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Building home made pan/box brake

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TomTom1

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Nov 23, 2012, 10:28:09 PM11/23/12
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Any one have any diagrams? I am attempting to build a pan brake to bend
1/8 sheet metal up to 36 inches wide manuelly. Using 4 x 7.3 channel
iron and 1/4 x 4 angle. Will use 1/2 x 3 F.B. where needed. Thanks.




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TomTom1

Steve W.

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Nov 24, 2012, 12:42:41 PM11/24/12
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1/8" X 36" is going to take you a LOT more than the materials you
listed, and 36" bend in 8 gauge is going to be virtually impossible with
a manual unit. I don't know of a commercial manual that goes much over
12 gauge.

A 60 ton press brake with proper dies can do it.

--
Steve W.

Larry Jaques

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Nov 24, 2012, 12:51:31 PM11/24/12
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On Sat, 24 Nov 2012 03:28:09 +0000, TomTom1
<TomTom1...@diybanter.com> wrote:

>
>Any one have any diagrams? I am attempting to build a pan brake to bend
>1/8 sheet metal up to 36 inches wide manuelly. Using 4 x 7.3 channel

Manuel, he ees not heere.


>iron and 1/4 x 4 angle. Will use 1/2 x 3 F.B. where needed. Thanks.

Google is your friend:

http://www.google.com/search?q=bending+1%2F8+steel+plate

--
Good ideas alter the power balance in relationships, that is why
good ideas are always initially resisted. Good ideas come with a
heavy burden. Which is why so few people have them. So few people
can handle it.
-- Hugh Macleod

Jon Elson

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Nov 25, 2012, 12:41:40 AM11/25/12
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I have a light-weight Chicago finger brake. I use it mostly
to bend .062" aluminum, and it can just handle that OK.
The brake beam on top is a solid steel 2x4 with some braces
welded to it. The platen (main frame) is equally solid, and
the folding plate is a huge piece of 3/8 and 1/2" steel.

Remember, this just handles 1/16" aluminum! You want to bend
1/8" steel? You need a brake that weighs something like 2000
Lbs, and is probably hydraulically operated.

A press brake seems to be the modern tool for this kind of work.

Jon

TomTom1

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Nov 25, 2012, 2:03:06 AM11/25/12
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'Steve W.[_4_ Wrote:
> ;2965798']TomTom1 wrote:-
> Any one have any diagrams? I am attempting to build a pan brake to
> bend
> 1/8 sheet metal up to 36 inches wide manuelly. Using 4 x 7.3 channel
> iron and 1/4 x 4 angle. Will use 1/2 x 3 F.B. where needed. Thanks.
> -
>
> 1/8" X 36" is going to take you a LOT more than the materials you
> listed, and 36" bend in 8 gauge is going to be virtually impossible with
>
> a manual unit. I don't know of a commercial manual that goes much over
> 12 gauge.
>
> A 60 ton press brake with proper dies can do it.
>
> --
> Steve W.

I have a 50 ton press which is 25 inches wide and it will bend 1/4 plate
with ease. It only takes 4 tons pressure to bend 1/8 (12 guage plate) I
dont want to rebuild my press to accomodate the 36 inch width. Rather
rebuild an entire new set up. And yes, 2 men on a 48 inch 12 guage box
brake can bend a 36 inch wide piece of 12 guage. :)




--
TomTom1

Carl Ijames

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Nov 25, 2012, 9:54:41 AM11/25/12
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Just some doodling with numbers by a non-engineer :-). Using your number of
4 tons (8000 lbs.) to bend a 25" wide piece, then it will take 36/25 * 8000
lbs. = 11520 lbs. to bend a 36" wide piece of 1/8" steel. With your 4x7.3
channel mounted vertically so the force is applied to one of the 1.7" wide
flanges (in line with the 4" face so the flange itself won't bend), and the
ends rigidly supported by your design, a force of 11520 lbs. uniformly
distributed will result in a maximum deflection of 0.010". If the ends are
simply supported (so they can rotate as the beam deflects) the deflection
jumps to 0.053" so reinforcing those ends and making your hinge arrangement
as stiff as possible is mandatory. As for 1/4 x 4" angle for the rotating
part, it is only 64% as stiff as the C channel so it will deflect 1.56 times
as much (so 0.016" if rigidly supported which will be difficult and still
allow motion, and 0.083" if simply supported at the ends). All of these
deflections are directly proportional to the load force and inversely
proportional to the moment of inertia of the beams, so browse a table of
channel and angle properties that includes the moment of inertia and see if
there is a size you can step up to that makes sense (I used 4.59 for the
channel and 2.936 for the angle for moment of inertia).

-----
Regards,
Carl Ijames
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