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From: Robert Bastow <"teenut"@>
Newsgroups: rec.crafts.metalworking
Subject: Re: Cutting tools, wedge of parent metal forms in front of point
Date: Fri, 04 Feb 2000 04:17:36 GMT

Absolutely, under ideal cutting conditions the "Edge" of the tool doesn't do
much work....That's why it lasts longer!

Under adverse conditions, that "wedge" welds to the tool, cuts deeper until the
weld fails, breaks off..leaving a bit stuck to the job and repeats the cycle.

Correct lubricant and/or surface treatment helps to minimise this..But if you
bear in mind the affinity that similar metals have for each starts to
explain the difficulty one has with getting a good finish on dead soft mild
steel with a HS steel cutter.

teenut..who once spent almost a year, watching planer blades under laboratory
conditions..and finished up..Knowing that I know not!!

"James R. Johnson" wrote:
> A friend of mine told the story of watching an ultra highspeed movie of a
> cutting tool (actually a shaper, because they could see the tool) made at
> the University of Texas back in the 60s.  He said that a wedge of the parent
> metal (the metal being cut) formed just in front of the cutting tool and
> that this wedge actually did the cutting.  It would cut for a while, then be
> peeled off into the swarf, a new wedge would form and cut for a while, then
> it would peel off, a new wedge would form, etc.
> Does anyone have any knowlege pertaining to this phenomenon?  What causes
> it?  If it happens all the time, why can't we cut anything with carbon
> tools?  Any comments?
> James R. Johnson     Shadetree Engineering         In the heart of Texas

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