Cutting a 25mm square hole in steel

[jenevers]

Is a Dremel capable of cutting through 6mm steel? 

I need to cut a 25mm square hole. 

Any advice?

[Bee]

Might be, if not then a jigsaw might be better with a couple of new metal cutting blades and a few drops of oil. If you can get a 25 mm drill bit with a reduced dia. shank to fit a normal electric drill (search on google) then that would do it then file the corners out. I think whatever you do it will end up with you filing bits out and using bad language.

[springy]

or 25mm hole saw followed with a file

 

springy

[Dr Bob]

On Monday I used a dremmel to enlarge a battery cable connector hole from 8mm to 10mm so it would fit on a 10mm stud. It took maybe 5 mins grinding and broke one 'bit'. You could do it with a dremmel but it would take weeks with my box of drills files etc. Be interesting to know if there are better quality drill bits or files that would 'survive' the 20,000rpm or so.

I'd go with a drill, hacksaw and then a decent hand file.

 

[Machpoint005]

removed -- OP is not cutting gypsum board!

Edited March 6, 2019 by Machpoint005

[BEngo]

25 mm hole saw and a four square file.  10 minute job to do.  More time to mark out.

Less if you don't 0mind rounded corners: drill 4 corner  holes then remove centre with hole saw.  Tidy up with a file.

[Alan de Enfield]

29 minutes ago, jenevers said:

Any advice?

"Get a man in" to do it.

 

The right equipment will make it an easy job.

You can skin your knuckles, burn out your drill / jig saw waste a coupe of days or pay someone with a portable plasma cutter to do it in 10 minutes.  2 minutes.

 

Sealey PP40E Plasma Cutter Inverter 40Amp 230V (£300)

Inverter power supply fitted with plasma cutter control circuitry. Features digital Amp display and two LEDs on the front panel indicating overload and mains power. Supplied with a 4.6m plasma torch, 2m earth cable, 2m gas hose and regulator. Ideal for cutting steel, stainless steel, galvanized steel, aluminium, copper and brass. IP21S Rated.

• Inverter power supply fitted with plasma cutter control circuitry.
• Features digital Amp display and 2 LEDs on the front panel indicating overload and mains power.
• Supplied with a 4.6m plasma torch, 2m earth cable, 2m gas hose and regulator.
• Ideal for cutting steel, stainless steel, galvanized steel, aluminium, copper and brass.
• Max. Cutting Thickness: 11mm.
• Weight: 9.4kg.
• IP21S Rated.
• Model No. PP40E

Technical Specifications

• Model No PP40E
• Power Output: 8-40A
• Duty Cycle: 60% @ 40A, 100% @ 30A
• Maximum Cutting Thickness: 11mm
• Air Requirements: 250ltr/min
• Working Pressure: 43.5-58psi
• Absorbed Power: 6.2kW
• Supply: 230V*
• Insulation: F
• Protection: IP21S
• Weight: 9.4kg
• Replacement Consumables:
• Electrode, Short (Pack Qty): PP40E.E (x5)
• Nozzle, Short (Pack Qty): PP40E.N (x5)
• Diffuser (Pack Qty): PP40E.D (x5)
• Safety Cap (Pack Qty): PP40E.SC (x2)
• Note: *To achieve maximum power a 32A supply may be required.
• Nett Weight: 9.4kg

Edited March 6, 2019 by Alan de Enfield

[system 4-50]

Depending on access for the jigsaw, drill 4 corner holes then jigsaw, using the jigsaw to clean out the corners as well, no filing except for tidying up.  Prefer this to using a hole saw.  Curiosity - what do you need the square hole for?

[Alan de Enfield]

2 minutes ago, system 4-50 said:

Depending on access for the jigsaw, drill 4 corner holes then jigsaw, using the jigsaw to clean out the corners as well, no filing except for tidying up.  Prefer this to using a hole saw.  Curiosity - what do you need the square hole for?

Apparently he has a round peg that needs fitting !!

[RLWP]

1 minute ago, system 4-50 said:

Curiosity - what do you need the square hole for?

Now, there's a thought. A 25mm square hole is about 35mm across the diagonal. So a 35mm hole saw would be easier

 

For that matter a 30mm saw and just file in the corners might work

 

A Dremel - no

 

Richard

[Machpoint005]

14 minutes ago, RLWP said:

Now, there's a thought. A 25mm square hole is about 35mm across the diagonal. So a 35mm hole saw would be easier

 

For that matter a 30mm saw and just file in the corners might work

 

 

That's dangerously close to practical geometry! Whether it works or not depends on the width of the flange (or whatever) that stops the whole thing falling through the hole.

[David Mack]

You need a square hole drill bit.

 

[Joe Bourke]

Bosch T123X Jigsaw blades are the best steel cutting blades i have ever used.

[Fly Navy]

Using a dremmel to cut thru 6mm is akin to chopping a tree down with a nail file............

 

Use a 35mm drill bit used for cutting thru steel - square off the edges with a suitable file.

[dor]

Using a 35mm hole saw might reach into the corners, but will be too wide for the desired 25mm square.

I would probably drill the corners and use a jig saw to cut between, or maybe a 25mm hole saw if access is good.

[David Mack]

10 minutes ago, Fly Navy said:

Using a dremmel to cut thru 6mm is akin to chopping a tree down with a nail file............

Or a herring.

 

[WotEver]

1 minute ago, dor said:

Using a 35mm hole saw might reach into the corners, but will be too wide for the desired 25mm square.

I would probably drill the corners and use a jig saw to cut between, or maybe a 25mm hole saw if access is good.

There would be a heck of a lot more filing to make a 25mm circle into a square than there would be sharpening up the corners of 4 holes in the corners, so my preference would be the 4 holes joined up with a jigsaw. 

[Kieron G]

You could chain drill it around the edges with a small bit starting with the corners. knock the centre out then file the high spots flat.

[WotEver]

57 minutes ago, Fitter kieron said:

You could chain drill it around the edges with a small bit starting with the corners. knock the centre out then file the high spots flat.

Even less filing and no jigsaw

[Sea Dog]

No!!! Stop it with the ideas - I've already sold 43 tickets to folk keen to watch someone cutting a 25mm square hole in 6mm thick steel with a Dremmel!

 

[RLWP]

4 minutes ago, Sea Dog said:

No!!! Stop it with the ideas - I've already sold 43 tickets to folk keen to watch someone cutting a 25mm square hole in 6mm thick steel with a Dremmel!

 

You might with this one: https://www.ebay.co.uk/itm/LOVELY-OLD-VINTAGE-AMERICAN-MADE-DREMEL-WITH-TRANSFORMER/123673181444?hash=item1ccb7efd04:g:HLwAAOSwAn9cfBRp

 

Richard

[Murflynn]

my dad joined the RAF in 1941 and qualified as a skilled fitter (RR Merlin rebuilds in the field).  One of the tests was taking a 1" thick bar and cutting a hole in it 1" square, and then making a 1" cube to fit in hole in all different positions, with minimal clearance.  Hard and difficult work.

[jenevers]

4 hours ago, David Mack said:

You need a square hole drill bit.

 

Amazing. I knew there must be an answer. Unfortunately that obviously can’t be used as a hand held device. I’m going down the 4 holes joined up by a jigsaw route.

[WotEver]

1 hour ago, jenevers said:

I’m going down the 4 holes joined up by a jigsaw then a bit of filing route.

Fixed that for you

[Fly Navy]

Brilliant thread???

 

Herrings can be quite dangerous in the wrong hands!

I've seen it all now - a drilled SQUARE hole!!!!