Seeking help (cutting 3mm aluminium plate)

[Richard RogalewskiParticipant @richardrogalewski21509]

Hi. I hope this post is kosher.

I live about 3 miles from Wakefield in West Yorkshire and before Christmas last year I promised to make a TRF receiver for the kid next door.

I need to cut a 3mm thick 300mm x 235mm plate across it's longest length (to make the chassis). I was going to make a mini table saw so I could cut it myself, but at this rate the kid won't get the receiver any time soon.

Anyway, I'm seeking favour: Is there anyone near me who has the means and willing to cut this plate? I don't fancy trying to cut it with a hacksaw blade. Perhaps you have a mini table saw, or whatever that will make light work of the cutting.

Thanks for reading. Rich

[Richard RogalewskiParticipant @richardrogalewski21509]

[Gone AwayParticipant @goneaway]

Jigsaw with metal cutting blade and clamped-on guide?

[KWILParticipant @kwil]

If it is alumium then an ordinary tenon saw will cut it.

[Richard RogalewskiParticipant @richardrogalewski21509]

I was looking to make something like this micro table saw, but a bit bigger table area. But, could be months before I make it. I've got a fractional motor. But that's all at moment.

http://metaltronics.wordpress.com/2011/05/16/micro-table-saw/

 

Edited By Richard Rogalewski on 27/03/2014 20:22:52

[JasonBModerator @jasonb]

If you have the ability to cut the slot for the blade, then why can't you just cut a longer slot all the way through your 3mm Plate?

I would just turn the blade 90degrees in a hacksaw frame and you should just be able to reach the middle of the plate. or leave as is and come in from both ends and the cuts will meet in te middle if you angle the saw.

[Richard RogalewskiParticipant @richardrogalewski21509]

I'm not really a model engineer so there is lots I don't know, including cutting by hand tools.

Let me just psyche this out contemplating use of hand tools.

I think what people are recommending is make some kind of jig or tool to aid in cutting with a hand tool.

Okay, so giving it some thought, lets say the plate is clamped on a wood block.

If I then clamp two bits of wood or metal either side of the cutting line as guides, I could use a tennon saw placing the saw between the two guides. This would mean I'd get an accurate cut. I'd just saw away until the tennon saw got through. Whether an engineer would do that, I don't know, but it seems preferable to messing about with a hacksaw and no jig.

Edited By Richard Rogalewski on 27/03/2014 20:48:10

Edited By Richard Rogalewski on 27/03/2014 20:50:27

[Richard RogalewskiParticipant @richardrogalewski21509]

Actually I like the idea of that jig. Not thought about making that before. I could knock it up in an afternoon.

Just wondering what tennon saw I'd need. Got to cut aluminium. Must look at products.

P.S. Not sure I'm going to find a tenon saw that will cut aluminium.

Edited By Richard Rogalewski on 27/03/2014 21:08:40

[Richard RogalewskiParticipant @richardrogalewski21509]

I can see me making my own tenon saw, with a regular hacksaw blade.

[Michael GilliganParticipant @michaelgilligan61133]

Richard,

Have a look at the Eclipse 55 Sheet Metal Saw

… Made for the job.

I don't think they are listed anymore, but they do come up on ebay, and it would probably be easy enough to copy the design.

MichaelG.

[julian atkinsParticipant @julianatkins58923]

i can cut 8" length with an ordinary hacksaw blade. with a 12 tpi or less blade it should take you no more than 5 – 10 mins.

cheers,

julian

[WALLACEParticipant @wallace]

I would just clamp a straight edge (a piece of wood would do ) to the ally to use as a guide and use a jigsaw.

Would also cover the section being cut with masking tape to avod scratching the surface.
The problem with cutting using a guillotine is that it does compesss the metal
sligtly along the edge so it’s no longer dead flat – albeit quick and the cut dead straight
.

If you have an orbital sander, that can give a nice finnish to it as well.

W.

Edited By WALLACE on 27/03/2014 22:02:59

Edited By WALLACE on 27/03/2014 22:06:24

[Billy MillsParticipant @billymills]

Do you really NEED 3mm plate? In 60 years of electronics I have never ever seen any chassis that thick, 1mm would be plenty to support bits for a TRF. Once you put a couple of bends in thin sheet it is more than rigid for the use. It is not as if you need any great stability for a TRF with realistic Q values. Go THIN and save elbow grease.

Billy

But I do like sheet saws and nibblers…….

[russellParticipant @russell]

try the 'dual saw', the new kid on the block with contra rotating blades, would, according to the ads, be able to do this quite easily. Having played with one a little, i suspect the ads are true that much at least.

but i agree with Billy, 3mm is overkill for a radio chassis. 1mm will be fine, and a hacksaw will cut this easily.

