View Full Version : Punching shim stock... super-thin washers

09-13-2009, 07:06 PM
I posted a while back about a source for really really thin #4 washers made from SS. I've not found a suitable supplier for a reasonable cost and I've decided to punch them myself. The question is...

Whats the difference between these two items?

("Makes perfect custom washers, shims and gaskets every time")


("Dual cutting head punch - inside and outside diameter can be punched at the same time")

09-13-2009, 07:35 PM
The Precision brand is a true shim punch set that is designed specifically for punching shim stock from steel, SS, copper, etc. The Mayhew is a gasket punch set for hole making in non-metallic material.

For what you are proposing to do, you need the first set.


09-13-2009, 08:45 PM
How thin is "super thin"? The best way to make "perfect" ultra thin washers is chemical milling. It's really easy to do. Ferric chloride will work fine on copper, brass, aluminum and stainless steel. For resist all you need a coat of thin candle wax which you can scribe with a compass. You only need to scribe one side if the material is really thin. The other side can be covered with whatever like paint.

09-13-2009, 09:46 PM
I have both sets of those punches,though different brands.

The first is for thin metal shim stock,I wouldn't try SS unless it's really thin and dead soft though.

The second is for rubber and paper gasket material.

Evan has a good suggestion and I have also had good luck with my local laser cutter cutting shims.

J Tiers
09-13-2009, 10:02 PM
The first one is the only one to have a chance with SS of any sort.

I have a set, which I have used for all sorts of shim washers, although I don't know if any SS was included. I see from the link that my price at a garage sale was pretty good, I paid $8 for the same brand punch set, apparently unused. However, I didn't get the fancy plastic case, just an OEM cardboard case.

Thin, as in a few thousandths, material is what they are for. Above 20 thou, it's too much, really, and SS could be worse depending on alloy.

Regular steel and brass, etc, they are great for.

They have no shear, at least my set does not, meaning they have limits. And, it can be difficult to see when you are perfectly centered, despite the clear top.

The second set is about the same as a set of 'arch punches", good for cutting discs of cork etc. Not quite as good at cutting holes in thicker material, and no good at cutting any metal, maybe brass, I admit to having used arch punches on 5 thou brass before with so-so results.

09-13-2009, 10:22 PM
Thanks guys... I think I'll just get that first set.

Super-thin is .0005" SS foil and .001" SS shim stock.

09-14-2009, 10:02 AM
Don't mean to hijack your thread, but I need this kind of help too.

I need 7/8" ID x 1.25OD x .008 washers myself. McMaster sells them but they are 1.375 OD (I believe) and that's too big. And they are $5 for ten pcs.

So my question is for Evan really... can your method of chemical milling work on .008" thick material (brass, specifically)

Thanks soooo much.

And I second the "don't buy the basket punches" I cut blanks out of CD-ROMS and have a hard time keeping an edge on them...SS will kill them.



09-14-2009, 10:16 AM
Ferric Chloride is the old time etchant (sp?) for PC boards.
As Evan says, you expose an active metal to FC it WILL go to work.

If you have never been around FC, don't spill anywhere you don't want a stain.

Hth Ag

09-14-2009, 12:31 PM
For 0.008" brass?
Should etch through really nicely.

Tom M.

09-14-2009, 01:25 PM
I spilled some FC on aluminum swarf one day and HOLY COW! It was foaming and fuming and heating up in seconds. I had to work fast before it really started boiling and throwing ferric chloride loaded steam around the shop.

It works great on brass. I etched these with ferric chloride and a special wax resist I developed. The brass is .010" thick


09-14-2009, 05:28 PM
Evan those turn out great. Did you do a write up on how this project? I did a search of you name and nothing came up. If you didn't is there one out there that you recommend?

Now I just have to research and find some ferric chloride. Thanks Evan again it looks great.

09-14-2009, 07:14 PM
Do a search on "chemical milling". I did post some information on it.

09-14-2009, 07:54 PM
You can make your own FC. Get some Muriatic Acid (Hydrochloric Acid), pour about a cup into a glass or plastic container and add a chunk of cast iron. It doesn't take much--About 1/2 cubic inch or less. When the iron is dissolved, presto--Ferric Chloride.

tony ennis
09-14-2009, 08:09 PM
How accurate/flat do your washers need to be? How many different sizes do you need?

09-14-2009, 09:42 PM
I only need ones that will pass a number 4 screw and have an od of about .25, but they need to be to shim stock tolerances.

I just ordered that punch set, we'll see how it goes.

09-14-2009, 11:25 PM
Put a piece of scrap steel in your drill press vice.drill a hole the size you want to punch for the die.Do not move it.take the drill bit out, grind the shank flat for the punch.put drill bit back in with cuting end up inside chuck and shank down.Leave the drill press OFF! place the blank on the die and pull the handle sharply.If makeing washers cut the od first.this helps center the hole.AND watch your fingers.