easier way to cut a square hole for xmfr

[PRNDL]

I'm considering building another amp, and am wondering what the easiest way is to make a square hole for the power transformer.

The last time I used a jigsaw followed by filing the edges to fit. It wasn't hard, but took time and was fairly annoying.

Is there another method that is easier than the jigsaw and file?

Any recommendations are appreciated.

[hotbottle]

It's one of those jobs I don't like either.

One other way is to use a nibbling tool, but that can take a while for a big transformer.

Another crude method is to drill a series of small closely spaced holes around the perimeter of the desired rectangular hole, then cut between the holes with a cold chisel, then file.

[Jeb-D.]

I gave up doing my own metalwork and now just use www.frontpanelexpress.com

[benchtester]

I am not sure of the material you are trying to cut, but for wood or aluminum you can use a router with a carbide burr or end mill, maybe 1/8" in diameter. Make a wood frame to guide the router to the square pattern. Make sure that the material is well attached or clamped to the frame, since the cutter may want to grab the material. Afterward, you will have 1/16" radius in the corners, which you can leave or clean up with a file.

[hotbottle]

That's it, time I bought a router.

[zigzagflux]

2nd vote for frontpanelexpress.

Never again will I cut my own. My time is too valuable. A $130 perfect panel just can't be beat.

[CarlyBoy]

I'm way too much of a tightwad to spend $130 on a panel.

A while back I had to do some duct work. Decided there had to be a better way to cut a round hole into the side of a duct in a confined space. There is! Make a square one with a dremel tool and a cutoff disc. Not hard to get nice straight lines. Don't try to go too fast or put any lateral pressure on the disc. Even the slightest lateral pressure will break the disc. This isn't a big deal provided you're wearing safety glasses. The discs come in mutlipack at your local hardware store.

[PRNDL]

It's aluminum.

I may use a router or rotozip to do this, but was wondering about it.

[Sherman]

Depending on the thickness of the metal you may be able to use a 'nibbler'. This is a tool that cuts rectangular holes by cutting out little rectangles of metal. It has handles like pliers that you squeeze together. Advantages- cheap ($10 US), easy to use. Disadvantages- big holes can make your hand tired!

I use them in thinner chassis for square holes for things like IEC inlets.

[Ty_Bower]

Originally posted by CarlyBoy
Make a square one with a dremel tool and a cutoff disc. Not hard to get nice straight lines. Don't try to go too fast or put any lateral pressure on the disc. Even the slightest lateral pressure will break the disc. This isn't a big deal provided you're wearing safety glasses. The discs come in mutlipack at your local hardware store.

I made the hole for the PT on this chassis using a Dremel with the cutoff wheels. It came out looking real nice, but took forever. The aluminum is 1/8" thick. I must have gone through at least two or three discs on each side of the hole. Definitely buy the cutoff wheels in the biggest pack they sell (25?). Go for the "heavy duty" ones, too. I wouldn't even dream of attempting this on a steel chassis.



I've been told the Gyro brand cutoff wheels are about 100 times better than the Dremel. You can find them here:
http://www.gyrostools.com
# 11-32156 and grab their mandrel model # 80-1800