Sheet Metal Brake

a fine line between stupid and clever

Sheet Metal Brake

Postby Hotsauce » Wed Apr 20, 2011 7:20 pm

Anyone have a brake that can handle .125" engravers brass sheet?

I need 4 bends for a chassis shape

I can either pay, or trade tubes.

John C.
User avatar
Hotsauce
 
Posts: 88
Joined: Sun Sep 21, 2008 5:56 pm
Location: Bronxville

Postby burnedfingers » Tue May 24, 2011 4:44 am

Do you have a metal shop in your area? Bending metal of 1/8" in a hand brake would require a hefty brake. Most hand brakes are limited to 16ga usually. Sure you could probably bend it but it might spring the shoes.
burnedfingers
KT88
 
Posts: 640
Joined: Mon Sep 05, 2005 6:38 am

Postby Geek » Tue May 24, 2011 3:57 pm

Brakes for that thickness are big hydraulic things. Not even the $1000 pan brake I'm eyeing can do that. A local steel shop here does custom bends on lunch hour. Might want to check out a local steel shop.

Cheers!
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3585
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia

Postby burnedfingers » Wed May 25, 2011 5:04 am

Spent a few years running both hand brakes, hydraulic, and for the lack of a better term mechanical brakes. I have run some smaller mechanical brakes that will bend 1/8 steel with ease. To build a chassis one must consider that the material will have to be notched for the corner bends prior to making the brakes. Consideration will have to be given to the size of the bottom die also. Your not going to be able to make the brake with a 1/8, 1/4, or 3/8" bottom. A 1/2 bottom die would probably be pushing things. A 5/8" or 3/4" bottom die is probably what would have to be used.
If I were to brake a piece for a chassis I would consider two brakes per side for a total of 8 brakes. This would give a bottom lip in which a bottom plate could be attached.

One could complicate things even more if you considered the tube socket placement, transformers, controls mounting holes for the mentioned devices as well as mounting holes for the bottom plate.

So, prior to any other work you would have to plan the holes needed and have them punched on a punch press. Clearance for the bends would dictate notching for the corners prior to braking. Lastly the braking but this would be after braking a piece of known length same material and figuring an allowance for the brakes. Material can be gained or lossed in braking and this is a factor of the bottom die size, top die used and hardness of the material just to name a few.
burnedfingers
KT88
 
Posts: 640
Joined: Mon Sep 05, 2005 6:38 am

Postby nyazzip » Thu May 26, 2011 2:49 pm

brass is brittle hard stuff. i would be surprised if you could get a 90 degree bend in it without it cracking, unless you anneal it somehow, no....?
<i>the poor craftsman blames his tools</i>
User avatar
nyazzip
KT88
 
Posts: 1073
Joined: Wed Jan 09, 2008 1:24 am

Postby Geek » Thu May 26, 2011 5:18 pm

High zinc or "yellow" brass is pretty bendy stuff.

I used to make chassis from kickplate brass that was really high zinc content before they cheaped out and "brass coloured" zinc slag crapola and increased the price by a factor of ten =:o

Cheers!
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3585
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia

Postby Hotsauce » Fri May 27, 2011 1:06 pm

The brass I use is what we call '85 and 3 5's'

85% copper, 5% each lead, tin, zinc. The lead makes it free machining. This is not garbage like half hard stock.

In any case, I have decided to piece this chassis together.

.125" C101 copper sheet, 2x.125 brass angle.

Its going in a wooden chassis afterwards and won't need sides or bottom.

Image

John C.
User avatar
Hotsauce
 
Posts: 88
Joined: Sun Sep 21, 2008 5:56 pm
Location: Bronxville

Postby burnedfingers » Fri May 27, 2011 5:03 pm

brass is brittle hard stuff. i would be surprised if you could get a 90 degree bend in it without it cracking, unless you anneal it somehow, no....?


It will bend fine as long as the bottom die selection is correct. Too small a bottom die will promote cracking. The same thing goes for aluminum.
burnedfingers
KT88
 
Posts: 640
Joined: Mon Sep 05, 2005 6:38 am

Postby ramkumar » Sun Jul 10, 2011 8:23 am

I think reply for 6bg6ga has got weight, he has got logic behind his words.
ramkumar
 


Return to guitar amps

Who is online

Users browsing this forum: No registered users and 10 guests