Megamozg (megabrain), whose video Andre displayed, has some other videos worth viewing, including various shapes that are like simpler versions of ornamental lathes, although cut deeper. Also, new to me, casting a gear by forming the mould in a lathe:
Casting a gear
Thanks, Michael, that's an impressive find. I have a 7 year old grandson who draws a lot, but may be ready to start making models, it's a shame that Lego Tecnic is so expensive.
Bill