Making a hole for AC socket in a chassis

[engels]

After creating several different amplifiers from scratch I came to conclusion what's the most complicated part in the whole process.
It's making a hole for the AC socket in a chassis.
I'm talking about this little thing -


Drilling a pilot hole, than insaine noise with the jackson saw, then a file... It's a terribly noisy and time consuming thing to do.

What's your method?
I was looking if there's some sort of a punch for this hole - but haven't found it.
HEEELP!!!!

[Geek]

I use a scrollsaw and a 28TPI twist blade and lots of oil.

Before I had the saw, I would sharpen a "disposable" flat blade screwdriver and take a hammer and punch out the hole one step at a time.

These methods are no good for steel chassis though.

[Colt45]

Draw a rectangle

Drill out the 4 corners

Use a jigsaw inbetween them.

[kstagger]

Before using Front Panel Express and being stuck with my primitive tools - I used a 'Cord Strain Relief'... basically you drill a hole, attach the strain relief, thread in the cable, and then tighten the strain relief.

for an example, see page 21 of the Michael Percy catalog - I always have a hard time tracking these down via Digikey, etc

[Pit Hinder]

Why bother? Hardwire to your transformer, make sure the mains cable doesn't chafe and is as long as you need and be done! If you ever have to move house you'll fight for a place where to put up your rack anyway.

Pit

[Sherman]

How you make that hole depends on how thick the chassis is. For most Hammond chassis you can use a tool called a 'nibbler'. A nibbler has a fixed handle and a moveable handle, and you hold it vertically. At the top is a square head with a cutter which cuts rectangular holes.

Basically you drill a pilot hole of 1/4" and insert the head of the nibbler through the hole. With each pull of the handle it 'nibbles' away a flat section of metal. Square holes are easy that way. I drill the pilot hole near the edge of the desired hole and nibble around the outside to create any size rectangular hole.

[tubelab.com]

I use a Dremel tool with a small cotoff wheel. It is noisy, and makes a mess, but I can usually make the hole in about 10 minutes.

I am using a socket that also has the fuse in it. It means one less hole to make. I made the hole below with a Dremel in about 10 minutes, and the material is .125 inch aluminum. The hole is not pretty by itself, but is completely covered by the socket.

[kevinkr]

I generally drill a pilot hole and then use a nibbling tool to make the final hole, if you are just a little patient (i'm not really) you can get a near perfect square hole using this technique. (I usually don't take that much care - I figure it will be all hidden by the iec socket if I am not too careless.)

George also has a very good approach, I usually use my dremel to make larger square holes, but never considered using it for this. Definitely easier than the above, but it might require slightly better fine motor skills (hand/eye coordination) than the nibbler approach.

The nibbler is only good in most instances with aluminum up to .062" (mine won't handle anything thicker) anything thicker than this and the dremel is definitely the way to go.

I use punches pretty much for anything round larger than 1/2."

[engels]

Nibbler looks interesting - thanks, I'll give it a try!
The other methods are equally noisy and ugly to what I usually do - 1=pilot hole, 2=jigsaw, 3=file.
Hardwiring the transformer IMHO is no good. Most of the devices I build are often being carried to all sorts of concerts, performances and studios. If it was a home stereo I would use a strain relief.

I wonder why there's no greenlee punch for this type of hole. Should I write them a letter and copyright it?

[kevinkr]

There are punches for these connectors, they are hideously expensive and require a special tool. (often a small hydraulic punch tool) I am pretty sure that Greenlee makes one, and several other vendors definitely do. I briefly considered buying one, but the tool and the die would have cost me over $300 at the time which I considered just a little too rich for my blood.