Cutting 6inch holes in 1.2 mm SS sheet

As part of a boiler casing I have 2 6 holes to cut in stainless steel sheet, 1.2 mm thick, The sheet is just over 600mm by 400mm, and the 2 holes located close together near one corner.

I did the last one (but on thinner 0.9 mm ) using tin snips. For this one I are trying to decide between chain drilling and cleaning up the edge. or using a cheap scroll saw.

What would be the best blade to use to use on 1.2mm stainless. I gave up on the first one as it just vibrated all over the place.

Or what are your handy tips for chain drilling to simply knock out the center and have minium clean up of the edge.

Mike

See if your local engineering shop has a nibbler. a sheet metal or duct shop should have one. it only take a few minutes and if its the punch type ,there will leave no distortion. if you are near north manchester I will do it for you .

Trepanning the holes with a big tank cutter worked for me on a similar task some years ago. Bottom speed on the drill I had then, around 40-50 rpm I think. Went to some effort getting things clamped down so the sheet and cutout didn't move. Probably ex kitchen cabinet chipboard baseplate with another sheet screwed on to hold the main material down. Rough hole in cover sheet to accommodate tank cutter and several screws to hold waste in place.

Clive

Plasma cutter?

I recently cut 9" holes in 18g stainless with my handheld plasma. A tapered hole was cut in a wooden batten to accommodate the cutter head and a screw was inserted at t'other end to provide a pivot.

The cuts took less than a minute each.

Edited By charadam on 16/03/2016 18:11:10

Thanks Clive , I might have trepanning tool lurking about.

Thanks Michael for the offer of doing it for me, but i am also looking for a low cost option and my car to Manchester and back will be about 20 quid

Tank cutter any use ?

Dennis

(didn't see mention of trepanning tool - must get an appointment at Specsavers !)

Edited By Stovepipe on 16/03/2016 20:52:02

It's a bit more than £35, but you can use one of these over and again.

They say it will do 1.2mm stainless.

I have one and it absolutely rips through 1mm plain steel sheet.

Neil

Bought one of those nibblers that Neil linked to. It just eats .06" mild steel....

Pete

RDG do a cheaper nibbler at around £25. I have one and it works well. See:

http://www.rdgtools.co.uk/cgi-bin/sh000001.pl?WD=nibbler&PN=TWIN-HEAD-SHEETMETAL-NIBBLER-740%2ehtml#SID=241

Mike

Neil/Mike/Pete

Presumably a template is needed to guide the nibbler when cutting a neat round hole. I had to use a straight edge to cut a straight line with a nibbler, which worked nicely, but what a mess it made. Ear defenders essential as well.

Robbo, my nibbler from RDG came in a nice case complete with a circle cutting attachment, see second picture here:

http://mikesworkshop.weebly.com/nibbler.html

This will cope with holes from 20 mm up to 250 mm diameter. However, it would be easy to modify, by adding an extension piece, so that it could cut bigger circles.

It is easy to cut straight using a straight edge as a guide. You are right about the mess. The little crescent shaped cut outs go everywhere and get stuck into shoes. I made a nibbler table, see link above, for small precise work and this keeps the nibbles all in one place.

I do not find the nibbler so noisy unless cutting a poorly held sheet that resonates.

Mike

thanks all, I has just bought a nibber from RDG. I can always find a reason for buying a new tool.

I have a couple more boilers covers to build next year so decided to buy.

Mike