On Sun, 15 May 2005 02:36:38 -0700, "Harold and Susan Vordos"
wrote:


"Erik G" wrote in message
roups.com...
Hello,

The shop that I work at has special order carbide inserts, and due to
heavy feed to speed ratios on our machines, we have found it necessary
to hone the inserts. To keep them in tolerance (.002 hone) we have put
them in a tumbler with some stones and silicon carbide sludge... this
method because its worked for us on lighter hones. This time though,
the inserts are all chipping to hell! I tried putting even one piece
at a time to fix it in case they were bumping each other, no help.

Now I am getting the blame from my boss, and whether it is somehow my
fault or not, getting the blame is just unacceptable.

Any advice from those experienced in honing carbide??

Thanks,
Erik


I gather you have far too many to do them by hand? Breaking the edge of
carbide roughing inserts used to be the norm when I broke into the trade.
The recommendation was to hone a .005" 45 degree angle on the cutting edge,
which prolonged insert life considerably. For those that may not
understand, negative rake inserts do not touch at the tip when in use, but
cut back on the insert top, location depending on depth of cut and feed
rate. It's commonly referenced as the "false cutting edge".

I'd suggest a quick stroke with a diamond hone on each face and tip------I
think you could get them quite close with just a little effort.

Harold


Or pick up one of the small bench top "lapping" machines that are
collecting dust in many machine shops, holdovers from days when
inserts were quite expensive.

They use a diamond wheel in the shape of a donut, held in place by
magnets, so you may swap between grits quickly. They will spin at slow
rpms either fixe or in a reciprocating motion, with a quickly setable
table with angle gauges.

I love mine, as inserts are expensive for me. Mine is a Leonard
Grind-Lap, but the name has been changed a number of times over the
years, nearly all being made in Santa Ana, California.

They turn slow enough to also work marvelously well on HSS also.

Gunner

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