Punching holes in (very thin) gauge metal by hand

[Jessica Pierce-LaRose]

My wife has a little side business repurposing and refinishing old things she finds, selling them at craft festivals and on etsy. (No, we're not the folks painting handsaws) One of the things that's folks seem to really like that surprised us was some soap dispensers made from old Ball jars; we pop the glass from the lid, and make an appropriately sized hole in the tin lid to attach the pump mechanism. (We're using the old tin and glass seal lids, not the modern two piece ones) I've been using a hole saw in my brace with a little wooden jig to hold them and support the backside of the lid as I saw through it, and then de-burr the flash left behind. The other half of the jig has a little thing to make a centering dimple to help get the hole in the right place. I think the two hole sizes we're using are 1" and 1 1/2", but I'd have to check that.

We're not making a million of these, but enough that it seems like there's probably a better/faster way of doing it. I suppose getting my drill press into the equation would make things better, which is my next step, to modify my jig to fit on the press. But the material is pretty thin, so it seems a decent punch would work, which seems like something I could make or purchase, and probably be the quickest route. Given the thickness of the material, it seems like a punch that I could just strike with a hammer would work okay. But I know nothing about this sort of task, or where to start looking for these supplies. The only sort of punch I've seen for this type of thing is the kind where you drill a hole and then thread the punch through and screw it down to punch from both sides, that seems like it might be almost more time than just drilling the big hole. I know a few people here are knowledgable about this stuff, so I thought I'd ask if anyone had any advice. A drill press, and an old, smaller arbor (that I use for guitar fretting) are probably the only two "big" tools that I have that I can think would be applicable to this . . .

[Mike Henderson]

You can make a very clean hole with an electrical knockout punch. Greenlee makes a lot of them but I don't know what sizes they make. They also make some hand punches. Using a knockout out punch is not that quick, however - maybe not as quick as what you're looking for.


Anyway, search on Greenlee knockout punches - or even just Greenlee punches.

Mike

Here's (http://www.harborfreight.com/knockout-punch-kit-91201.html)a set that includes a 1" punch.

[Jessica Pierce-LaRose]

Thanks Mike, that's also probably just something I'd find a lot of use for if I had one kicking around - I do enough weird little electronics projects that end up needing big holes for components.

I'm still thinking with the very thin nature of this tin, that something that would work without the draw stud might work, and thus be even faster. Of course, I bet I could mash a hole big enough for the draw stud with a hammer a big nail or a drift pin or something. That hole wouldn't need to be pretty, just enough for the draw stud to get through.

[Jessica Pierce-LaRose]

Looks like an "arch punch", designed for leather working might be my ticket . . . might be worth trying as well.

[Jonathan McCullough]

Tin is pretty soft. You could probably drill a hole through the side of a piece of appropriately-sized pipe, so that it looks like a Greenlee punch, then sharpen the edges on the inside of the pipe. You could then drill a hole the size of the pipe in some hard wood, and use the pipe and wood like a punch and die. You could get fancy and have a top piece with locating pins so the punch would be automatically aligned with the die.

[Dave Beauchesne]

Joshua: I am with Mike on this one - a hole that size in tin will be a bear to drill ' nicely ' with a hole saw or anything except maybe a step drill. I am a HVAC mechanic and do a lot of sheet metal work; you almost have to have a punch and die like a knockout punch to do the job cleanly. A piece of pipe and an appropriate die will likely give a poor result. I just noticed I can't tab over or enter to the next line - good luck - Dave Beauchesne

[george wilson]

Buy some old chassis punches off of Ebay, They were used when tubes were installed in radios,etc.. I saw a set for sale a while back. Except for tube enthusiasts(of which there ARE quite a few making guitar amps),they are obsolete. Drill a 1/4" hole,assemble the male & female punch parts on either side. Tighten them with a wrench. Clean hole.

[Keith Outten]

Construction electricians use a hand punch tool to make holes in metal studs that is perfect for your task.
.

[John Coloccia]

I don't believe he will find a stud punch in the proper size as they're sized for conduit.

The first thing that came to mind when I read this was Greenlee punches. That's what George is describing, btw (though not necessarily made by Greenlee) and if you find them used you'll save some money.

[mike holden]

Check the machinist tool catalogs. There are commercial hole punches for sheet stock. We used to make our own, two blocks of steel, Indexed with dowels, holes drilled and reamed to size to make the "button" and dowel with a slight concavity on its face (picture running a dowel straight into a grinding wheel, this leaves two points of contact to start the cut) as the "punch" Punch and button are the toolmakers terms for the tools which pierce metal. You place the sheet metal between the two blocks, centering the hole and insert the punch and with a quick rap of a heavy metal hammer, bang! you have made a hole.
Mike

[Bill White]

George has it. An electronics supply would have a chassis punch. I've got one, but it is not as big as ya want.
It uses a pilot hole, then a couple wrenches to tighten the punch.
Mine is a GREENLEE 3/4". USA made too. 'Course I've had this thing for years. Used it when I was building guitar amps. Anybody remember tube type amps?
Bill

[Jim Koepke]

Anybody remember tube type amps?

Yes, I used to actually play with tubes when I was young. I have and have used Greenlee type punches. I inherited most of them from my dad. He used to make tube circuits as a contractor back in the 1940's and 50's.

I think these are not what the OP wants. As I recall he didn't want to have to drill a pilot hole.

Most of the hole plier type cutting punches might not have enough clearance for the lid to fit.

What is needed is something to do a finished job quickly, accurately and safely.

All of my ideas deal with more work than is practical and may not work.

jtk