Metal punches for detachable power cords?

[Rodgre]

I think I brought this up on various forums in past years, but I still haven't found the solution I was looking for.



Does anyone know of a standard metal punch that will cut a hole the size of a typical IEC AC receptacle? I've managed with a drill, nibbling tool, and file on some light metal, but I would like to find something that will do the (w)hole deed in one shot, and be able to cut something thicker, like the wall of an old army ammo box that I'm building a power supply into.

Any thoughts? I've never used a punch and I don't really know how they work, but I'm assuming you drill a hole, put two halves of the punch on either side of what you're punching, and you tighten them until they cut through. Is this sort of true?

Roger

[John Lyons]

You have the theory correct about the punches.
If you can find them the punches for something like that are big $$$.
Most folks use nibblers, files, etc as you mention.
You can always drill 4 corner holes and use a jig saw witha metal blade to cut between them.

John

[Rodgre]

Thanks John.

It seems that I will have to continue the drill, nibble, file route. I had an idea that they wouldn't be cheap, but I hoped there would be a solution in the less-than-$50 range. I have a friend at a signmaker's shop, and I know that they have punches there, so maybe I'll ask for a favor.... 

Roger

[The Tone God]

I have seen punches for this shape but while I don't remember the actual price I do remember the price being stupid high and not worth it for the amount of use I would give such a tool. Also punches like that are generally setup of for thinner metal and not a die cast box.

Andrew

[e178453]

I actually have a punch for this, made by a friend who works in tool and die. He did a nice job, but it only cuts up to .05" thick metal.  He looked one up in a catalog and it is almost $300.  I also am a machinist and had idea we could make and sell them for $50 or so, but there is a lot of work involved, including heat treating.  There is a tool that will make square corners on a drill press or mill, think I should look into this as there is a lot of interest in an easier way to make holes for IEC sockets on amp making forums.
scott 

[BubbaKahuna]

There is a tool that will make square corners on a drill press or mill, think I should look into this as there is a lot of interest in an easier way to make holes for IEC sockets on amp making forums.
scott 

You mean like a mortise tool? I'd be hesitant to use something like that in my drill press. Once you beat up that vertical upright gear, it's junk.
Probably work a lot better in a real arbor press. They seem to take a huge amount of abuse and resistance. Of course they aren't cheap either.

Cheers

[e178453]

No, this is just a square piece of high speed steel with relief ground into the sides and sharp corners.  You chuck it in a mill spindle and run it up and down into the side of a round hole moving it outward a little at a time and it nibbles out the corner a little at a time.  Thinking  this might work in a drill press if it was just a piece of sheet metal. Well, shoot. I guess holding a chassis still while you did this would be a problem.  Never mind!
There is a market for SOMETHING that would make this task easier!
scott

[theundeadelvis]

I have always used a dremel with a high speed cutting disc. Takes maybe a minute.

[Alex C]

I have always used a dremel with a high speed cutting disc. Takes maybe a minute.

I did this as well, and also for a power supply built into an army surplus box.

[GonzoFonts]

A Dremel rotary tool to route out the "hole"?

GF

[RedHouse]

... there is a lot of interest in an easier way to make holes for IEC sockets on amp making forums....

Yep ain't that the truth. After hogging-out a few dozen of those round-corner-rectangular-holes in 16 gauge steel I started looking for a punch but have also run into the dead end.(and switched to aluminum for my chassis material)

Personally, I would prefer a punch, like a Greenlee which has the two dies and a pull-screw.