Brass Shape Punching?

[Dee Gallo]

Does anyone here know how to punch small shapes through thin metal like brass shim stock? I know my laser won't do anything, but who can make a punch I can use with a hammer to punch out holes like a teardrop shape or similar? Would it be a machinist? Tool & die maker? I don't know where to start looking. Also, does Cermark stick to brass?

And please don't tell me to buy a YAG or something, that's not happening! hahaha

Thanks, dee

[Dave Johnson29]

Does anyone here know how to punch small shapes through thin metal like brass shim stock?

Hi Dee,

Not sure if I am allowed to self-promote on the group so I will email as well.

The brass sheet you refer to is called shim-stock and it is rolled to thickness and therefore work hardened. It can be annealed by heating and cooling slowly or quenching in water. Seems a paradox I know, but that's the way it is.

You will need metal punches and die plates. I can make these for you if you give me dimensioned details of the shapes you want.

Harbor Freight have one for doing round holes and of you check this link it will give you an idea of the die plate set up.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95547

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91510

Both are limited by the throat depth but I can make the plate type any size you like within reason. The second type is more versatile but more limited on throat depth.

[Dee Gallo]

Thanks Dave, I'm going to email you now.

:D dee

[Margaret Turco]

You can get punches from Wagner die supply here http://www.wagnerdiesupply.com/punches.html or Pace Punches or Ameriken.

You could ask them to squeeze one into a teardrop or whatever if it doesn't have to be really precise. Custom shapes are expensive from these guys though. I agree with Dave that you'll have to cut against metal, and even so the edges may roll-under a little bit.

[Mike Null]

Dee

Depending on how many you have to do you can use a drill press and a file to shape the holes. If you have a lot to do this method isn't worth the effort.

[Dee Gallo]

Margaret - thanks, that's a possible source... I wish they'd show prices on their website though.

Mike - I'd like to get away with as little handwork as possible. Not so much laziness, but arthritis. And I'm looking at 100 or so. But thanks, that is a usable suggestion if I need to make one of something.

I've gotten a few leads on people who have inductrial lasers and am still looking for a waterjet person. I have no idea how much this kind of work goes for, so I need to do research!

thanks, dee

[Margaret Turco]

Well, I don't know what size punch you need, but anything up to .5" diameter should be around $6.00 for a round punch if I remember right. If you have a local steel rule die maker you could check with them, too. They can bend rule and weld it for you although they probably have a minimum charge. My local die maker has a $50 minimum.

[Dave Johnson29]

They can bend rule and weld it for you

Margaret I do not think it will be that simple. To cut brass sheet cleanly you need a punch and a die. As in, a Male-punch the shape you want to cut out and a Female-Die in that same shape but a few thousandths of an inch bigger all round. Both punch and die need to be hardened, tempered and ground to a sharp square cutting edge.

Those two parts then need to be held in a die-set or something similar to the second HF item I mentioned above. I have designed and made many hundreds of such dies as a toolmaker in my early work years. Round holes are easy as you can see from the HF links I gave above.

I really cannot see a steel rule punch cutting 0.012" thick work hardened shim brass for very long. My guess would be 2 or 3 pieces then it would need sharpening again.

Dee's best bet is for water jet or 1000+W CO2 laser for that quantity as a die set would be able to cut many hundreds of thousands of parts and cost a bucket of money to make.

[Margaret Turco]

I agree Dave but thought it worth mentioning since Dee is only making 100 or so. In fact, Dee, I should have asked if you are making teardrop shaped holes in something, or you're trying to get the teardrop shaped pieces....

[Dan Hintz]

Dee's best bet is for water jet or 1000+W CO2 laser for that quantity as a die set would be able to cut many hundreds of thousands of parts and cost a bucket of money to make.
Or maybe have the die itself cut using a waterjet?

[Dave Johnson29]

Or maybe have the die itself cut using a waterjet?

The internal shape of the die is not just a straight hole it has clearance about 1/16" down so it would still need some machining from the back. If you are machining the back-draw, you might as well go that last 1/16" and machine it all.

You also need the punch and that would be a difficult thing for water jet.

No quick way around it other than big laser or water jet for the quantities IMHO.

[Michael Hunter]

Thinking slightly outside the box, how about chemical etching?

It is quite an economical way of getting small thin parts made and you could get a range of shapes all done at the same time.

Just a thought....

[Brian Robison]

Dee, try contacting Jack Harper, he's on here once in a while. He did a great job of water jet cutting some parts for me a while back.

[Dee Gallo]

Dee, try contacting Jack Harper, he's on here once in a while. He did a great job of water jet cutting some parts for me a while back.

Thanks Brian, I sent him an email yesterday. I also found a place in Buffalo that might be able to help me.

:) dee

[Jack Harper]

Thanks Brian, I sent him an email yesterday. I also found a place in Buffalo that might be able to help me.

:) dee
Dee - I did not receive a PM or email, but I would be happy to help, just PM me your details and I will look it over.

[Dee Gallo]

Jack, I just sent you a PM.

Thanks for your help!

cheers, dee

[Dan Hintz]

The internal shape of the die is not just a straight hole it has clearance about 1/16" down so it would still need some machining from the back. If you are machining the back-draw, you might as well go that last 1/16" and machine it all.
Could you not just stack two pieces, with the bottom one having a slightly oversized cutout compared to the one above?

[Dave Johnson29]

Could you not just stack two pieces, with the bottom one having a slightly oversized cutout compared to the one above?

You mean for steel rule dies? Aligning the two pieces would be tough, but the blades would still need constant resharpening.

Water jet is the most efficient option here.

Either that or maybe Dee can find someone with an EDM (Electrical Discharge Machining) and have them run a stack over the weekend. I used to get some 16G aluminum parts made like that. I supplied 100 3" x 4" pieces. They would stack them 10 high in 10 piles and let the EDM work over the weekend. Worked out about a buck a piece as I recall.