On the subject, sort of....

I quit using RapidTap and such, for drilling or anyplace it would
"smoke", as it gave me a bad cough and a sore throat every time. Lotta
that stuff isn't as good for your health as it is for your sanity
(ease of work..no broken taps), etc.

On the subject of heat and carbide, it was pretty amazing at IMTS2008
to see Valenite (I think) and Hurco (I think) running a rough milling
technique called "Ram Cycle Milling" (I think).
Anyway, all my "I thinks" aside, on a 50 taper spindle they used about
a 3" diameter roughing mill by 2" depth of cut and literaly rammed it
into the work doing an edge cut (followed later in the demo by a
pocket cut), and would cut at high force and reasonable feed for only
about 1 or 2 seconds, back off for 1 second, and repeat. Scary to
watch, but nothing but the chips seemed to get hot.

Take care.

Brian Lawson,
Bothwell, Ontario.
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On Fri, 30 Jan 2009 09:40:47 -0500, "Ed Huntress"
wrote:


"Ecnerwal" wrote in message
...
In article ,
"Ed Huntress" wrote:

One thing that we hobbyists often forget is that machine tools used in
production today are mostly fully enclosed.

Of course, with a fully enclosed (and CNC) tool, might as well use flood
coolant rather than a mist...

Not necessarily. Most of today's advanced cutters, with multiple coatings of
ceramic materials (titanium nitride, titanium carbide, titanium
carbo-nitride, aluminum oxide, etc., etc.) can't tolerate thermal shock. So
they're often run dry, at speeds that produce red-hot chips. Or, if
necessary, some can be run with mist coolant. The coatings with aluminum
oxide won't work properly unless the AlOx is hot enough to vaporize, so they
don't cool them at all.

But running flood coolant, particularly in milling operations, will crack
the coatings all to hell.


Still using a can of oil and a brush, given my unenclosed manual tools.
Might consider cooling with compressed air, if I get a better compressor.

You probably don't need cooling at all, unless you're running your tools at
maximum speeds. What you and I need is lubrication, not cooling.