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RussZHC
03-05-2015, 01:29 PM
Nearly all box and pan brakes give material gauge capacities for mild steel, some for aluminum as well.

Is there a rough percentage for stainless compared to the mild steel number? I am assuming it would be the lesser of the two. Or would you just go a gauge size or two thinner?

Thanks,
Russ

HWooldridge
03-05-2015, 02:21 PM
The 4 ft model that Northern Tool sells derates capacity at full width from 22 to 26 ga, mild steel vs. SS, respectively. The delta may be lower as the bend length decreases.

metalmagpie
03-05-2015, 03:53 PM
Just a note. You may know this already. A key spec for finger brakes is how deep a box they can bend. This isn't always obvious from catalogs.

metalmagpie

CCWKen
03-05-2015, 11:47 PM
Don't go by that Northern tool. A 22ga. mild steel capacity tool is pretty useless to begin with unless you're making duct work or tissue boxes. And stainless steel uses a different gauge standard than aluminum, brass and A36 steel. The strength difference between A36 and SS is substantial so you need to use the thickness rather than the gauge and cut the A36 thickness by about half. (Added: The actual number is closer to 48%)

For example: A brake that claims a capacity of 16ga. mild steel (CR 1008 or A36) means a thickness of .060". If you are bending SS, the capacity will be reduced by about half or .030". This is about a 22ga. in SS.

mixdenny
03-06-2015, 01:39 AM
The manual for the Chicago Dries and Krump brakes downrates them 4 gauges from mild steel to stainless steel. And they were built like tanks. Dennis

boslab
03-06-2015, 05:38 AM
I have a 4' Edwards folder, not even a finger or box machine, I found out how tough stainless is on it, it weighs about 3/4 ton and I was lifting the front of the machine with a peice 1.5 mm thick by about 18" long, ids all I could do to put a bend in it, I got there but only just!, tried shorter pieces, very hard work.
It takes a lot of muscle to shift stainless, I think a lighter machine might even break.
My final solution was gash bending, the gnashing being done with a thin slitting disk for stainless, iron free, and welding the corner.
Mark

Doozer
03-06-2015, 08:24 AM
Do steel mills hot roll sheets that thin??

-D

boslab
03-06-2015, 10:41 AM
Yes the mills I've worked on did, they could take it down to practically foil, but the mill had to work, drive currents would max out on wide, and rolls would get swapped out after half the time of mild steel, there would be a lip on the roll where the edge of the sheet was, pissed the roll shop off as a regrind takes time.
Mark

Prokop
03-06-2015, 11:09 AM
Ha, one more reason for USA to finally go metric :)

cameron
03-06-2015, 12:26 PM
Ha, one more reason for USA to finally go metric :)

I'm puzzled. Are you saying that the fact that you don't like to or can't read gauge specs is a reason for the U.S. to go metric?

Doozer
03-06-2015, 12:33 PM
The United States won every war they were in with a foreign nation.
I think the rest of the world should use our measurement system.
If we had lost a war or two, we might be speaking German today.
Why should we use a measurement system thought up by France?
-Doozer

Prokop
03-06-2015, 12:38 PM
I can read and work with both, but the USA system just makes very little sense especially gauges.

Look at the table here:

http://en.wikipedia.org/wiki/Sheet_metal

and compare it to thickness expressed in mm. Just a number and - imagine that if you can - you dont have to specify what material is the gauge for.

Revolutionary, isnt it?

DR
03-06-2015, 12:41 PM
In the Chicago press brake manual as a rule of thumb they say aluminum takes 1/3 the force of mild steel, SS takes 1-1/2 times the force. So, if a certain bend needs 1 ton force with mild steel, the same bend in SS will need 1.5 tons.

An important thing to keep in mind is most brakes won't do their rated maximum bends. My 24" Di Acro finger brake is rated full width bend in 16ga mild steel. Maybe on a good day if I had a helper. Even then, the bend won't be uniform across it's length.

With any brake it's probable a good idea to degrade it's advertised bending ability by at least one gage. If your bending work involves 16ga, get one rated for at least 14ga.

dian
03-06-2015, 12:42 PM
how does that gauge stuff work? 1mm is around 18 and 2 mm is around 12.

Prokop
03-06-2015, 12:43 PM
The United States won every war they were in with a foreign nation.
I think the rest of the world should use our measurement system.
If we had lost a war or two, we might be speaking German today.
Why should we use a measurement system thought up by France?
-Doozer

Using the same logic, maybe USA should speak and write Vietnamese, or did you win that war too?

cameron
03-06-2015, 01:18 PM
The United States won every war they were in with a foreign nation.
I think the rest of the world should use our measurement system.
If we had lost a war or two, we might be speaking German today.
Why should we use a measurement system thought up by France?
-Doozer

You forgot the war of 1812, Doozer. But of course, you're still using the Imperial system.

Except for your old Winchester gallon. They changed that after you guys opted out of the Empire.

mickeyf
03-06-2015, 01:32 PM
The United States won every war they were in with a foreign nation.
I think the rest of the world should use our measurement system.
If we had lost a war or two, we might be speaking German today.
Why should we use a measurement system thought up by France?
-Doozer

Ahem. Lookie (and listen) Here. (https://www.youtube.com/watch?v=WVC677-YmfM)

Paul Alciatore
03-06-2015, 02:37 PM
We didn't lose in Vietnam, we just quit.



Using the same logic, maybe USA should speak and write Vietnamese, or did you win that war too?

Paul Alciatore
03-06-2015, 02:44 PM
I have used one of the three-in-one sheet metal machines for a lot of work with aluminum, 0.032" and 0.040". It works well for that kind of work. Even did some SMALL parts with 0.062" aluminum.

And yes, duct type work with thin gauge steel. But you are not going to bend 0.062" thick steel with it. NO WAY unless it is only 1/8" wide.

I think that aluminum is where these light duty machines shine.




Don't go by that Northern tool. A 22ga. mild steel capacity tool is pretty useless to begin with unless you're making duct work or tissue boxes. And stainless steel uses a different gauge standard than aluminum, brass and A36 steel. The strength difference between A36 and SS is substantial so you need to use the thickness rather than the gauge and cut the A36 thickness by about half. (Added: The actual number is closer to 48%)

For example: A brake that claims a capacity of 16ga. mild steel (CR 1008 or A36) means a thickness of .060". If you are bending SS, the capacity will be reduced by about half or .030". This is about a 22ga. in SS.

boslab
03-06-2015, 02:47 PM
I'm sorry about this, SWG, aka standard wire guage's full name is british standard wire guage, I didn't like to mention it but mostly the American system isn't, it's a tad british, however I see no reason that it can't be still used if you like it, metric is probably where the world will end up weather we like it or not, primarily due to to fact the Chinese and Japanese use it and flood the world with 10 mm nuts and bolts
I worked for a Swiss company in Britain making some stuff for the Americans to be shipped all round, it was torture, imperial drawings, inc decimal and fractional measurements, converted to metric then back, mixtures of balls ups, parts not fitting, mad.
Mark
Before my ass gets torched I do know about all the other oddball sheet metal guage's too!