since there isn't a metal forum...

[shock_]

Zero metalworking experience here.  How to cut two neat 7mm by 14mm holes in 1mm ex-PC case steel?

I want to mount two USB sockets, headphone jacks and a volume knob on a wall of my cocktail. I have a nice convenient pair of USB sockets from a motherboard which mount on a case expansion slot cover as shown below. 

What I want to do is re-mount those to a piece of steel I will cut from a salvaged old PC case, jigsawed to size - as well as mounting the other sockets/knob through it.

What tools and/or technique should I use to achieve this fiddly nonsense?  I can almost guarantee I don't have the tools but if I know what to ask for I might be able to borrow something

[TOK]

A metal punch is typically used to make circular holes in sheet metal, but you're looking to make a pretty small size, and you have to drill a pilot hole for it anyway. I think if I was going to try to do it, I'd drill the end holes with a 7mm drill bit then connect them by cutting out the center with a rotary tool (Dremel).

[shock_]

Sorry that image wasn't clear - the holes are rectangular, the two-focused ellipse is the outline of the plastic part of the sockets behind it.  But the Dremel idea is probably the go.  They're basically like a tiny router, no?

Come to think of it, is actually using my router completely insane, assuming I've got a sufficiently small bit somewhere for it, and accept the fact of about a 1mm radius roundness in the corners?  This is 1mm thick el-cheapo computer case steel.  I'd hate for it to land in my eyeball or something.

[ChadTower]

Yes.  Trying to use a full size router on a piece that small is asking to have it embedded in your torso.

[ScottS]

Yes.  Trying to use a full size router on a piece that small is asking to have it embedded in your torso.

I would expect that trying to use a woodworking router in sheet metal is just generally a bad idea. I wouldn't even consider it!

My approach would be to drill a starter hole in one corner of the rectangle, then use a jigsaw with a metal cutting blade to cut the rectangle. Stay just inside your marked lines.

The edges may be a bit gnarly, so you'll have to file them smooth and to the line. Remember: files cut in only one direction; if you pull them back and forth you'll ruin them pretty quickly. In the U.S. files are rated as follows: rough, coarse, bastard, second cut, smooth, and dead smooth. You'd probably use a bastard file until you get close to the line and then a smooth file to clean it up at the end. Filing will create a burr on the top or bottom side of the piece, so be sure to knock that off with the smooth file before trying to use it.

Ideally, you'll want to clamp the piece in a smooth-jawed metalworking vise while you're filing it. If you don't have access to one, a wood- or leather-lined woodworking vice could also be used. Don't use a serrated-jaw metalworking vise... unless you want the piece to look like crap! In any event, the metal needs to be well-supported while you're filing it. If it's moving all over or making lots of noise, you'll probably get bad results.

[ScottS]

BTW, feel free to ask metal-working questions here. I have experience with welding (MIG, TIG), some metalworking (shears, brakes, pedestal grinders, horizontal band saws, cold saws, abrasive chop saws, plus a few other things) and have recently been doing some machining (Bridgeport mills, engine lathes). Cool stuff!

[TroyO]

Maybe something like this would do the trick? It seems to be made for exactly that type of thing.

http://www.radioshack.com/product/index.jsp?productId=2289712&cp

[shock_]

Cheers for the tips! Drill, jigsaw and metal blades I have.  Nibbling tools I shall investigate.  One day there will be a photo of a finished product and hopefully no bandages.

[mountain]

I would suggest using Aluminum. It is easily found at hardware stores and is very easy to work with. It drills easier than steel and is also easier on the drill bits. I would be afraid that the steel from a PC case would be too thin. One snag with a tool and it could bend the piece.

[hng]

Plasma Cutter.

but you probably don't have one of them. If you have a compressor, you could use a regular ol' cut off wheel.

If you don't, you could get an electric  4 1/2" angle grinder and put a cut off wheel on it. It would take all of about 30 seconds.

You could also use the li'l cut off wheels on a dremel, but they break real easily.

[SavannahLion]

A word of advice.

If you elect to use the Dremel. Cut from the back of the metal not the visible front.

