I finally got the 5C collet holder out of the 5914 spindle. The
approach was a combination of using the aluminum spindle nose protector
to put pressure on the holder and a piece of 1" black iron pipe from the
back, hit with a big steel hammer.

What gives on the nose protector is the threads, I think. The first few
threads on mine are broken off, and have been that way for some time.

The holder was caught by a wooden dowel held in the tailstock chuck,
with a rag tied around the dowel, thus protecting the ways and the
holder.

Joe Gwinn