Cutting Brass Sheet

You can anneal brass to soften it. Some, if not all, brasses both work and age harden like copper. Once softened they should be easier to get flat in a suitable press/vice.

Just to show my age, I remember one of the Blue Peter presenters (probably John Noakes) going to the Royal Mint to do a piece on its work. Every time they did some work on the cupro-nickel they were using they had to anneal it, then clean it ready for the next process. I think it went through about 5 of these cycles before they were finished.

Martin C

I cut thin sheet brass or aluminium with a BK3 bandsaw (which is probably the grandfather of all the 3 wheel bandsaws on the market) with slow speed attatchment fitted. BUT always put a piece of scrap plywood under the metal, so that both are cut together.

In the first editions of Gerald Wingroves superb and unique book; 'The complete Car Modeller' there is detailed a very clever little tool made from a piece of industrial hacksaw blade and shaped like a backward facing tooth! I can attest that it works extremely well when run across thin sheet against a straight edge.

For cutting thin sheet accurately I sometimes also use a small cutting disc on a Dremel.....clamp the workpiece to a piece of plywood and make sure to use eye protection. This method is excellent when making small detail cuts in thin workpieces.

lastly, I cut thin discs for clock wheels by using a specially made trammel adjusted to the exact diameter,...this basically cuts thru the brass when revolved by means of a 'knife tool'. I sometimes use the same basic method on a square piece mounted on an arbour in the lathe to cut out wheels.

Finally (?!)...there is an Eclipse sheet saw which works very well,..it looks like a small panel saw but has a hacksaw blade built into the edge, thus allowing any depth of sheet to be cut.

Interestingly, I don't any longer use a scroll saw to cut thin brass as I did not like that method, although many people do use it quite successfully.

I’ve flattened bent sheet by annealing and then running it through a set of slip rolls - put a slight uniform curve in one way, then turn it over, reset the rolls a little and flatten it out on the second pass. Of course, it means knowing someone with the slip rolls, or spending more on another bit of equipment..

A simple bench shear will cut perfectly straight edges with no bending.

How hot should the brass plate be heated before flattening ?

Brass shouldn’t be worked hot in my experience. Some brasses are quite brittle at higher temperatures. Just anneal the brass normally (bring up to a dull red and then leave to cool).

Without knowing the volume required, the discussion is rather pointless.

If I wanted one or two, I would hack the sheet to something a little over-sized and mill it square and to size. If I wanted ‘several’ on an irregular basis, it may be more economical to sub-out the cutting. If I wanted a lot, a metal cutting guillotine would be installed if the requirement was on-going on a regular/routine basis.

Economy dictates the approach taken if it is a business enterprise. As a modeller, I expect the first approach is the most usual.

hello Brian

To straighten your brass sheets you might need to anneal (soften) them by heating to a dull redness, and allowing to cool. Then you could use a press to compress each sheet separately between two flat thick blocks of steel. A big vice might do to apply pressure if the pieces are fairly small. It really depends on how flat you need them, and the surface finish you are hoping for. Annealing to soften the sheets will (of course) reduce the stiffness and springiness, and reduce the shine. The length of time in a press is not significant - if nothing happens at once it won't help to leave it overnight.

Hope this helps

Cheers, Tim

Thanks for that info : yes, I have found that leaving it in the vice for a few days is pointless. I will try heating them to dull red hot tomorrow, then cooling and placing back in the vice.

NOTE : Some of the ebay companies are better than others at cutting brass and keeping it flat.

First the bad news : I tried heating a small piece of bent/buckled brass but it only made it worse and then when I tried to flatten it in the vice, it seemed even more springy. I am not sure what I did wrong there.

Now the good news : the small hobby table saw fitted with a fine tooth blade cut through the brass sheet like it was cardboard. I had my doubts when I bought it but it will prove to be extremely useful.

gQAAOSw1u9glNeg">Mini Multifunctional Table Saw Desktop Woodwork Household Saw DIY Cutting Tool 6973691950593 | eBay

Once I had cut the brass sheets then I straightened them out as best I could by hand. They should be okay to use now but I will look for a Chinese supplier who can cut them and keep them flat.

Edited By Brian John on 21/10/2021 12:53:40