Cutting a large round hole

I need to cut a hole in some 2mm alloy sheets. Its for a computer as I want to add an extra 120mm fan.

I was just going to but a hole saw from screwfix **LINK**

Any advice ie should I sandwich between 2 pieces of wood

Have you got a boring head, could do it with that.

I would, then it should be easy.

Make sure it is well clamped, if it can move, it will.

Neil

I have Jason but it not big enough

Cheers Neil

Mark the centre, scribe the circle with dividers, drill, saw, chisel the centre away, file to the scribed line. Shouldn't take more than 10 minutes or so in aluminium.

Andrew

Edited By Andrew Johnston on 21/11/2018 19:08:23

Jason, I think the hole saw option will be quicker and neater

.

Do you have a link to a reputable supplier, please, Carl ?

I have yet to find a decent modern equivalent to the original Abrafile.

MichaelG.

The hole saw will cut a decent hole if used in a drill press and the plate clamped to a wood backing piece, I have done thousands over the years, usually freehand in a pistol drill.

The saw you link to will need an arbore to mount it though, a cost effective method would be the drill and file method.

Not a long job in aluminium.

When I was making the splashers for my Pansy loco I made steel mig welded "cans / tubes" from 1.6mm thick steel sheet. The diameter from memory was around 5". I used a cheap treppaning tool in the drill press, clamped onto a sacrificial piece of wood on the table. Cutting half way through and turnoing over to complete the cut. Filed away the burs before going on to weld it to the rolled centre piece worked out well.

Should be a dodle with aluminium.

Alan.

I smear tap/die lubrication which helps the hole saw work.

Martin P

You don't need a big head, just a tool out the side, this quick video was done for Ron in his boring head thread but I just used scraps of 2.5mm ali as an example.

Edited By JasonB on 21/11/2018 20:31:52

Edited By JasonB on 21/11/2018 20:46:06

How about a tank cutter, treppaning tool?

If you don't know what a treppaning tool looks like it's the one bottom left. That would do the job too.

The tool Jason refers to as a trepanning tool is probably what John and I call a tank cutter, originally used in an old fashioned brace, or very low speed power drill.

Emgee

You need a longer tool.

Just had a look at the photos in the boring thread and now see what you mean. Will check my boring tool to see it the bit will fit the way. At the mo the tool bit points down

Edit:  yes it has  the tool it is triangular like this https://www.chronos.ltd.uk/acatalog/info%5fXP162%2ehtml

Edited By petro1head on 21/11/2018 23:07:30

Bosch make hole saws with fine pitch teeth, specially for cutting holes in thin sheet metal. Not cheap, though.

Marcus

The tank cutter type tool works well until you break through, i find attacking from both sides is helpful but you will probably still need to tidy up with a file. Hole saws seem to make a hole but holding to a size is not their strong point. If you don’t mind a bit of filing then jig saw most of the waste and file to size.

Mike