On Fri, 15 Jul 2005 12:52:32 -0400, Ned Simmons wrote:

In article ,
says...
On Thu, 14 Jul 2005 18:50:40 +0000, Tom Gardner wrote:


The part I need thoughts on are how to pre-load the carbides in such a way
that it is easy to unload to change the carbides...(notice I get 8 cutting
edges on each insert!)

Tom, this might be a crazy idea, but I wonder if it'd be too complicated
to incorporate a mechanism to rotate the cutter 90 degrees on each return
stroke, thereby presenting a "new" cutting edge to the work on each cutting
stroke. This would make the cutter last 4 times as long between changes,
requiring the cutter only to be flipped over when dulled. I'm imagining some
sort of a ratchet/indexing mechanism.



With the right details it's possible to do this passively.
The rotating tools need to have a circular form and the
force that drives the rotation is usually a result of
placing the cut point somewhat off center. I've built
cutters for tungsten wire (tungsten is horribly abrasive)
that operate up to 1800 pieces per minute with auto-
rotating tools.

Yes, that's much better for a number of reasons. When I was writing up
my description I was thinking what a waste it was to not be able to
use up all of the cutting edge on each face of the square cutter. With a
passively rotating circular cutter, much more of the total cutting surface
can be exploited. I would think that another advantage to an offset
circular cutter would be in its cutting action; more of a slicing
action than a chopping action (think of the angle on a guillotine
blade), potentially reducing burrs and reducing the power needed
to make the cut (and that saved power can be translated
into increased speed).