"James Waldby" wrote in message
...
Tom Gardner wrote:

Take a look: http://www.metalworking.com/DropBox/wire_cutter.jpg
This rough drawing shows a cutter to cut 3" pieces of flat steel
wire, 3 at a time, every 0.5 seconds. The wire is advanced
through the block between the two shown 3/4" x 3/4" x 1/4"
carbide inserts. [...]

You also wrote "The block is kinda' buried and the block is
bolted onto a flat apron from underneath" but if perchance
you have access to the back side adjacent to the white end
(of the upper-right block in diagram), maybe the following
would work: Instead of just a recess, cut all the way through;
braze the square carbide inserts on to a length of square key
stock. Use clamp bolts through the block top like on a lathe
tool holder. To change cutting edge, loosen bolts, slide
stock out the back, rotate 90, slide back in, tighten bolts.

Alternately, leave the recess as shown; cut the block
between the insert end and the bushing bore; bolt that
part to the apron from above rather than underneath; to
change the inserts, unbolt the block part, pull it out,
change the inserts, and bolt back in.

Re the moving arm, preload, and clearance -- if you
tilt the axle forward 1 degree and mount the guide
carbide at matching angle, you could have 0 clearance
when the moving carbide hits the wire, and a few
thousandths of clearance at end of cut. Or negative
clearance at start of cut, and 0 clearance at end.

You wrote somewhere that cutters "have to be but-tight
to each other or the hard steel wire forces them apart
and destroys the carbides and leaves a bad burr." Would
it decrease wear if the center of the carbide face were
relieved? Also, how much difference in cutter life and
burring does rake angle make?

-jiw

A burr causes problems after the cut. The wire then gets bent 180 deg.,
like a Bobby pin, then gets a 1/2" long 16 ga. staple and jammed into a hole
in a block of wood. 98 of these tufts make a grill cleaning brush. A burr
will cause the cut wire to drag a little on one side or the other and the
bend won't be in the center.