Cutting straight lines in sheet steel

[Boris113]

I have an old stainless steel chef's table that I would like to chop up and use for inner door cards on my 2-part 90 doors.

Whilst in this case I plan to use a jigsaw with a metal blade and the guide that clamps on, what would be the best way to cut the steel perfectly straight if the edge wasn't straight in the first place, meaning that the parallel guide on the saw was no use?

Is a standard steel jigsaw blade suitable for stainless steel also?

Thanks in advance,

Harry

[AndrewHorsfield]

I would use a 4.5" grinder with thin cutting discs. You can get ones specifically for Stainless Steel

[Eightpot]

Yes, don't bother with jigsaw blades, they don't cut straight at all. 1mm slitting discs in an angle grinder give a nice straight cut.

[Boris113]

Great stuff, thanks chaps

Do you use something like a piece of wood/steel clamped onto the sheet to act as guide or just go for it free-hand? I'm reasonably practical but it never seems to go ruler-straight. Previously I've used 2.5mm disks and no guide with the grinder but they have always gone off slightly at an angle, although I fear that is my fault rather than the tools

Harry

[Phantom]

Plasma cutter and clamp a wood straight edge to the job for your guide

[Cynic-al]

A plasma cutter would make a lovely job if set up properly

How big and thick is it? A fabricator might be able to slice it with a guillotine for a couple of quid.

[ejparrott]

Try your local fab shop, if it's a little one like the one I use for bits for my engine, they'll stick it through there and then and won't ask for anything - i usually chuck them some beer money anyway

[studmuffin]

If the sheet has been separated from the frame a guillotine is the way to go. As suggested try a local fab shop or small steel stockholders who sell sheared steel blanks. Their is no real difference shearing stainless or mild steel. They can all easily achieve +/- 0.4mm in accuracy and over the dimensions you need the straightness will be pretty much cock-on.

[Boris113]

Thanks all

I'd love a plasma cutter but can't justify the expense, insurance for the 90 is bad enough considering I'm only in the country for 8 weeks a year! May have a ring around some mates to see if I can borrow one though

The steel can't be any more than 2.5mm and I'd just need 2 rectangles approx 3 feet x 1.5 to line the doors so that should be do-able with a guillotine, come to think of it I think the local agricultural engineers may just have one!

Cheers,

Harry

[Spearos]

I've done similar to this but with some 1.5mm stainless sheet I used to make a cover for one of my workbenches. I used a 4.5" grinder with a thin slitting disc.

Clamp a piece of angle iron as a guide and make your first cut - gently rest the top (flat) side of the disc against the angle iron and move along the whole length first, this will 'cut' a shallow groove that will help you keep the cut in a straight line. The key thing being the flat side of the disc must lay flush against the guiding angle iron, i.e at 90 degrees to the sheet.

Then, from this straight cut/line just make two lines at 90 degrees the correct distance apart and cut as before... Need I continue?

Ok, not as quick or easy as a plasma, guillotine etc but take your time with setting things up/measuring/checking and it's doable to a decent standard.

HTH

[Ex Member]

The thin cutting disc works fine and is cheap. Clamp a piece of steel to the piece to be cut and run the cutting disc along it.