I have an M1-A that looks just like yours AND I also have what I believe is a forerunner or precursor to the M1-A. I believe it’s a Carter R5-A. It has a collet that looks like a Stanley M2-A. But it is the same diameter as my M1-A, just taller. It is about 1/2” taller AND, in addition, also has an extra 1/2” of threading on the housing so it can adjust a full 1” deeper in the base. It does not have the Stanley metal plate on it and you can tell one was not removed. There was never one on it.I'm looking for parts for my old reliable stanley M1 A (i think that's the model number) specifically, the top.