I have a turret lathe that would be great for this job, you can have it for
free


"adam smith" wrote in message
m...
I want to purchase and learn to use a lathe, because I need to make
new parts for some old 1930's air horns (diaphone fog horns) that are
not otherwise available. One part I need to make is the piston, which
looks like this:

http://www.airraidsirens.com/diaphon..._front_640.jpg
http://www.airraidsirens.com/diaphon..._close_640.jpg

It's 4" in diameter at the wide end, and 2.83" diameter over the rest,
by about 5" long overall. This piece fits concentrically inside a
brass cylinder, and it reciprocates at 180Hz when in use. The original
1918 shop drawings for this device spec the precision of the diameter
of the piston as "4 inches, to gauge limits--machine all over
outside". Newer drawings have the diameter as 4.000, +0.000/-0.002

I know these are made by first casting an aluminum blank (with a core
for the hollow part), but what I do not know is what caliber of lathe
and tooling I will need to do the machine work. I am not a machinist,
but I'm going to learn with the intent of making these parts and other
pieces for various antique sirens and horns. Thus, I'm interested in
buying a lathe to learn on primarily, but I want to be sure to get one
the first time around that,when I'm skilled enough, can turn out these
parts with the specified accuracy.

I'm interested especially in which import lathes are up to the task,
and what size is required. Yes, I realize many of you are now groaning
at my use of the word "import", but please let me explain. My budget
is that of the home enthusiast and does not allow for purchasing new
made-in-the-USA equipment. I've been reading this group for many
years, and many times have I heard "get an old South Bend, Atlas or
Logan". That is undoubtedly great advice for an experienced machinist
setting up a home shop, but I'm just starting out and I do not feel
that I could safely shop for a used lathe and not end up with a
junker. I also want a tool that is ready to use and not a project unto
itself. With these criteria, is an old SB still a possibility?

Thanks,

Adam