Finally, the last chassis i started (but didnt finish) was based on an aluminium baking tray. dont get a non-stick one though!

just some thoughts.

russell

[HopperParticipant @hopper]

Hacksaw is all I use for such cuts. Steel or aluminium.

[JasonBModerator @jasonb]

I think Kwil was assuming you had a tennon saw already, The ones for wood will cut Aluminium if needed but rather than going out and buying one use a hacksaw.

If you feel you need a jig it does not have to be complicated, clamp two strips of wood to the sheet with a 1mm gap between and use that to guide your hacksaw. Cut in from both ends and you will get 150mm depth each time and the cut will meet in the middle

I'm not keen on using jigsaws against a fences as the blades seldom track true to the base and the blade wants to wander

Edited By JasonB on 28/03/2014 07:44:30

[BazyleParticipant @bazyle]

Of course you used to be able to get ready made chassis in .8mm ali from places like Henry;s radio.

I think you were nearly there with the wood guides but I would suggest two pieces of 2×1 either side of the metal along the line. Note that is either side of the metal not either side of the cut line. This gives you a support for the metal to stop it rattling and a flat surface to press teh blade against on both sides to keep it level and straight.
A tennon saw from a car boot sale will do. Also one of those modern disposable panel saws.

Finally while I think it is generous of you to make this for the kid may I suggest you involve them significantly in the build. They will then have a vested interest in the item and value it far far more. Some of the cutting and filing, then coil winding and soldering. Other wise it will be a 5 minute wonder when it isn't as tunefull as and iplayer.

On a model boat forum there are terrible examples of this wasted opportunity. There is a particular simple tug design specifically designed for beginners. A kid comes on the forum and says ' I like the look of that' so someone offers to build him one – completely defeats the purpose. On top of that they now produce instant fibeglass version of it .

[Bill RobleyParticipant @billrobley]

Hi Richard.

For 3mm aluminium plate, you can, if you have one, use a wood bandsaw, it tends to be a little noisy but it works beautifully. I use mine all the time.

Do also bear in mind that the thinner sheet aluminium tends to be very soft and will easily gum up drill bits, files and the like.

I hope this is of some use to you, now or in the future.

Bill.

[Ian S CParticipant @iansc]

At one time the only aluminium sheet I could get was 1/8" plate from a boat builder, so I built radio chassis, and the boxes to fit it in from that, but half that would be much better, or even thinner.

A modern cross cut saw would have no trouble, and a guide made of wood, would ensure a straight cut.

Me, I'd cut it using my metal cutting band saw, about a 30sec job. Ian S C

[IDPParticipant @idp]

Whatever you cut it with life would be much easier if the blade is lubricated. Paraffin is about the best, white spirit will do but for a one off something like WD40 or similar from the local bargain shop is excellent.

Regards.

[WALLACEParticipant @wallace]

Another idea.

Find a small engeering works with a power guillotine and pay them a visit with your best smile and a crisp ?5 note…it’ll take a minute to do and any decent place will do it there and then.

W.

[Neil WyattModerator @neilwyatt]

Hand tools don't mean hard work if they are sharp and used as a steady pace.

My vote goes with those suggesting a hardpoint woodsaw with a piece of wood as a guide. A few minutes to make the cut, and then a couple of minutes draw filing (pulling a file sideways along the edge) to tidy up.

For 4" cuts in 3mm mild steel (that's 1/3 as long) I can do the job in a couple of minutes with a hacksaw, cutting to a line then draw filing.

A jig saw is no faster than a handsaw and can be harder to get a straight line, IME.

Your mileage may vary!

Neil

[Richard RogalewskiParticipant @richardrogalewski21509]

Posted by Michael Gilligan on 27/03/2014 21:35:41:

Richard,

Have a look at the Eclipse 55 Sheet Metal Saw

… Made for the job.

I don't think they are listed anymore, but they do come up on ebay, and it would probably be easy enough to copy the design.

MichaelG.

I see that the Eclipse 55 is just a regular wood saw kind of arrangement with a hacksaw strung underneath as the cutting edge. Should be easy to make from an old tenon saw, or some metal plate.

[JasonBModerator @jasonb]

But you would need to cut the metal plate to make the saw first Bit of a Chicken and egg situation

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Richard Rogalewski on 31/03/2014 19:45:21:

I see that the Eclipse 55 is just a regular wood saw kind of arrangement with a hacksaw strung underneath as the cutting edge. Should be easy to make from an old tenon saw, or some metal plate.

.

Exactly what I was implying.

Incidentally; note that [unlike the tenon saw] there is no "Back" on the 55.

MichaelG.

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