Galileo's lathes

According to Dava Sobel's book, Galileo's Daughter, Galileo used some
kind of lathe to make his lenses. What kind of lathe would that have
been and what is the modern equivalent?

Ignorantly,
Allan Adler


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Greetings and Salutations...

On 18 Sep 2003 09:44:30 -0400, Allan Adler
wrote:


According to Dava Sobel's book, Galileo's Daughter, Galileo used some
kind of lathe to make his lenses. What kind of lathe would that have
been and what is the modern equivalent?

Ignorantly,
Allan Adler


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:
http://bobmay.astronomy.net/johnpierce/part4.htm
which has some interesting discussions of that
sort of thing.
Regards
Dave Mundt

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

"Dave Mundt" wrote in message
.. .
Greetings and Salutations...

On 18 Sep 2003 09:44:30 -0400, Allan Adler
wrote:


According to Dava Sobel's book, Galileo's Daughter, Galileo used some
kind of lathe to make his lenses. What kind of lathe would that have
been and what is the modern equivalent?

Ignorantly,
Allan Adler


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

On 18 Sep 2003 09:44:30 -0400, Allan Adler
wrote:

According to Dava Sobel's book, Galileo's Daughter, Galileo used some
kind of lathe to make his lenses. What kind of lathe would that have
been and what is the modern equivalent?

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 !
http://galileo.imss.firenze.it/museo/4/eiv10.html

Probably a good place to start looking.

--
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