Re: cutting threads on lathe

Jon,

Yeah, it'll work, been there, done that.

But, don't forget his parts are 12" long. Does his mill have the
needed distance from table to spindle to stand that long a part on
end?

Speaking of milling threads....before I had a machine that would do
helical milling I setup a spread sheet to generate helical paths
made up of short line segments. What was a little special about my
calculations was I'd input the diameter, pitch and a guess at the
number of line segments in 360 degrees and it would generate the
code, plus give the max chord deviation from true circle. By trying
different line counts you could come up with an acceptable deviation
value. If it was a precision thread the deviation could be
correlated to the thread pitch limits to keep the thread "legal".

Here's a little thread milling trivia...when you buy carbide thread
milling inserts why do they have different inserts for internal
threads and for external threads when the pitch is the same for both?

Doug

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
>
>
> doug98105 wrote:
>
> >fine',
> >
> >If you only intend to use the lathe for threading the ends of
your
> >pipe then save yourself some time/money.
> >
> >Buy a small turret lathe or conventional lathe with bed turret
and
> >thread with a die head. It'll be as fast or faster than CNC.
> >
> >
> WAIT a MINUTE! He can do it with the existing equipment he
> has, which is a 3-axis CNC mill! I got a little single-row thread
> mill some time ago to do some odd internal threads. But, thread
> milling can be done on outside threads, too. With a little program
> to crank out the arcs, you can cut beautiful tapered threads in a
> few seconds. If you need a couple of seconds to wipe off the
> chips while it is doing the next one, it should be fine. With the
> CNC milling of the threads, there's no technique to getting the
> right depth each time. Also, with a suitable clamp to hold a bunch
> of parts, he can line up the parts, and the machine can run down
the
> row tapping them all in a few minutes.
>
> Jon