Monarch 613 Tailstock quill won't fully retract

I have a Monarch 613 16x30. I was drilling out some stock yesterday, and when I went to retract the quill it would suddenly only return about halfway. No difference in high/low gear, and it always seems to stop at the same point with no give. It's worked perfectly up till now.

I figured I'd try pulling the quill out so I could look in there to see whats going on, but I can't seem to get it quite all the way out. When it's got what I expect is an inch or so to go, its hitting some sort of stop before it comes out of the tailstock housing. On the far side of the tailstock is a round disc with two screws and a threaded hole in the center, and what looks like a pin halfway between the two screws. Based on a 612 parts diagram I found with a seemingly identical tailstock, it looks like that's a key in the side of the quill, and is presumably also what stops it from coming out, but I've been unable to figure out how to remove it. A jack screw in the center doesn't budge it, and I cant spin it either.

Anyone know the proper way to pull the quill out, or some other way of fixing the apparent jam on retraction?

You should be able to screw the LH screw out the back after removing all the bits between the handle and the top casting. That'd let you see the back of the quill. I can't see how the key is attached with the parts manual but there could be some screws under the paint.

I was able to get that back panel off this evening, what I'd thought was one thick back piece was two painted together, with the second half held in place by the gearing; once I split them with a razor it popped right off. Unfortunately it only lets you see the high/low gear setup - the quill's threaded shaft goes through a solid piece (the second part of the back) that would require I disassemble the whole gear system to get it out.

May just be what I have to do, but before I go dealing with a bunch of little awkward to get to set screws and pins, anyone have suggestions for an easier way to remove or otherwise inspect the quill?

I've got it all sorted out and fixed now.

As far as removing that back gear section - remove the top high/low selector handle (3 socket head screws on top, and it lifts up, its keyed into the part it moves rather than affixed with pins), pull off the handwheel mechanism, and pull the pump handle out (4 socket heads) and the whole back segment, gears, and leadscrew pulls right out.

As to my issue, at some point in the past, apparently someone had forced the quill into that big key on the side hard or often enough that they broke off a chunk of the flange on the leadscrew nut (part Y115 in the parts diagram) that was supposed to act as a stop against that key, allowing it to overextend and come off the leadscrew. Obvious in retrospect, but once it came off since I was drilling, the quill twisted slightly, going out of alignment with that key, so I was hitting the key on retraction, which explains why it was such a solid stop every time.

Could have been fixed (had I realized that was the cause) by twisting the quill just a hair, but just as well I took it apart, as I had that chunk of flange sitting behind the quill plus some random bits of metal flakes that could have scored and chewed up the bore in the future.