Do any fellow Orchidians know where I may find one, or are there
any other ideas to make one?
First, If you actually contact Raytech by phone, or one of their
distributors, I'd bet they can send you one. Just because they don't
list it doesn't mean they don't have them. Catalogs tend to list the
most often needed parts.
If that doesn't work, remembering that laps usually have a standard
1/2 inch diameter center hole, the center threaded rod will at least
be the same diameter with most makes of faceting machines. That
suggests the nut is likely to be a standard part that, even if
designed differently from one machine to another, would still fit the
same threads, since threads are likely standard sizes. Measure the
thread, if you can, and then it would be easy to just get a standard
nut from any machine tool supply, or maybe even home depot, unless
it's a reverse direction thread or something. (depends on which
direction the spindle turns) Even then, it can be ordered. If you
want some sort of cushioned knob on it, that would be easy to
improvise. Just glue something to the nut...
Or, just take the thing to any decent machine shop, as a last
resort, and have someone cut you a nut if this really isn't available.
Anyone with a decent machine lathe could make any sort of threaded
nut you wanted, perhaps with a larger outside diameter with a nice
knurled finish too...