Chassis making (Nibbler)?

[YT2095UK]

I`v bought some really nice 1.5mm x 250mm x 500mm sheet Alu, a couple of assorted step drill bits and am making a sheet metal bender, but I was wondering what would be a good make of nibbler for cutting the stuff?

anyone have experience in this and know a good t`n`t method/tool?
most of the ones I`v seen are 1.2mm only, and I don`t really want to pay more than 20 quid.

[Sean Williams]

Sadly when it comes to sheet metal tools, money is king.

Buy a cheap tool, and get cheap results, and in the process, loose faith in ever getting it to look right.

16-18swg Aluminium (assuming the grade isnt anything too daft) will cut nicely with a good pair of tinsnips, or hacksaw with a fine blade.

There used to be a sheet metal nibbler called "Monodex", there are cheap ones that are similar available, but they are hard work, and leave a nasty burr on the sheet you are cutting if not set correctly.

Any of these drill mounted things are work of the devil - they tend to go where they want to, and make one hell of a mess, they are however quite cheap!

If you can afford it go for a good set of compound lever tinsnips, there are three in a set, LH cut, RH cut and straight. (dont let this confuse you - they will all cut straight, left or right....) - Practice on scrap material, and take small bites with the shears, keeping a good even motion and speed - you will end up with a sheet that needs minimum after cutting finishing.

HTH
Sean

[Sideband]

I seem to remember our old Metalwork teacher using a guillotine for cutting ally. I took several sheets in and made chassis up during lessons. Lovely straight edges with that!


Rich.

[Aub]

Hi

I use a pair of Gilbow tin snips, made in Sheffield, that I bought about 25 years ago. I would imagine that they would cost quite a bit now, if you can still get them.

Aub

[Oldtimer74]

The problem with all tin snips and Gilbows is that they tend to leave a slightly jagged edge with the sheet not exactly flat. Anything above 20 SWG I cut with a hacksaw, or better still a metal cutting handsaw as there is no frame to get in the way. Finish off with a dreadnaught file ALONG the edge. No one will ever know it wasn`t cut on a guillotine.
Pat G3IKR

[John M0GLN]

Unless you've a lot to do, have you tried a local sheet metal workshop? I took a piece of 1.5mm stainless sheet to a firm near me, and they cut it to size for nothing, but obviously you can't keep going back too often.
For aluminium sheet at home I generally use either a jig saw or hacksaw, to finish the edges after sawing I use a woodworking plane, a steel one, not a wood one, it gives a superb finish.

John

[davidw]

I cut soft metals aluminium brass copper etc using a fine tooth blade in a conventional woodworking bandsaw (Ryobi) and have found it works very well.A new one won't be in your budget but they often crop up cheap in the small ads.

[Mike Phelan]

I tend to use a Monodex for short runs, but it soon wears your fingers out unless you use leather gloves. I also have a similar but smaller Eclipse device.

The drill-powered ones are just about acceptable, but you really need a second pair of hands and clamp the sheet with a metal bar as a guide.

I agree with what Pat says regarding the Gilbow, excellent as they are - mine is a few decades old now. You don't get a flat edge.

A pair of heavy bits of angle iron used as vice clams can be used to finish the edge with a Millenicut or Dreadnought file.

[Paul Stenning]

Originally Posted by jcaines

Unless you've a lot to do, have you tried a local sheet metal workshop? I took a piece of 1.5mm stainless sheet to a firm near me, and they cut it to size for nothing, but obviously you can't keep going back too often.

If you slip the guy who did it a fiver for a couple of I'm sure you'll be welcome back!

[ppppenguin]

Originally Posted by Mike Phelan

A pair of heavy bits of angle iron used as vice clams can be used to finish the edge with a Millenicut or Dreadnought file.

This may be a stupid question from somebody who is pretty lousy at metalwork but...

If you've got a piece of ali, say 12" * 8", and you want to clamp it in the vice to file an edge smooth how do you do it? It's all going to hang out of one side so the angle irons aren't going to clamp the outer edge very well and it'll all flap about as you file it.

[Station X]

You apply a 'G' cramp to the ends of the angle furtherest from the vice, or drill them for a nut and bolt. I prefer to use two bits of 3" by 2" wood for that sort of jib.

I cut sheet material with a hacksaw or tinsnips, then file to the marked line.

[YT2095UK]

I think I`m going to have to go the Jigsaw route, but use broken hacksaw blades shaped to fit it (a simple dremel job), I have tin snips but they tend to make a hell of a mess on long cuts with the ends turning up etc...
I considered clamping it, then scoring it with a stanley knife and then bending it back and forth waiting for metal fatigue to snap it, but the jigsaw seems the more elegant method.

it`s a pity we gave my old Vono bed to the scrap man a few ago, the base was All made of angle iron and I never thought to keep a length of it.

