Bending suggestions needed!!

[Tacker Beau]

Hi folks, To start I must say, I've spent many a Sunday morn., with coffee in hand, pouring through these threads, and have learned alot! This is quite the interesting hobby!
My question this day, is about bending steel. I've picked myself up a small bender, the bench mount type, just for small stuff, and to get the hand of all this.? I just can't seem to get the lenghts right. Example: If I bend a two inch rad., with, say 24" to one side and, a bunch of material to the other side.
How do I measure the placement of the next rad., of the same size, to get another 24", inside or out of this U shape that has appeared. I always seem to be short or long.
I hope I've made this understandable? There has been many a knot in my forehead some days.
I also read here somewhere, there is a formula for the bearing weight of steel, such in the case of railings. (lenght x steel thickness = no sagging?)
Thanks, T.B.

[aametalmaster]

And i will be the first person to say i messed up some pcs trying to get a perfect part but i have learned to fudge it a little. I have an HF bender also. What i do is mentally divide the 2" roller into 90 degree segments. So you know that die is going to move say 1 1/4" or so with the metal for a 90 degree bend. The metal moves with the die as the die rotates so just picture it as one. So maybe mark segments on the tops of your dies and then use a tape measure to see how far you need to move the metal for the bends and where the bend is finally going to end up. And start a bucket in the corner for the screw ups you can use them on other projects...Bob

[HillbillyFAB]

This may or may not help. I bend on a JD2. I've got a spot on each die marked with a grinder, marked where the bend STARTS. This helps me when laying out, building steel to fit certain specs. Hope that makes sense.

[davedarragh]

Bending Pipe

Tacker: Welcome to the Forum. "A fountain of knowledge." Did you not get a book, or a guide with your bender?

When bending EMT, there's what's known as a "pick up" you have to allow for. 1/2" EMT allow 5", or if you need an 11" stub, set the bender head arrow at 6" and you have a 5" radius. 3/4" allow 6" , 1" allow 8" so forth and so on. Math is math, doesn't matter what material you are bending, but yes, there is a definite formula for figuring radius' and tube length. Hope one came with your bender.

Hope this helps

Dave

[chrisgay@sbcglo]

With the style of bender that you have, it is very difficult to get exact repeatablility. As Dave mentioned, there are charts and manuals, which essentially come down to understanding the math, which is not that difficult. You really just need to know where you bends are beginning and how much you are going to lose in the bend. Like Hillbilly says, this often just requires some monkeying around, marking your dies and/or pieces and keeping records. You just need to become familiar with your machine. Often, I will create oversized pieces and trim them to length after the bends are made.

I find it is essential to clamp the material to reduce/eliminate slipping, as many times the material will want to slip/pull throught the die as it bends. This leads to inconsistency and you will really be getting upset by days end.

As Bob says, be prepared to have a pile of scrap for the mistakes. We all have them and this is how we learn.

[aametalmaster]

As Bob says, be prepared to have a pile of scrap for the mistakes. We all have them and this is how we learn.

One other thing is i cut a known length of steel say 30" long and make some bends. Now you know how far you stayed in from the ends just use it for a guide and add or subtract to get the distance. You can make lots of parts that way. I do it like that when making scrolls. Because the metal in the ends doesn't change just the length between them does...Bob

[davedarragh]

Pipe Bends

Tacker: I think I found the formula in one of my many books.

L= R x D x .01745

L is the length of the bend

R is the radius of the bend

D is the number of degrees of the Bend

If the length of the entire pipe is desired, the length of the tangents must be added to the length of the bend.

T= tangent

I'll look up some more data tomorrow.

