I need to put about 1" of 3/8-24 thread onto a 3/8" aluminum rod. Since I don’t know how to machine thread on the Colchester, I was going to use a die and hand thread. I was thinking of using the chuck on the Colchester to hold my rod while I thread.
How much stock would you guess I’d need inside the chuck to hold the rod steady? Is there a better way to do this? TIA.
I would wrap the rod in a rag, and lock it into that big vice in the Machine Shop. This way, it should not mar the rod, and the piece will be in a convenient work position.
Don’t know if tapping is also a part of your project to match with the rod you’re threading.
Adam Savage has an excellent video on tapping - worth a watch.
There are many “better” ways. Unfortunately we don’t have many “better” ways. Geometric dies for lathes are awesome
You could use the 5c collet block in the colchester standard 3 jaw. That would certainly keep you from marring it. That would probably be the way I’d do it.
Interesting thought. I remember that @nicksilva sometimes wraps pieces in scraps of aluminum drink cans.
Do we have any collets with square and/or hex exterior?
I’m concerned about my wimpy ability to hand thread something that big. I’m especially concerned about getting the die on there squarely. That’s why I was thinking about using the lathe as a vise.
We have both hex and square collet blocks for the 5C
Ah. I suppose I could use the square collet block in the vise …
Where do we store them?
Last I saw them, they were in a wooden case in the Haas toolbox. I would not put it in the standard vise but wouldn’t hesitate to put in the Kurt vise, since they are machined surfaces.
Got it. If I go that way, I’ll also put it between pieces of soda can so as to not mar the collet block.
The collet block is hardened, it’s work to mar the surfaces.
I’ve used the Colchester with my stock in the drill tailstock, and the die in the jaws. Put it in neutral gear and hand spin the chuck. Was very stable for finer threads and little chance of me doing something stupid.
Unsure if that would work well on a deeper thread like a 3/8-24
Since I last did this I’ve since learned power tapping on the Bridgeport; I wonder if you could use the vertical attachment for the Kurt vise to hold a threading die and do something similar.
If I were doing a bunch of rods, then tooling up is worth the time, for a one-off I would just stick it in the vice. Taps and dies tend to center and square themselves, it just takes a little attention.
I think you will find that 3/8 isn’t that hard to cut in Aluminum, but you will need to “dull” the threads with some Emory clothe, they will come out sharp. When you get to 1 inch black pipe, you will definitely need some help–that is sweat equity.
If you have a round die, we have die holders that fit in the tail stock of the lathe. Put your work piece in the chuck with shims around it for protection. Turn the headstock to start the threading. In aluminum you can do this under power at the slowest lathe speed.