Shim Stock

I wouldn't know the best way, but I can tell you how I cut some when I was replacing a reed valve on a little compressor. I sandwiched the stainless between two thin pieces of sheet steel (I think it was pieces of an old paint-thinner can), holding the sandwich tightly and close to the cut in a vise, and cut through the sandwich with a cutoff wheel in a Dremel.

It cut clean, but it was tricky to keep shifting the sandwich in the vise.

I have cut reed valves for Cox 049 engines out of sheet brass with tin snips, and rubbed the edges flat again with a burnisher (well, the handle of an X-Acto knife, but I said "thou art a burnisher" before I did it).

A piece of 0.020" stainless I salvaged from an outdoor sign cuts satisfactorily with tin snips.

jsw

Well, tinsnips are OK, a full bench shear is better, and if the edges matter I've used etching after putting a pattern on in Kodak photoresist (the spraycan type, UV exposed...) like printed circuit fabrication uses.

Fastest material removal was with some mild nitric acid solution, but that's a bad idea if you don't have a fume hood, because there are some brown gasses involved.

Guillotine paper cutter.

It might work on SS, but I'm skeptical. A damaged edge means stretched material and that would work harden SS, not to mention that shrinking it back is much harder than stretching.

My $.02, Bob

If it's fairly thin, like .010, then just a sharp scissors or shears.

For thicker, decent tin snips will work fine.

When you're getting into the .040 and up range, you might want to find someone who has a shear. ;-)

Good Luck! Rich

How thick? If not too thick, you can use a sharp pair of paper scissors for straight edges and reasonable curves. I use them for

A bit thicker, perhaps tin shears such as are used in air conditioning ducting.

If yet thicker, you will need a shear -- with the gap adjusted according to the thickness of the stock.

If you are the one wanting rings of shim stock, you will need to make a guided punch to make clean burr-free edges.

I don't think that the suggested knife-edge steel against a hard rubber backing will produce your needed freedom from burrs.

Good Luck, DoN.

If that edge has to be dead flat, as for a reed valve or certain electrical connectors, I don't think a punch will do it in shim-thickness stainless. Press tools to make burr-free IC lead frames, for example, typically have tolerances of +/- 50 millionths of an inch or even closer. And the alloys used for that are a lot less inclined to draw a burr.

It's all a matter of how burr-free you have to be. But any punch to cut such thin stock cleanly requires EXTREMELY close punch-to-die clearances. Unless the punched shape is round and the die can be turned, it's a bugger to make one.

Nitric acid will not dissolve 300 series stainless. Fact is, it's 300 series that's used to contain and dispense nitric in volume. (55 gallon drums and smaller).

Harold

Last time I went to buy some, the guy just looked me and said, "What?"

I never deal with anything with those tolerances, so can't help.

Steve

--How thick is it? If it's thin enough you can do it with a paper cutter; makes a nice clean edge on brass anyway..

Depending on thickness, a pair of scissors works well for me. There is also 'plastic' shim stock that works pretty well and the thicker sizes are easy to cut with scissors to boot.

Wes

You cut *stainless* shim stock with scissors? I've cut brass that way, but I've never tried stainless.

How thick?

Cut oversize with tin snips/scissors and Dremel/stone the burr off. Alternative, use a thin cutting disk to chew out your piece. Another alternative, use a standard sheet metal nibbler to cut the piece out, then file to your scribed line. I've used all of these methods at one time or another, just depends on how intricate the piece needs to be and how thick. Nibbler can go quite thick for shim stock, maybe not so thick with stainless as with brass, aluminum or mild steel. I've punched thin shim washers out with a Whitney punch and spent a little time with a diamond hone getting the burrs knocked back. Worked fine for gun stuff.

Stan

Wes

I was applying electricity; the passivating layer on the stainless was pretty easily breached, and then the nitric DOES attack the metal. I tried salt, too (not as effective as HNO3). There must be a good standard etchant, I've got a business card that's marvelously detailed, etched in stainless, from Acu-Line (phone 206-634-1618 in Seattle, WA, USA).

I would be all gungho to do those with a CO2 laser.

Then I want a laser CNC machine anyway. "Yes, dear I did need to spend five grand on EBAY fir a laser for my little CNC machine. I needed to engrave some stainless steel business cards." LOL.