[Sean Williams]

You can get blades for cutting metal for most jigsaws - not the best method for cutting long straight lines though.....

[Aerodyne]

My thoughts, for what they are worth: hacksaw is OK provided you clamp thoroughly - I clamp to the bench with the sheet between thick blockboard panels. Circular holes are best cut with Maxi-Q hole punches. These give a very neat finish for valveholder holes etc.
For other internal holes such as drop-throughs for transformers, a metal-cutting blade in a fretsaw is neat but laborious. Series hole drilling (chain drilling) is a little quicker but much filing and cleaning up of the edges is needed. When drilling, always drill with scrap timber beneath as a support to minimise distortion of the sheet.
Finally, when I taught metalwork I made scoring tools from worn-out files by heating the tangs to red heat, bending and sharpening to a vee shape. This tool when drawn over the aluminium toward you along a straightedge provides a deep groove which facilitates folding and separation, easily cleaned up afterwards by drawfiling.
-Tony

[Mike Phelan]

Originally Posted by ppppenguin

If you've got a piece of ali, say 12" * 8", and you want to clamp it in the vice to file an edge smooth how do you do it? It's all going to hang out of one side so the angle irons aren't going to clamp the outer edge very well and it'll all flap about as you file it.

Jeffrey
I use angle that is longer than the metal I am bending or cutting, and like Graham does, clamp the extremities if necessary.
HTH

[YT2095UK]

I have to ask, with regards the hacksaw, How does one go about cutting a sheet that is 250mm wide without the bridge getting in the way?
is there some sort of attatchment you can buy that makes it single ended (like wrapping a cloth or some leather around one end of the blade) or something, or is it cut all in one along its entire length at the same time, not leaving much room to actually saw with?

[Station X]

Most hacksaws have a facility to turn the blade at right angles or 45 degrees to the frame. That will enable a piece about four inches wide to be sawn off. With the blade in the normal position you can cut from both ends of the line.

Failing that go as far as possible with the hacksaw and then use one one the Eclipse handles designed to hold a hacksaw blade as if it were a keyhole saw. Some people like to reverse the blade so it cuts on the back stroke with this arrangement. It prevents the blade bowing and breaking.

[YT2095UK]

Nice! that makes sense now as I have a Very old adjustable hacksaw (1950`s) that will do exactly that, and I`m also one of those that reverses the blade for single ended work, i`ll have a look for one of these Eclipse handles, as it sounds much better than putting a nut/bolt through the end hole of the blade and wrapping some leather around it

[mhennessy]

I've always struggled with metalwork using "traditional" hand tools and techniques - partly because it wasn't taught well at school so am largely self-taught. As a result, I'm quick to try techniques that might seem peculiar at first, but bear with me...

Aluminium is softer than oak and beech, and this got me thinking about using woodwork power tools. I discovered that my simple Bosch jigsaw (with a fine-toothed metalwork blade of course) is much better at cutting aluminium than wood! To clean up a cut edge, I clamp the piece between a pair of extruded right-angle sections that I rescued from a skip years ago, and file the work flush. As I've had these sections for 20 years, they're starting to wear out now

When I bought a router, the inevitable experiments started; given the appropriate attention to safety, a router makes excellent cuts on aluminium. You're only limited by the ingenuity of the jigs and guides you can make - but a simple straight edge would clean up the result of a jigsaw rough-cut. I've attached a picture of a simple milling operation I did a few years back; this was just a straight edge and some clamps, and safety glasses. More pictures on my homepage...

Routers can be had for £30, so this must be worth considering. Safety must be the main concern, and I'll happily expand on that subject if you like...

Since then, I've got a mitre saw and a basic table saw - both of which do a superb job with a fine-tooth blade (which a woodworker would already have).

Never had much luck bending metal though - for that reason I try to use angle sections and thick stock to make boxes. I do a lot of "skip diving"

[brianc]

I've just finished the chassis for my Simplex TV which required holes for octal and B9G valve bases. The corners I cut out with a hacksaw having drilled 3.5mm holes in the corners and I bought some Bosch holesaws of the appropriate dimensions and used them in my pillar drill which has a back-gear. The resulting holes were fine but the speed of rotation must be low. I asked a friendly metal company if they had an offcut of about the right size and he said "No, but I can make you one". Now that's real kindness.
Cheers
Brian