What type of chuck?

The A type mount accepts bolts that fasten the chuck to the spindle. Cam lock (D type spindle) would have holes that accept the pins located on the back of your chuck. The pins have a radius cut in them, which is the locking surface. The spindle has sockets around the perimeter that engage the cams with the radius in each pin. I'm not sure they use that system on turret lathes. It's very common on late model engine lathes, however.

The A and D type are very similar, the major difference being the bolts as opposed to the studs. If your spindle has a short taper, plus four holes (or more) tapped around the face, it's an A. Cam lock of that size would likely have six holes, probably 3/4" diameter.

Harold

Here's a web page for "D" type spindles. The next page has L type. Didn't check but I bet bet they are all there. Pics dimensions etc.

answer my own post. I checked this site out a bit.

Start on page 2.