According to :
DoN. Nichols wrote:
[ ... ]
Hmm ... the 4" diameter will probably call for slower spindle
speeds that the Micro-Mark can provide -- and more torque. Especially
so because you insist that stainless is your material of choice. I
really suggest that you experiment with something like 12L14 steel, and
compare how easy that is to machine to what is needed with stainless.
I'd be a *lot* happier if you were not insisting on stainless.
And I'm not sure *why* you insist on stainless. If it is inside what
you are making, it can be lightly coated with oil, and you will have no
problems with rust. If it has to be out where people can handle it,
then you might want stainless.
Actually most of the parts in question will be enclosed most of the
time but the device will be opened up frequently for adjustments.(I
just don't know if S.S. 316L would be over-kill).
I think that it is serious over-kill -- and it might not be the
best material for other reasons, such as difficulty hardening it by heat
treating..
The Micro-Mark probably could make a 4" x 4" *square* pocket
fairly easily. Though you might have to make two or three passes with
Stainless to get 1/16" deep. To make a round one on a small machine,
you would be better off with a rotary table -- *if* the overall size of
the workpiece is small enough so the corners will clear the column as
it is being rotated.
For this particular operation the work will be 4-1/2" x 4-1/2".
Hmm ... and the round depression is centered? This could be
nicely done by a lathe. Let's see -- 4.5" square means that the
diagonal would be 6.36" diagonal, so a 7" lathe could handle it, if it
had a 4-jaw chuck which could extend the reversed jaws out far enough.
That diagonal applies to the distance from the cutter axis to
the column as well, when working with a rotary table.
[ ... ]
A lathe is a *lot* better as a mill than a drill press is. The
setup is awkward, and the travel is less than you would probably like,
[ ... ]
The lathe as a mill seems to bring with it a different set of problems.
One operation will require that I start with a 3/4" rod and *square*
one end down a 1/4".(1/2" x 1/2" x 1/2" x 1/2"). This would take some
kind of cutter that I'd have to slide the word under.
An end mill in the lathe's spindle (in an end-mill holder) and a
milling adaptor replacing the compound to allow vertical adjustment of
the workpiece. The square could be accomplished with just this, but
what would make it easier would be one of those collet sets which holds
5C collets in either a square (for four sides) or a hex (for six,
obviously), which could be held in the vise on the milling attachment
and be rotated one flat per pass to produce the desired square end.
(And that is just
one of several "square" parts involved in my first project). That is
why a mill-drill is my first choice at this time. It would seem easier
to use a mill as a lathe instead.
That latter depends on the mill. First off, you will need some
kind of workpiece holder (like a chuck) to fit the spindle (and a larger
spindle is better here), and a good way to hold a cutting tool.
Or -- you could mount the workpiece on a rotary table, and
*mill* the workpiece to shape as you rotate the table.
It would be a lot easier to explain the limitations of each
route if you already had experience in using the basic tools, and you're
trying to decide which tools to get, so you don't have that experience
yet.
Good Luck,
DoN.
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