On Sat, 31 Jan 2009 00:43:58 -0500, "Ed Huntress"
wrote:


The lubricating qualities of your cutting fluid are very important when
you're machining in a non-commercial setting and your machine is low-powered
and/or flexible, and if you're using HSS or you're trying to extend the life
of your carbides.

Few of
us hobbyists are pushing our tools that hard, because we value tool life
more than flat-out production rates.

And the key thing for
most of us is that we'll do better with straight oil for most cutting of
steel than we will with coolant applied from a bottle, a drip, or a brush.

I think the key misunderstanding many beginning hobbyists have is the
reasons *why* coolant is used in commercial machining. It isn't for reasons
that apply to most hobby machining. For most of us, oil is better. And there
is no reason, for most of us, to go to the trouble to apply flood coolant
just to cool the cutting tool. The simpler answer is to slow down a bit so
you don't need to cool.

There. g

Ed. How about expanding on that. Tool Life is the main consideration
for me when milling. On the lathe, I just sharpen the HSS tool -
without dipping.

To find the RPMs for milling cutters (or lathe work) I've been using
the rule of thumb
RPM=Cutting speed x 4 / diameter of cutter.

In general, I use a cutting speed of 60-80 fpm for mild steel although
I recall the books say 80-100 for mild steel.
What speeds do you recommend to prolong HSS milling cutters for steel
/ stainless/ aluminum/ brass
Any rules of thumb that you use?

How about chip load per tooth?
Feed it till it squeals or vibrates ;-) ? [sounds like what T Nut
implied in a post from long ago]

Which oil are you using and how do you apply it to a milling cutter?
How do you keep it from going everywhere?

How are you clearing chips from a slot if you're not spraying the oil
with compressed air? Chips jammed in a slot shortens cutter life too.

Although I recently purchased a spray misting device for my mill, for
the past 20 years I've just been machining dry and living with
whatever end mill life I got. Always looking for ways to improve
things.

RWL