View Full Version : Guillotining 6 mm Brass: How much warping to expect

22nd Aug 2008, 01:39 PM
Over in the HOMEMADE TOOLS AND JIGS ETC. I have been putting together a Bulk Brass Order (http://www.woodworkforums.com/showthread.php?t=75033). We are intending on getting a single sheet of 260 Brass Alloy, for making infill style planes to share amongst each other.

We however need the sheet cut up into strips to share amongst members.

The question is how we cut it up?

George White says will guillotine it for us for about $60 - $80 for the 1800 x 900 mm sheet. However the sales guy says that the guillotine will cause the brass strips to warp and twist into banana shapes so much that the brass will roll around. Now is this an exaggeration, or fact? If guillotining the brass will cause it to warp and twist, how much will the brass strips warp and twist by?

The other option I am looking at is water jet cutting, since laser is out? I sent away for a some quotes and the first quote back was insanely expensive, he wanted $20 per cut and $50 programming. Is this a reasonable price to pay for cutting brass via water jet?

Another question is about laser cutting, I am told that laser cutter will not cut brass because the brass it so reflective and the laser reflects back into itself and gets burned out. However, just theoretically speaking could you coat the brass in non reflective finish and then cut it?

If anyone has a suggestion as how best to cut the brass plate up and who could do it, it would be much appreciated.

*EDIT* The brass is located in Melbourne.

22nd Aug 2008, 01:58 PM
Guillotining would be a last resort I would think.

I have some 6mm brass (not sure what grade), cut by guillotine, and as you say it is a bit of a banana shape. The edges left by the cutting action are not pretty also,deformed and stressed, there will be a bit of wastage to clean it up to square edges again.

I think I remember seeing a Boilermaker cut round shims out of 6mm brass plate using a Plasma cutter. That might be a cheaper option worth looking into.

EX's Timber
22nd Aug 2008, 01:58 PM
The sales guy is correct, it will warp especially at 6mm thick, in fact it will even slightly compress it along the cut edge as well

22nd Aug 2008, 02:11 PM
How much "kerf" will plasma cutter take? And who would do plasma cutting?

What about a metal bandsaw?

22nd Aug 2008, 05:58 PM
I went and found a piece of my brass plate that was guillotined, a piece 50x6x600mm, when holding one end flat on the bench, the other end was about 30mm up off the bench with a slight twist also. Not sure how hard this would be to straighten?

The edges were not as bad as I remember also, requiring 1-2mm to be removed to bring back to 2 sharp edges (closer to 1mm).

A plasma in the right hands would probably waste 2mm per cut, it will look a bit like an Oxy-cut, but a lot neater (less clean-up) and a lot less heat generated, the pieces will be hot, but you will still be able to pick them up (test first though).

Any Boilermaking/fabrication shop these days would have a plasma cutter, though the ones that I have seen/and/or used, just have a handpiece/torch that you hold freehand.
So the neatness and straightness of cut will come down to the skill of the operator.
Maybe newer ones can have a guide fitted to do a straight cut, I dont know. Its about 8 years since I had access to one where I worked at the time.

A bandsaw might be a good option.

23rd Aug 2008, 05:50 PM
Pity you are not a bit closer - this is where my 1 mm kerf cut of wheel on my table saw works well although it's probably a bit slow for the amount you need done - bandsaw might be OK.