Dave

[FusionKing]

You can do all the math you want but I prefer the pattern method...it is fast and accurate.
What I have gone to now on my JD2 is right along with Hillbilly()....
make some patterns up out of the material type you are using such as a 90 and 45 degree parts. Short ones that are marked or painted so you won't throw them away and can find them when you need to. Now on those you need to measure back fron where the die actually digs in bending and make a line on the pattern at the EDGE of the die when the part is being bent. That line is the key to transferring over to your work so make SURE you don't wipe or wear it off.
Make your first bend and then lay the pattern over the piece you are bending and transfer your mark to it where you want the second bend and bend it. Once you get it figured out you will be able to make perfect results over and over.
It's a little more involved than that but basically that is what it amounts to. Different dies will have different spots they actually begin bending, so you need at least one pattern for each die to arrive at this, which you will need to know anyways to do the math method as well. If you didn't and was say 1/8th" off, after a few bends, you will create junk.
Once you learn this you can teach anybody with a little sense to use a bender quite well. And they don't need to be a math wizard.

[Tacker Beau]

Wow! I just spent about a half hour, hunting and pecking on this key board, Thanking everyone, and poof! Had to relog in.
In short, the bender I bought was on the cheap side, so no real instructions came with it, other than how to set it up and bend letters, U bolts and such! Got what I paid for!
I am going to try the math stuff, and spent some time getting to know this thing, by marking the dies and watching the process more carefully, but I really like the idea of the patterns. This seems the simplest.
I've made some nice bends with it, out of various lenghts of material, and then cut the ends to match the application,welded in. The end result just didn't look as proffessional as I would have liked, but did do the trick!
Thanks for all of your suggestions! I'm off to fill my recycle pail!?( hopefully no knot in the forehead) Tacker

[ligito]

I use a Diacro 1A. They have a manual that can be downloaded, called "The art of bending".

It might help.

I have a spare Diacro 1A, if someone needs to buy one.

[Johnny]

I bend some rigid copper now and then to make garden hose hangers, trellis' and arbors.

Take the final angle divide by 2 and use that angle as the center of the bend. I hope I am talking about what you asked about.

What I recently thought, after a long time away from bending, was the correct way to align the piece and get the center of the bend at a certain distance for a 45deg bend.


The center of the bend is off considerably.


The correct centering for a 45deg bend is at the 22.5 degree mark


This is reasonably well centered.

[TS-Off-Road]

The best software available for tube bending.

http://www.bend-tech.com/

[Bodybagger]

I also read here somewhere, there is a formula for the bearing weight of steel, such in the case of railings. (lenght x steel thickness = no sagging?)
Thanks, T.B.

Every span sags. There is no way around it. The sag of a uniformly loaded beam supported only on rollers is

delta=(5*w*L^4)/(385*E*I) Where

delta=sag at mid-span in inches
w=uniform load in pounds per linear foot
L=unsupported length in inches
E=Modulus of elasticity in psi (29,000,000 psi for steel)
I=section moment of inertia, in^4

The only ways you can get rid of sag are:
1: to roll a crown into the beam equal to the deflection
2: fully support the beam so that w=0

Now practically speaking, deflection can be small enough to be very hard to detect.

[thunder71]

do it this way & it will be perfect over & over again>>>>>>>>>>>>>>>>>>>>>

You can do all the math you want but I prefer the pattern method...it is fast and accurate.
What I have gone to now on my JD2 is right along with Hillbilly()....
make some patterns up out of the material type you are using such as a 90 and 45 degree parts. Short ones that are marked or painted so you won't throw them away and can find them when you need to. Now on those you need to measure back fron where the die actually digs in bending and make a line on the pattern at the EDGE of the die when the part is being bent. That line is the key to transferring over to your work so make SURE you don't wipe or wear it off.
Make your first bend and then lay the pattern over the piece you are bending and transfer your mark to it where you want the second bend and bend it. Once you get it figured out you will be able to make perfect results over and over.
It's a little more involved than that but basically that is what it amounts to. Different dies will have different spots they actually begin bending, so you need at least one pattern for each die to arrive at this, which you will need to know anyways to do the math method as well. If you didn't and was say 1/8th" off, after a few bends, you will create junk.
Once you learn this you can teach anybody with a little sense to use a bender quite well. And they don't need to be a math wizard.

[HillbillyFAB]

The best software available for tube bending.

http://www.bend-tech.com/

I agree on the bendtech. I don't own it, but played around on it at a friend's shop tht does.
Here's a link Tin Bender put up, that really drove home the principles when I was first starting out.

http://www.pirate4x4.com/tech/bendin_tube/index.html