On Feb 15, 11:08 pm, Tim Wescott wrote:
On Fri, 15 Feb 2008 10:08:56 -0800, Frank Warner wrote:
I'm a part-time knifemaker with a mini mill. Mostly I use it for
drilling & tapping but occasionally need to ruin, er, machine a piece
with its regular milling capabilities. This can involve end cutting or
side cutting.

Over the years I've collected a variety of end mills, mostly from sets,
all center cutting, 2-flute and 4-flute (I understand the difference),
single end and double end. Must have 2 or 3 dozen of these in different
sizes, all dull.

In fact, they seem to go dull incredibly fast, although they cut fine
when brand new. Might be my technique, might be the mini mill (not rigid
enough), might be I'm not holding my mouth right. Might also be because
they are the cheapest end mills available so they can be sold in sets
for $35 or so.

So I'm looking to buy some quality end mills -- just straight, center
cutting mills, in basic sizes 1/8" 3/16" 1/4" 3/8" 1/2" etc. And I want
them to last a little longer than the sets I've been buying.

I've got the MSC Big Book in front of me, and there's a bewildering
arrays of brands, styles, materials, coatings, functions, and I presume
quality. So I just don't know where to start in making a decision about
which one(s) to buy. My budget is not unlimited so I can't afford to
experiment with tooling that won't do the job.

I am cutting mostly annealed carbon steels, stainless, damascus,
titanium, German silver and lots of softer stuff for scales and
embellishments. Most of this is just light cuts to straighten out an
edge or make multiple identical pieces. Shallow slots. I've used the
mill to cut the flats on hunting knives, taking 0.005" off at a time.
Even some freehand stuff for inlays. The rest of it is probably as
varied as the stuff you guys do.

If any of you have any recommendations, I'd be grateful for them, and
any other advice about end mills you'd care to share.

-Frank

Thanks for asking this question -- after looking at the links Gunner gave
I now understand why I lose an end mill every time I try to cut steel.

Next time I'll try for more patience.

Does lubrication and/or coolant help?

--
Tim Wescott
Control systems and communications consultinghttp://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
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Coolant definitely improves machining results, and the cutting tools
will last longer. I use COOLTOOL II almost exclusively for milling
and turning by hand brushing or squirting, simply to keep the mess
manageable and peace at the home front as my work shop is in the
basement.

This stuff is good also for single point threading in the lathe. For
tapping I use some 40 year old CIMCOOL "strawberry jam" (still
available). Both are innocuous and do not smell or cause rust. I
paid about $50 for one gallon of COOLTOOL II 5 years ago; the CIMCOOL
I got for free way back when but when I priced it recently it was
listed for $175 per pint! It is good stuff. I use both lubricants
for everything, all steels, stainless, carbon and tool, aluminum,
titanium, brass, bronze including aluminum bronze, plus any mystery
metal I run across.

I am not saying that it is the be-all and end-all for production
machining, but for all around workshop use, and for some pretty
complex parts, it is satisfactory for my purposes. The CIMCOOL was
indeed used in production tapping of aluminum, cast iron, and steel.

Wolfgang