Metal working

Dear All, I am currently building a wooden piece of sculpture and am beginning to look to make it out of metal - principally Aluminium. The
question I have is, how difficult is a large ellipse to draw/cut out of the above material e.g. Would an engineer have to buy specialised equipment (very large ellipse guides?) and also is the process of making stuff like this costly to do as I would like an engineering company to do most of the work. I know that a high degree of precision costs more but my project doesn't need that much. Thankyou for any advice. Sorry for the large post.
Simon.
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Simon Griffiths wrote:

It depends on the size of your project, and the thickness of the metal sheets/plates involved.
Up to 4 x 2 m shouldn't be much of a problem for cnc laser/water cutting. If it is much bigger, you need to find specialists with large enough machines or assemble it from several smaller pieces. Don't even think of doing it with a electric saw or something similar. Laser cutting doesn't cost a lot of money, and the resulting precision is worth to pay for. You can save additional money if you do the CAD work by yourself and give it as DXF files to the cutting shop.
The cost depends very much on the material thickness, call a cutting shop to get the approximate prices.
Laser cutting is useful up to 6 mm for aluminium, waterjet cutting takes up to 80 mm (data from the last shop that did work for me)
The whole project will be costly if an engineering company is working for you. The cutting will take the smallest part.
Andreas Rutz
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Drawing an ellipse is a joyful experience: In wood: nail two pins. Tie a loop of string bigger than the distance between the pins. Place an indelible pen in the apex of the triangle of string, and run it round to form an ellipse. Longer string equals less eccentricity.
A sheet of aluminum would take the same process, using perhaps two stickers instead of nails.
Hand cutting or nibbling aluminum alloy is straight forward in thin gages. Perhaps 3/32 inch (94 thousandth inch) would be an upper limit to hand cutting. Then a scroll saw (and patience) would work for thicker sheets. Much above 1/4 inch, I'd use a shop.
Brian Whatcott Altus OK
On Mon, 12 Jul 2004 00:18:15 +0200, "Andreas Rutz"

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Abrasive waterjet will cut aluminum from 0" to 10 inches thick fine, (though the cutting gets really slow as you get thicker, especially if you have sharp corners. Typically the practical limit of thickness for cutting aluminum with an abrasive waterjet is about 2-4" or so.)
To learn more about the capabilities of water/abrasivejets, visit:
http://www.waterjets.org
(That's my web site)
To find a place that can do it for you, visit:
http://www.waterjets.org/waterjet_jobshops.html
or
http://www.omax.com/job_shop_match.html
Hope this helps. Feel free to send me an email if you have questions ( snipped-for-privacy@waterjets.org)
Carl. http://www.waterjets.org

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Dear Simon Griffiths:

the
the
post.
Precision costs money. You can always sketch the ellipse, transfer it from a CAD print (hammer and punch), or use two "pins" and a string to form your ellipse. Then use a plasma cutter or jigsaw (if its not too thick) to cut out the shape.
David A. Smith
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snipped-for-privacy@btopenworld.com says...

Depends on how big/thick the aluminum is. Is this ellipse to be cut out of aluminum plate? How thick? Overall dimensions? With a few precautions and limitations, aluminum can be worked with most woodworking power tools -- circular saw, band saw, jig saw, router, etc.
It's not difficult to lay out an ellipse accurately enough if all you require are woodworking tolerances. In other words, it only has to look good.
A little more info would help to make a recommendation.
Ned Simmons
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