The ram wouldn't retract more than about halfway.

I took it all apart, looked for debris saw essentially none but cleaned
anyway, stoned the edges of the keyway, it still started to stick about
halfway.

I was sure I hadn't bent it or anything...

The chuck taper was still in the ram, good and tight; popped that out and
no stick.

Last drilling job was pushing a Forstner bit through plastic pipe to
make it a little bit bigger ID. I guess it got hot, the ram grew, the
taper went in more.