"Tom Gardner" wrote in message
m...
Take a look: http://www.metalworking.com/DropBox/wire_cutter.jpg

Tom,

Neat gadget. Have you already decided on the inserts, or are you open to
suggestions? You can buy inserts with holes for a securing screw. The screws
aren't cheap, but they're not crazy and that would be a quick way to index
them.

It would probably be a good idea to have the inserts nested in the block.
When we build our dies with steel punches and trim steels, we go to great
lengths to have solid steel/cast iron support (shoulders or keys) in every
steel in order to keep them from moving. Carbide would be significantly more
susceptable to failure due to a sloppy fit.

I would not have the carbide inserts sliding against each other, if you can
avoid it. This rubbing will cause premature failure, as well as excessive
stress on the arm and base block. While rubbing will give you the advantage
of nearly zero burr, your insert life will be shorter.

I'm not sure what an ideal clearance between your inserts would be.
Typically, 10% of material thickness is used in many punching operations,
but you may find that this much clearance will create a massive burr, deform
the end of your wire, and smear metal on your inserts (causing premature
failure and nasty cuts). Ideally, you could make some shims and try out
different clearances.

As your clearance increases, the required force should decrease, which
should increase the lifetime of the wear components within your tool
(bearings, inserts, wear surface on arm, cam, motor, etc.)

Finally, I would take care to make sure there is no slop in your tool at
all. Again, if things don't fit correctly this will cause premature failure
(which can be fun when it's burried inside some monster machine).

Just my $0.02 worth.

Regards,

Robin