Drilling a square hole into metal sheet. How?

[rick_172]

Not as daft a question as it first appears!

You know how you can get drill bits for wood that have an attachment over them to create a square hole, well can you do a simliar thing for putting a square hole in metal? Alternatively, can anyone suggest the best way to go about this, considering the metal is about 2-3mm thick.

I hand it over to you ever resourceful PH'ers!

Cheers

Rick

[xiphias]

Dremel it.

[Frik]

Depends how small the fillets in the corners need to be.

[paulie-mafia]

what type of metal? if it's aluminium and relatively thin, use a dril to make a pilot hole, then use a jigsaw with the correct blade or a set of sheers. if it's thick, hard metal, then bloody hell i don't know!

[Jon C]

Hydraulic hole punch should do the trick. Quick tip, look up "Control Panel Manufacturers" as an alternative to sheet metal workers and such, as they should have a selection of cutters which will do the trick. Might do it one lunch time for you fairly cheap as well...

[sparkythecat]

The thing that puts a square hole in wood is a mortser.
It does this by utilising a drill inside a hollow square chisel.

The drill cuts a round hole, which is all it ever can do and by forcing the sharp square chisel down, the corners are cut out making a square hole.

You can't easily drive a chisel neatly through metal in the same way and would need a hydraulic machine press.




>> Edited by sparkythecat on Tuesday 31st January 21:47

[rick_172]

Frik said:

Depends how small the fillets in the corners need to be.

Good point. I'm looking to create a hole 10mmx10mm. It'll either be in steel or iron, it depends on which is most freely available, preferably steel. I'd prefer to find a homemade method so that I can do it a few times, if I have to get it done by a third party then so be it.

[J1mmyD]

No, like Sparky says, you can't - but depending on how large and how neat the square is you want a punch should be able to do it.

[thebluemonkey]

Time to fire up the plasma cutter me thinks.

Edited to add, plasma won't work that size.


>> Edited by thebluemonkey on Tuesday 31st January 21:52

[m1spw]

1. Series of holes in a line, then file down the edges?

2. Dremel

3. 4 holes, 1 in each corner, then band saw to cut alone the edges.

[rick_172]

sparkythecat said:

The thing that puts a square hole in wood is a mortser. It does this by utilising a drill inside a hollow square chisel. The drill cuts a round hole, which is all it ever can do and by forcing the sharp square chisel down, the corners are cut out making a square hole. You can't easily drive a chisel neatly through metal in the same way and would need a hydraulic machine press. >> Edited by sparkythecat on Tuesday 31st January 21:47

Yeah I'd guessed that would be the case. I just wanted to use it as an analogy so that people understood what I was trying to get at!

[vixpy1]

Have you tried explosives?

[madbadger]

You can't comfortably drill a hole diameter that's less than the thickness - assuming mild steel or alumnium. High strength steel or stainless will cause more problems.

So if you want a corner radius less than anout 2-3mm you will need to punch it or laser cut it. This will get the corners down to about 1mm rad.

A sheet metal work place will be able to do it but otherwise a bit of fiddling at home with a dremmel should do the job.

[williamp]

I remember rading about this a while ago. You use a special drill bit which looks like...well..er...

Imagine a triangle, but with curved, not straight edges. Then along the curved edges they are cut away to show a drill bit "face" to drill with. The use a drill with a moveable chuck, and the bit is allowed to move around, creating the hole,.

Or use a press like someone else suggested.

[Balmoral Green]

Am I missing the obvious? why cant you just drill lots of little holes in a square pattern, then file the edges, and the corners too to make them a nice neat 90 degrees.

[BliarOut]

Either chain drill as has been suggested, or get one of these from your local tool shop. About £20 and no press needed.

[rick_172]

Balmoral Green said:

Am I missing the obvious? why cant you just drill lots of little holes in a square pattern, then file the edges, and the corners too to make them a nice neat 90 degrees.

Thats definately an option, just a bit labour intensive! I'm trying to find out if it can be done in one go.

[m1spw]

Ok, router with a toughened drill bit in it (maybe coated in titanium or something?), then just use it as a makeshift dremel if you don't have one? Shove it in a vice somewhere, and away you go. Just watch out for bits of drill bit breaking off, they f**king hurt I can tell you

[BliarOut]

rick_172 said:

Balmoral Green said: Am I missing the obvious? why cant you just drill lots of little holes in a square pattern, then file the edges, and the corners too to make them a nice neat 90 degrees. Thats definately an option, just a bit labour intensive! I'm trying to find out if it can be done in one go.

Then look up a bit, there's the definitive answer

[madbadger]

Balmoral Green said:

Am I missing the obvious? why cant you just drill lots of little holes in a square pattern, then file the edges, and the corners too to make them a nice neat 90 degrees.

Except drill a big hole (10mm) then drill some small holes, rather than lots of small holes.

Saves a bit of time.