slot to maintain alignment. The Myford doesn't have that feature AFAIK.

I don't think that it's actually off a Boxford though., doesn't look quite right.

BTW, it's ML7.

Edited By Clive Brown 1 on 27/08/2020 21:09:20

+1 that's not a Myford tool post but it could be adapted to fit. You might be able to take the dovetail part off the bottom, remove the threaded stud and handle and then drop the toolpost down over the existing threaded stud that sticks up from your topslide. You might have to turn up some kind of adaptor sleeve if things are not the exact size. The original Myford 4-way toolpost had a ratchet locating mechanism in the bottom of it but it is not necessary. The clamping force of the nut or handle on top will hold it firm.