View Full Version : Greenlee-type punches?

03-30-2005, 12:45 PM
I have a need to make holes in aluminum panel about 1/16" thick. The holes need to be 1.375" diameter, with flats on opposite sides that are parallel and 1.125" apart. "What?" you say? There will be two in the panel, to allow mounting of a standard US 110v electrical outlet behind the panel.

I know Greenlee makes all kinds of round punches, and even a few odd ones, like for a DB25 connector of the type used for PC serial ports and such. Has anyone heard of one for an electrical outlet?

Thanks, all.


Whether it's broken or not, I can probably fix it - if by "fix it" you mean "make it different than it was"

03-30-2005, 12:55 PM
Cripes - never mind. It's called a "double D" punch (hee hee), and Greenlee makes many sizes. Doh! [Admin - you can delete this thread to save space, if you want]

Whether it's broken or not, I can probably fix it - if by "fix it" you mean "make it different than it was"

J Tiers
03-30-2005, 01:53 PM
I wanted one that did both holes at once for a double outlet, and ended up making it. Didn't want to fuss with alining 3 ways (distance x distance y and rotation) every time.

Turned out OK for a first attempt at tool and die making. Works.

03-30-2005, 03:26 PM
Do tell! You have plans for it? Would you consider renting it out or some kind of trade?
This is exactly what I need to do, and I have to do it about 20 times.

Whether it's broken or not, I can probably fix it - if by "fix it" you mean "make it different than it was"

J Tiers
03-30-2005, 10:12 PM
Here is a pic of the punch. If you look at it closely, the flat sides are pieces let into the main body of the female half. They are about 3/16 or so thick.


The female part was first bored out full size with allowance, using toolmaker buttons to locate the holes. Then it was milled for the let-in pieces. All O-1.

The punch half was alined on holes also laid out with buttons. The punch parts were turned to size as rounds, and attached to the backing plate using the alinement holes for position. The alinement holes were then bored out for the punch screws, and the flat sides were milled off to size. The top was given some shear off to both sides from the centerline of the punches, so as to make the cutting pressure reasonable.

I didn't use any dowel pins, although that would have been a good idea. I didn't have any place to put them, initially, so I let the screws do the work, along with the milled places where parts were let in.

I made the punches slightly too small, so I have a very little filing to do when I use it. No more than I might have to do anyway, to clean up edges, although I'd use a deburring tool otherwise.

If anyone knows what a "Lindsay timer" is, the punch was made for modifying and updating them.

[This message has been edited by J Tiers (edited 03-30-2005).]

03-31-2005, 12:14 PM
That's great. Couple o' questions, tho.
How'd you get in the corners of the receiving side?
What's the material?


Whether it's broken or not, I can probably fix it - if by "fix it" you mean "make it different than it was"

J Tiers
03-31-2005, 01:52 PM
If you look at it closely, the flat sides are pieces let into the main body of the female half.

All O-1.

What that means is that if you look closely at your arrows, you will see faint lines showing that the straight parts are a separate piece. A receiving slot was milled into the main part of the die to take the strips forming the straight sides.

The corner is the meeting of the bored hole and the straight side of the let-in strip.

The entire die is about 3/8 thick, the strips are about 0.156. The backing plate is 5/8.

03-31-2005, 03:19 PM
Ah, I'm truly inspired to steal your design,
maybe improve on it. I've already arranged to obtain the raw material. Thanks, J Tiers.


03-31-2005, 03:53 PM
that's trully neat.

I think I would have rotary tabled it out with an endmill and gone back to file the corners by hand, only because I would not have thought to "let in" the flats.

where do the slugs come out? do they just fall out?

J Tiers
03-31-2005, 05:30 PM
That was my first idea. But the filing machine was on the blink, and I hate hand filing. So I looked in my punch and die making books and there was the idea.

This is a Greenlee type loose punch and die, so the slugs are taken out when the punch is removed from the work.

If it were a press punch, it would have to have had holes through the die (and a number of other features). And, I probably wouldn't have been able to have the "undercut" left by the let-in pieces. They might have led to the blanked-out scrap pieces jamming up.

The shear on the punches tends to let the scrap come back out no problem, because they get folded a bit, reducing their width.

I would change a few things, but since I use it just once on each modded unit, it is really just to avoid separate punches or a lot of nibbling and filing. That it does fine.

[This message has been edited by J Tiers (edited 03-31-2005).]

03-31-2005, 09:16 PM
Just one more dumb question, obviously from a neophite: What exactly does "O-1" mean, or stand for? It sounds like a common designation for a well known metal. I was actually hoping for an answer like "it's low-carbon steel" or "it's Grade-X tool steel" or "it's kryptonite".
Please don't tell me it's Unobtainium.


03-31-2005, 09:26 PM
It is a type of high carbon steel known as drill rod. Oil is the quenching medium. Drill rod is called silver steel in the UK. It is an inexpensive and high quality steel that has many useful applications around the shop. I stock O-1 and W-1 in sizes up to around 1.5".
O-1 - Oil hardening drill rod.
W-1 - Water hardening
A-1 - Air hardening

[This message has been edited by Joel (edited 03-31-2005).]

J Tiers
03-31-2005, 11:22 PM
A note, I used the 3/8 thick strip O-1 material for the punches and die, but I used ordinary cold-rolled or the like for the backing plates. Only the punch and die pieces were hardened.

I made and fitted pieces, then hardened them. I did not surface-grind the die or punches, I don't have access to a surface grinder.

AISI type O-1 ground flat stock, gotten from Victor machinery, as I recall.

[This message has been edited by J Tiers (edited 03-31-2005).]

04-01-2005, 12:08 PM
Very nice! I'm surprised that Greenlee doesn't make a punch similar to your.

04-01-2005, 01:33 PM
Well, they do, but it's only a single-hole, so the user has to be careful of alignment and spacing issues. That's why I like this one so much.

Paul Alciatore
04-01-2005, 10:06 PM
Greenlee does indeed make the Double D in that size. I have one. I got it on E-Bay in a lot of 6 or 8. I wondered what the heck it was for for about a couple of weeks until I looked at the outlet behind the workbench and the light bulb came on. And, yes it only does one hole at a time, but it does not require any presses, just a wrench or two.

If you want to rent it, e-mail me off board.

Paul A.