Cutting 3mm mild steel

[BlackTails]

I need to make some straight cuts in some strips of 3mm mild steel.

My options:

- hand held angle grinder
- hand held multi tool with metal specific blade
- circular mitre saw with metal specific blade.

What’s my best best? I have a feeling that the circular saw will spin too fast, and that the multi tool will labour a bit. Which leaves my least favourite option: the angle grinder.

Any tips?

[geeks]

I've used a nibbler in the past for this sort of cut I would stay away from a multi-tool for this unless it was just quickly trimming something up then its the wrong tool for the job.

[droopsnoot]

^ Isn't 3mm a bit thick for a nibbler? I'm sure mine doesn't want to do anything thicker than 1.6mm.

How long are the cuts? Are you trying to cut across a narrow strip, so a short cut that you can easily finish off with a file, or are you doing long cuts that will be more of a pain to clean up? Are there lots of them? Any fabrication companies close by that might stick them in a shear for a couple of pints?

I don't know about the rotation speeds of circular saws, but I think angle grinders are usually around 11,000 rpm, unless you have one with an adjustment on it. My pet hates with angle grinders are all the sparks (which are often tiny pieces of molten steel, as my Mum discovered when I sprayed the front window when I used to repair my car on the driveway), and the rough edges they leave behind.

Edited by droopsnoot on Friday 4th July 08:48

[Doofus]

How big are the cuts?

Can you just use a hacksaw?

[geeks]

droopsnoot said:

^ Isn't 3mm a bit thick for a nibbler? I'm sure mine doesn't want to do anything thicker than 1.6mm.

Mine will do 3mm mild steel and something like 1.6 on stainless. To be fair it did what I needed it to do, if I needed lots of cuts I would see who locally could do it

[Lefty]

I’d just use a grinder but if you know a local fabricator with a guillotine, plasma cutter or water jet that’ll do it.

Depends on the size of the sheet, the length of the cut and the precision you need I suppose.

[jfdi]

Angle grinder with a 1mm cut off disc. Ensure the steel can't move and clamp something straight to it, to run (a none spinney part of) the angle grinder along as a guide/steady.

[tegwin]

Electric hand held Jigsaw with metal cutting blade and a spot of oil would give you a much better finish than an angle grinder

[JoshSm]

In the absence of better tools I'd say variable speed angle grinder, along with a diamond metal cutting disc.

The diamond metal specific discs like https://www.amazon.co.uk/Bosch-Professional-Diamon... aren't cheap compared to the basic metal discs but they are a *lot* more friendly for casual use, they last ages, and have no problems with a long cut where it might snag.

[BlackTails]

The strips are 16mm wide, 3mm thick. Cuts at 45 degrees, so 22.6mm long. The pieces will be mitred so a clean cut is fairly important.

8-10 cuts. Probably.

Hadn t thought of the jigsaw. Happy to throw that into the mix.

Edited by BlackTails on Friday 4th July 09:53

Edited by BlackTails on Friday 4th July 09:54

[SHutchinson]

I'd recommend one of these, because I like buying tools.

https://www.amazon.co.uk/VEVOR-Manual-Cutter-Inch-...

I've got one, it's great.

[omniflow]

An evolution chop saw will do that no problem. There are a couple of types - don't get the one with the really primitive method of doing 45degree cuts. They're not expensive. In use they sound like you're working towards the end of the world as we know it, but they do work.

You will need to tidy up the swarf, but a file should work for those sizes / quantities.

[Chumley.mouse]

This is one of those tools you never knew you needed till you use it. Someone gave it to me years ago ( new ) and I’ve only just got round to using it . It went through m12 threaded bar like butter, i was shocked at how easy it was with so little pressure. Its cuts 45’s too.

[RicksAlfas]

BlackTails said:

The strips are 16mm wide, 3mm thick. Cuts at 45 degrees, so 22.6mm long. The pieces will be mitred so a clean cut is fairly important.

8-10 cuts. Probably.

Hadn t thought of the jigsaw. Happy to throw that into the mix.

Unless I'm misreading it, isn't that a hacksaw job?
You could have done it by now!

[cookie1600]

A local fabricator or car body shop will whip those up for you in no time for a small amount of cash. They'll do a neater and safer job of it.

I'm lucky as we have a fabrication shop at work.

[BlackTails]

RicksAlfas said:

Unless I'm misreading it, isn't that a hacksaw job?
You could have done it by now!

I want straight cuts, which precludes me using a hacksaw to do it!

[omniflow]

Chumley.mouse said:

This is one of those tools you never knew you needed till you use it. Someone gave it to me years ago ( new ) and I ve only just got round to using it . It went through m12 threaded bar like butter, i was shocked at how easy it was with so little pressure. Its cuts 45 s too.

I'm fairly sure that's the model I said to avoid. There's another one that costs about £5 more where the body of the saw can be turned whilst the bed remains static - giving a much more accurate base for making 45degree cuts.

[Chumley.mouse]

omniflow said:

I'm fairly sure that's the model I said to avoid. There's another one that costs about £5 more where the body of the saw can be turned whilst the bed remains static - giving a much more accurate base for making 45degree cuts.

No idea how it cuts at 45 as I’ve not tried it. The clamp works fine at 90 next time i have it out i will give it a try at 45.

[TA14]

BlackTails said:

The strips are 16mm wide, 3mm thick. Cuts at 45 degrees, so 22.6mm long. The pieces will be mitred so a clean cut is fairly important.

wouldn't this give the cleanest cut:

SHutchinson said:

I'd recommend one of these, because I like buying tools.

https://www.amazon.co.uk/VEVOR-Manual-Cutter-Inch-...

I've got one, it's great.

[Chumley.mouse]

This guy does some 45 degree cuts with one

https://www.youtube.com/watch?v=WjMDP-KU3Jk


Didn’t realise how expensive they are ……. £120

Handy tool though and i will definitely be using it more often.