Galileo's lathes

Well, in HIS time, I suspect it was probably little more than a shaft with a large flywheel turned by an apprentice. The end of the shaft would have a flat, coated with pitch. The raw chunk of glass is adhered to the pitch, and, then formed with the same techniques used for grinding a mirror. It might have been a vertical shaft instead of horizontal, though. Although I don't have them at hand right now, the classic reference collection "Amateur Telescope Making", edited by Ingalls, has a lengthy section on making a lens using a lathe. As with any power tool, it requires a skilled touch, because it is very easy to create disaster from beauty in only a heartbeat or two. As for what lathe to use these days? Pretty much any of them should do a good job, however, I suspect that one that uses bronze, cone-type bearings will be less likely to have the micro-vibrations that a ball/roller bearing type shaft may have. However, even a $70 Harbor Freight job should do an adequate job for experimenting. Regards Dave Mundt

Greetings and Salutations again... And if I had not hit 'send' too quickly, I could have included this URL:

And if you can find it, "Standard Handbook for Telescope Making" is a marvelous introduction to the whole subject of mirror and lens grinding, besides being very entertaining to read and illustrated with lots of photos.

- Steve R St Louis

I don't know.

But I was in Florence earlier in the year, and the Museum of the History of Science has a very impressive collection of Galileo's artefacts - including this one !

-- Die Gotterspammerung - Junkmail of the Gods