slitting spring bronze

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.

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.

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?

Thanks, Lloyd

Reply to
Lloyd E. Sponenburgh
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Surface grinder with thin abrasive cutoff wheel.

Reply to
Existential Angst

Can you roll it up on some sacrificial form (dowel?), secure it (hose clamps?) and then cut it with a slitting saw in a mill?

Reply to
Pete C.

"Pete C." fired this volley in news:519a5c14$0 $14320$ snipped-for-privacy@ngroups.net:

Yeah, perhaps. That was one thought that already came to mind, but I don't have any experience sawing that stuff (it's tougher than a cypress heart). It's also thin, so I'm not sure we aren't going to end up snagging and lifting layers, even if we cut in climb.

But that's one idea certainly on the table (so to speak).

Maybe the same idea coupled with the abrasive wheel in the prior suggestion???

Lloyd

Reply to
Lloyd E. Sponenburgh

I have used a thin abrasive cut-off wheel in a dremel for cutting shims. With light pressure the edge does not deform. Keep it wet to keep it cool. Cutting by hand does not leave a very straight edge, but maybe you can rig up a guide. Although 80" would take a long time and several wheels.

You could try gluing it to a sacrificial board and using a slitting saw in a mill.

Reply to
anorton

"anorton" fired this volley in news:Z4adnYGxuv_twgfMnZ2dnUVZ snipped-for-privacy@earthlink.com:

It's 80" long. I don't have a mill with X-travel that long. If I did that, I'd have to run it through some guides by hand, like ripping on a table saw.

That last is another suggestion that's been profered. Screw two waste sheets together clamping (and maybe also gluing) the work between... then rip it with a brand new carbide blade and slow feed. ??? Of course, you'd lose the 'clamping' behind the cut; but maybe that's not an issue.

The length, unrolled, is the bugger-bear for handling it flat.

LLoyd

Reply to
Lloyd E. Sponenburgh

If you can roll it up, you have a candidate for a reasonably-priced wire EDM job.

It should be neat, but be aware that there may be a wire-breakage problem from the intermittant conductivity. Maybe, maybe not. If the EDM operator knows his stuff, he should be able to do it without a problem.

Setup would be minimal.

Reply to
Ed Huntress

How about roll it onto a tube, put the tube in a lathe, and cut with a thin abrasive wheel in a tool post grinder. I have a little adapter that holds a dremel on the tool post.

Reply to
anorton

Perhaps a nice ultra thin diamond wheel cut under coolant?

Reply to
Pete C.

Can you run that through a pair of rollers to flatten it out? It could even start the curve for the coil you want to make.

Reply to
Michael A. Terrell

That makes me wonder if a wire saw would also work, assuming it was appropriately immobilized (would casting the roll in machinable wax or one of the low-temp fixturing alloys (eg, woods metal) be too hot? Would the fixturing alloys contaminate it? I don't know...just thinking about ways to take the flex out of it for a clean cut.)

I wonder if putting it inside a pipe or bored hole and letting its own spring tension do most of the clamping would be best - then you could cut off a section of pipe with a section of spring-bronze rolled up in it, and it would not be (quite) as prone to uncoiling as you cut. I still suspect that some additional immobilization (such as wax casting) would reduce Murphy's access to the process.

Reply to
Ecnerwal

"Pete C." fired this volley in news:519a6273$0$10817 $ snipped-for-privacy@ngroups.net:

Do you know how one would load up cutting a fairly gummy non-ferrous metal? (I don't).

Lloyd

Reply to
Lloyd E. Sponenburgh

Try scoring it with a razor knife or one of those hooked blades you use to score Plexiglas.

I have found that, once you have a score line, spring bronze tears pretty easy in the direction of the grain.

Paul K. Dickman

Reply to
Paul K. Dickman

"Michael A. Terrell" fired this volley in news:E-mdnVGqy7eL_gfMnZ2dnUVZ snipped-for-privacy@earthlink.com:

I guess I could find a roller. The sheared edge was also rough. We'd have to dress it after flattening.

And we do not want it pre-curved. The purpose here is to keep it under tension so that when it un-winds a little (about one turn on a 2.5" hub), it stays flat-wound and self-supporting.

It's for a grounding strap on a rotary table. The table can only rotate

355 degrees, but house rules don't allow "wiper" type ground bonds in this kind of environment. 'Has to be metal-to-metal and bonded with a bolt.

The length of 80" was selected (stock sizes, so you picks what they carries) because that allows the strip to unwind a minimal amount in diameter with an approximately 10" length change.

Lloyd

Reply to
Lloyd E. Sponenburgh

"Paul K. Dickman" fired this volley in news: snipped-for-privacy@news4.newsguy.com:

There's an idea we haven't tried. We thought of scoring it, but also thought the way to break the score would be by brake-bending... never thought of _tearing_ it. Hmmm...

Now I've got to figure out if the grain runs the long way on this material.

LLoyd

Reply to
Lloyd E. Sponenburgh

I was thinking that myself, but like shearing, it might curl -- but proly less so. .010 is pretty thin. Also, you could score it from both sides. Ditto the wheel on a SG.

Reply to
Existential Angst

I wouldn't think that a spring temper bronze cut under coolant would be gummy.

Reply to
Pete C.

"Pete C." fired this volley in news:519a6b3f$0$23282 $ snipped-for-privacy@ngroups.net:

Maybe not. I just don't have any experience cutting it. I cut oilite all the time, but that's not the same creature.

Lloyd

Reply to
Lloyd E. Sponenburgh

you can usually flex it enough between your fingers to start the tear then follow it down. You will probably have to coil it up and rub the cut edges on some 220 grit sandpaper. The edge will be dangerous.

I can pretty much guarantee that the grain runs the long way. It would take some serious rollers to squeeze an 80" wide sheet down to .010 spring hard.

The next guess would be to use a rotary shear. You can adjust the blades close enough that there is zero clearance, but feeding 80" would be a pain in the ass.

Paul K. Dickman

Reply to
Paul K. Dickman

Clamp it firmly between a couple lengths of rectangular flat bar, the bottom bar should be 6in wide, use whatever you have on hand for the top bar, which will be used mostly as a guide.

Then, make a "scrawker' out of a HSS or carbide lathe bit, or from a Stanley or Exacto knife or whatever...

--it should only take a few passes to score .010 brass deep enough to snap off easily

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Otherwise, wrapping it around something and clamping it, perhaps with a two or three "Ideal" type hose clamp and then parting off on a lathe may work well also...be sure and clamp both the main coil AND the coil that you're parting off, otherwise you'll be in for a big surprprise.

Reply to
PrecisionmachinisT

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