whit3rd wrote:
Instead of doing a lot of cuts with a long rod, I'd start by making about-the-right-length
cylinders (maybe just with a hacksaw), and holding them in a collet
or (even better) soft jaws in a 3-jaw chuck. Finish one end square, so that
when you reverse it in the soft jaws, the soft jaws can act as the stop for a
second operation that makes the 3/8" nub and cuts to length.

I though about chopping the parts up first, but there's no way to grab
them. The 0.500" side of things will be less than 1/8" deep- not enough to
securely clamp in the chuck and turn the other end down with. If I leave
the rough end of the rod longer, I end up with about 50% scrap cut offs.

The result would be a batch of parts, going from a rod, to rough cylinders,
to one-end-flat cylinders, to one-end-flat/one-end-stepped finished
length parts.

If I had or got a 1/2" collet, what would be the maximum "overhang" ratio
for clamped to unclamped material?

How would you cut the stepped part, by hand if you had to?