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From: Robert Bastow <"teenut"@>
Newsgroups: rec.crafts.metalworking
Subject: Re: New carbide inserts look dull !! ??
Date: Fri, 23 Jun 2000 02:30:11 GMT

They may NOT be "ready to use"  Some brazed carbide tipped tools are sold, sans
relief or cutting rake etc..ready to be ground BEFORE use into whatever shape
the customer desires.

If indeed your cutters are "Ready to use" and if indeed, you have them set,
correctly on C/L, etc..they should cut, even if the cutting rakes, clearances
and angles are not perfect.

However, they probabably come with a perfectly "Sharp" point!  Not a "Good
Idea"..what you are trying to do is cut a fine thread..pitch equal to your feed
rate.  Result is bound to be "messy"

Might I suggest, that before use, you take your diamond hone (You DO have a ten
dollar diamond hone I take it??;^)...And hone a small radius on the
edge..anything from five to fifteen thou radius..depending on your feed rate,
finish requirements...and POWER available.

Try again, with a good cutting oil, and report back!

Then buy a "Green Grit" wheel..not a cheap one from ACE Hardware..but a good
quality one, about 80 grit with an "Open" structure and soft bond..ask at your
tool dealer..and try grinding your tools with a bit more top rake than generally
supplied..say about ten degrees. Finish hone with your diamond hone, don't
forget the radius!!

Experiment and ENJOY!!


Brian Evans wrote:

> Here is what I expect to be regarded as a really dumb question.  I've
> bought brazed carbide tool bits, tried them, and couldn't get them to
> either work well or to last at all.  I thought they were ready to use
> out of the box.  Do I need to sharpen them first, can I sharpen them
> after they chip, and what angles do I sharpen them to?
> I use them level to the work, set at center height so there is no
> relief.  They just seem to tear the metal, not cut, on mild steel,
> aluminium, 4140, which is what I mostly use.

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