That's a darn sight more involved than the first part I made when I got my first lathe. Turning, grooving, boring, and
knurling! Impressive.
If an endmill is going to be attached to the spindle of a lathe, it really should be via a collet chuck.
Or maybe a one-off split-bushing held in a scroll chuck if someone new to the game doesn't have a collet chuck yet.
You should probably take care not to lose concentricity, though.
In a pinch, I think this should work if you didn't want to risk holding an end mill in the chuck jaws directly:
- Use a hacksaw or bandsaw to cut most of the way through the side of a piece of stock that's a slightly larger diameter than your end mill and about as long as your chuck jaws are deep. You want the slit deep enough that it will compress without too much effort in the chuck jaws.
- Fill the periphery of the slit with shim stock of some sort. Cut up pieces of an aluminum can, or even a popsicle stick would work.
- Tighten the chuck jaws on the stock until the shim stock is gripped tightly.
- Face and bore a hole the same diameter as your end mill all the way through the bushing you're making.
- Carefully loosen the chuck jaws until you can just remove the shim stock without moving the bushing in the jaws.
- Insert the end-mill in the bore and retighten the jaws.
I'd use aluminum or something soft for the bushing so it bends easily and won't require as deep of a slit. The process above avoids removing and reinserting the bushing from the chuck jaws.
In case
@mickri hasn't discovered this yet: in general, removing a part from the jaws of a scroll chuck pretty much guarantees you'll never get it re-held in exactly the same position (you'll lose both radial and axial alignment).
Since the flutes are ornamental, though, you could aways just use a half-round file to create them (I'm one of those weirdos that enjoys hand work).
For small radius flutes, you could also
broach the longitudinal flutes: hold a radius cutter on it's side in the tool post, manually move the carriage right-to-left, pulling up a chip, feed in a couple thou, repeat until you're at depth. In steel, it would be tough going with a large radius once you start making a larger chip.
There's almost always a way with a little ingenuity.
