[TheForge] metal spinning

[terry l. ridder]

hello;

the other day i happened to be watching the
discover channel program 'how it's made?'.
this episode was concerning metal spinning
pots and pans. at best the information given
was just a terse overview. the episode did not
explain metal spinning itself. it is clear that
a great many things are happening all at once to
the metal.

the most basic example from the episode was taking
a large aluminum disc and making a large stock pot.
the form is a simple straight sided cylinder with
a flat bottom with a rim at the top. the aluminum
disc is placed on the bottom of the form and the
metal spinning lathe is spun up to speed. then using
a tool which reminded me of a huge roller skate wheel
the disc was pushed up against the form and into the
shape of a cylinder. to try and understand what all
was happening here, i took some plasticine clay and
made a disc an 1/8 of an inch thick. i then placed
the disc over a small metal measuring cup. it was clear
that the disc would have folds and creases if i were
to attempt to make a clay pot in this manner.

so what is happening with the metal spinning tool and
the disc? is the disc being drawn out using the tool?
the episode stated several times that the discs were
pure aluminum. they did state that the pots and pans
had to be heat treated during the process because they
were become hardened by the process.

one thing that was not mentioned in the episode is how
fast the metal spinning lathe is spinning the metal disc
that is to be fashioned into a pot or pan. would anyone
have a rough idea what the rotational speed of the metal
spinning lathe would be?

are there any good books available that gives a reasonable
working knowledge of metal spinning? does lindsay books 
have any books on metal spinning that someone would recommend?

-- 
terry l. ridder ><>