On 2013-05-20, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Ok, 'solutions guys'...

I have some 0.010" phosphor bronze (spring temper) in rolls 6" wide x
80" long.

I need to cleanly slit some 3/8" strips x 80" from this without any edge
distortion.

We tried taking one a sheet metal house that had a long scissor-type
shear, and it cut it, but also curled the edge too much for our
application. It has to wind flat in a coil when finished.

The guillotine type shear? If it has newly sharpened blades,
and they are adjusted to just barely rub against each other, you will
get a much cleaner cut.

But the sheet metal house will not normally have the blades
adjusted that close, because that setting is wrong for the thickness of
metal they normally cut.

I've tried sheet metal hand shears without much joy, a nibbler just chews
it, and sawing it on anything we've got is impossible.

Understood.

We must not heat it. Also cost is an issue, or I'd have it done at a
waterjet and laser house down the road, but they want a couple-hundred
just to set up a job. For only five strips, that's not in budget.

A virgin roll has perfect edges, and rolls tightly. The mill that makes
the rolls from larger sheet stock cannot go narrower than 1".

Any ideas?

Yep -- at least a couple.

1) The way the supplier probably does it is a set of rollers with

sharp hardened edges on two axles, with smaller diameter spacers
between them, run interleaved. Gear them so they counter-rotate
and adjust them to overlap by say about 1/8" for what you are
cutting) and you can likely feed it in smoothly and get really
nice edges. This is even the sort of thing which makers of
recording tape used to use to cut a wide web of tape material
(several inches or perhaps even feet) into 1/4", 1/2", 1", and
even 2" wide tape for various recorders. If it'll work for that
for miles of tape, it should work for your 80" long strips.

2) How much heat is too much? Try cutting it a bit over-wide,
roll it up and cast it in one of the really low melting point
alloys (melt in boiling water) from Cerro, and then grind the
edges on one side, flip it over and grind the other side to the
proper dimensions. You might even be able to slide the puck of
casting around on some fine sandpaper if you can accept a likely
bit of width variation as you go around the roll.

Good Luck,
DoN.

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