I built a (never completed) Badtz Maru custom PC case and I didn't realize the damn case was a mix of steel and aluminum. The steel panels were powder coated and like a dumb ---Cleveland steamer---, I cut from the visible side. Because the steel was so hard, I had to use a combination of bits including brittle cut-off wheels. Every time the Dremel would snag a bur, a bit would shatter or when trying to drill a new hole, the tool had a tendency to jump the metal and skip across the front, gouging out chunks. The amount of work I put in trying to sand down the powder coating and smooth out the gouges almost negated any worth in the project. 

When clamping the work down, make sure you put it down on a clean surface. By the time I got to the aluminum portions, I learned my lesson and cut from the back side, which was entirely negated because the metal shards from all that cutting gouged the soft aluminum on the front. Again, more work sanding and smoothing out the gouges. 

[NightGod]

Nibbler tool, definitely. I made something very similar to what you are doing in the past and a nibbler tool was perfect for it, just need to be able to drill a hole big enough to get the tool into place to get started.

[ScottS]

Plasma Cutter.

but you probably don't have one of them. If you have a compressor, you could use a regular ol' cut off wheel.

If you don't, you could get an electric  4 1/2" angle grinder and put a cut off wheel on it. It would take all of about 30 seconds.

Hint: 7mm x 14mm = 0.28in x 0.55in.

I slipped a decimal when I did the conversion earlier and was thinking that dimensions were 10X larger. For holes that small, I'd probably go with a Dremel tool. Nibbler might work too, if the nibbles are small enough.

[ChadTower]

Seems like he'd just eat it.

[hng]

Plasma Cutter.

but you probably don't have one of them. If you have a compressor, you could use a regular ol' cut off wheel.

If you don't, you could get an electric  4 1/2" angle grinder and put a cut off wheel on it. It would take all of about 30 seconds.

Hint: 7mm x 14mm = 0.28in x 0.55in.

I slipped a decimal when I did the conversion earlier and was thinking that dimensions were 10X larger. For holes that small, I'd probably go with a Dremel tool. Nibbler might work too, if the nibbles are small enough.

If its a small hole, you don't have to use all 4 1/2 inches. 

but yeah.. for a hole that small, Its not worth it to buy that big of a grinder. But if you have one lying around, it would be real quick and easy to do.

[bfauska]

Actually, a 4 1/2" cutting wheel would not go deep enough to cut through the metal w/o cutting a line longer than 1/2" (the larger of 2 dimensions on the rectangles in question.)  You would need a 1" disk to make it work, and even then you are only cutting through at the center of the side, and not all the way to the corners.  I realize you could cut from the backside and not care about the too long cut, but you would end up with sharp metal around your hole and if you could pull off one clean hole I would be amazed, let alone 2 on the same piece of steel.

I think that to do this w/o a specialized punch (which a local metal shop may have, so it wouldn't hurt to ask around) you will have to use a very small nibbler or drill a pair of 1/4" holes side-by-side and connect them with a file.

If you had the piece cut to size, marked and ready to go a shop with the right tools would probably make the holes for you for a few bucks, off the books on a break kind of thing would be best.

[shardian]

A dremel is your weapon of choice here. Use a diamond wheel for the hard stuff.

[shock_]

dremel with which attachment?  Sorry still newbified.

[ChadTower]

If its a small hole, you don't have to use all 4 1/2 inches. 

That's what she said.

I agree, Dremel is the way to go, and one of the best tools you'll ever get.

[shardian]

dremel with which attachment?  Sorry still newbified.

A diamond wheel. Much better than cut-off wheels that you spend more time replacing due to breaks than actually using.

[TroyO]

For a hole that small, drill a hole and hit it with a file. It will go pretty quick, and you'll be able to keep it clean and neat.

I think the dremel is overkill and more likely to hose things up.

[t8erbug]

If you plan on doing many projects, an air file is a somewhat cheap investment ($20-$30 harbor freight tools) and it makes short work of metal, plastic, and wood. You can get very coarse to very very fine files. Air compressor need first.

[DEMENTED]

check out http://www.makezine.com/extras/15.html for some ideas.

[shock_]

Wow - I never knew so much debate could be had about two small USB holes   Great link, too, DEMENTED - thanks.

The deed is done; I found a square bastard file at the hardware down the road that turned out to be exactly 7mm.  A few minutes of waggling through a pilot hole later and I'm the proud owner of a piece of very-handmade-looking, but usable steel plate. Cheers for the plentiful suggestions!