Ferdinand,
The lower RPM should not hurt the Dremel type cutters. If you attempt to run them at
a higher RPM than they are
designed for you will dull and/or destroy them. You may also have problems with chip
evacuation due to the shallow
flutes of the Dremel cutters. Feeding them slowly and using compressed air or better
yet, coolant during use will
help that problem if it arises.
You should be able to find end mills from a local source and will work MUCH better
than the Dremel cutters. If you
don't have a local source, MSC, DoAll, Production Tool, or any other mail order place
will have some to fit your
needs.
Like the Dremel cutters, the end mills will also be destroyed if ran at too high an
RPM. Simple formula: (SFM /
DIA) *3.82 = RPM. In other words, the surface feet per minute suggested by the cutter
manufacturer (or Machinery's
Handbook) for a given material to be cut, divided by the cutter diameter, multiplied
by 3.82 equals the RPM. (ex.:
(60SFM / .375" end mill) multiplied by 3.82 = 611 RPM) The feed rate at which you work
is more of an acquired feel
than anything but there are formulas for that as well. There are a lot of factors that
effect the RPM and feedrates
that could fill multitudes of pages. A Machinery's Handbook is as useful a tool as any
other in your shop so if you
don't have one, get one, borrow one, buy one, whatever. You might check with some of
the tooling suppliers that you
deal with. Some of them have little pocket guides that have a lot of useful
information in them. Some of them are
free but the ones that are not are usually are only a few dollars.
Milling on a drill press is pretty "iffy". The head of the drill press in not meant
to have much side stress or
pressure on it as is common with milling. It's just the design of the equipment. Also,
if it's an inexpensive import
type drill press it will have quite a lot of spindle runout and will greatly effect
your surface finish, ridgidity,
and tool life. That is of course multiplied by the lack of ridgidity of the cross
slide table. The small end mills
(<3/16") might be prone to breakage due to the runout. That being said, yep, it'll
work in a pinch.
Above all, WORK SAFELY!
You're envious? I work with millions of dollars worth of equipment on a daily basis
and come home to the sister to
Kevin's "big honkin' hammer". Actually I have a few pieces of small equipment but
nothing impressive or unusual.
Later,
Trent
Ferdinand wrote:
> Having recently added
> an xyz axis and rotational table to my drill press - the drill press has a max. rpm
>of 3600.
> Are there any milling bits that are useable with drill presses at that low an rpm.?
