[SEL] OT lathe tooling for copper facing.

[Dave Otto]

Curt

I have never had much luck with negative rake lathe tools; They may be fine
in a CNC with a lot of power and coolant. To me happy they need to be taking
very heavy cuts and if you try to sneak up and take a light cut they will
want to skid along the surface. 

For a light duty machine; I would stay with positive rake tooling for which
ever insert type you chose. 
On a negative rake insert the rake is built into the tool holder. That way
you get six cutting edges as opposed to 3 on a triangle positive insert. 

Dave


> -----Original Message-----
> From: sel-bounces at lists.stationary-engine.com [mailto:sel-
> bounces at lists.stationary-engine.com] On Behalf Of Curt
> Sent: Friday, January 12, 2007 11:38 AM
> To: The SEL email discussion list
> Subject: Re: [SEL] OT lathe tooling for copper facing.
> 
> Yeah Rob, in a production environment where you are preparing 100's of
> samples for analytical testing, carbide is the most economical solution.
> Besides the fellow running the lathe is a metallurgical test machine
> operator not a machinist. He really has no interest in such details and
> he simply doesn't have the time.
> The old broken holder he gave me was surprising when I looked at it, as
> the triangular insert is actually held at a slight angle downhill. The
> p/n on the tool also indicates a negative rake. Truthfully I alway
> thought the tools were made straight and you made the rake positive or
> negative by either coming in above or below centerline. But maybe this
> is all part of indexable tooling, so that you never have to adjust the
> tool holder up or down. Just drop it in and go.
> Agree with the oil comment. In fact we've found kerosene work well.
> Curt
> 
> Rob Skinner wrote:
> 
> >
> > Hi Curt,
> > Are you dead set on carbide?  I'd use a high speed tool, give just a
> > little less rake than negative, generously round the point, hand hone
> > the tool so it's razor sharp, and use a lot of cutting oil.
> >
> 
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