I don't know if you're interested in this kind of thing Norman, but there is a Dave Gingery book on adding screw cutting capability to the gingery lathe, and I Imagine it could be fairly simply adapted to your lathe -- it's the Dividing Head and Other Accessories book -- a small paperback. Since the Gingery lathe starts out with only a faceplate, and you use it to build up to the screw cutting capability, I imagine you could do the same with only a 3 jaw.
You could make a graver with square teeth to cut threads in a 1/3/4" dia piece of tool or drill steel. Put flutes in your blank and have a tap out of it. Unhardened it will cut aluminum, or hardened, steel. While the threads may not be perfect, it's the register that counts. Also if you make a faceplate, you will true the face of the plate anyway after it is mounted. A 1" to 2" thick aluminum faceplate works fine, and with it you can make a steel one if desired.
This kind of thing may not appeal to you, and certainly a purchased set of workholders is faster and easier. But if you enjoy working things out like this, it can be interesting work going from nothing to something.
