Bending radius for small AL square tube

[Cynical]

Using a baileigh bender on 1" square tube (6063 for this home project), what is the ideal CLR to avoid distortion or crushing for this cosmetic application?

Baileigh says 4.25 and 4.5 CLR are the most common dies but they're out of stock for quite a while. "Most common" usually means for steel also.

Is 5" CLR a decent choice? What minimum wall thickness should I use to avoid or minimize crushing or distortion in the bend? No bend will exceed 90 degrees.

Thank you.

 

[EdT]

Somewhat of a non-answer, but go with the largest radius that your design can accommodate. For square tubing you could probably make an adequate die from some metal plates and some hardwood or MDF for the center piece if you are not planing to make a bunch. Annealing the outside and sides of the bend area might help or it might make things worse. I think it would help make all the metal movement outboard of the inner radius as "stretch" which avoids the tendency to collapse inward in the center of the radius. Basically, you're trying to move the bend line from the center line to the inside radius.I have had good luck bending smaller tubing by filling it with molten lead which I melt out after the bending. Might not be practical for what you are doing. I think the main issue will be the tendency of the sides to bulge out near the inside of the bend so keep an eye on that. It'll probably take a couple or three tried to get it to work or just use solid bar in the bend area.

 

[Cynical]

it will be a fairly tight radius, which is why I want to get as small as feasible without compromising aesthetics.

Like this application, just aluminum not steel.

https://m.imgur.com/kGxjG7D

 

[steel 35]

I Have used a 4" OD bearing with 3/8" plates outside and had nice 180* bends in 1" Aluminum. Did collapse inward As EdT said, Looked good to me

 

[Cynical]

Somewhat of a non-answer, but go with the largest radius that your design can accommodate. For square tubing you could probably make an adequate die from some metal plates and some hardwood or MDF for the center piece if you are not planing to make a bunch. Annealing the outside and sides of the bend area might help or it might make things worse. I think it would help make all the metal movement outboard of the inner radius as "stretch" which avoids the tendency to collapse inward in the center of the radius. Basically, you're trying to move the bend line from the center line to the inside radius.I have had good luck bending smaller tubing by filling it with molten lead which I melt out after the bending. Might not be practical for what you are doing. I think the main issue will be the tendency of the sides to bulge out near the inside of the bend so keep an eye on that. It'll probably take a couple or three tried to get it to work or just use solid bar in the bend area.

It's a purely hobbyist project, but assume money isn't the issue since I can use the die again at some point on a different project. I.e., I'll buy a die rather than make one, to hopefully get the best end product I can achieve. I will ask Baileigh Monday and hopefully get an honest answer (especially since they now own Rusch Machine & Design who makes the benders and dies), but I like the community input because it is unbiased. So...5" ya think?

Filling with lead might be more than I want to do, but I could fairly easily fill with sand and tack a cap on the end. That would probably avoid any crushing. The baileigh dies support the sides pretty well so that should alleviate the side bulge.

Thanks for your input!

 

[Cynical]

I Have used a 4" OD bearing with 3/8" plates outside and had nice 180* bends in 1" Aluminum. Did collapse inward As EdT said, Looked good to me

Great idea with the bearing. I could actually visualize making a square die using a bearing and plates with a bushing welded in to hold the bearing. Wouldn't work for round pipe or tube, but for square that's a possibility if I can't find what I need in stock anywhere.

It would be very similar to the OEM baileigh die if the plates were joined by threaded screws along the bend path (to make removal easier after bending).

 

[LXCam]

I bought a woodward tube bending kit from zoro a couple months back for two bills. It included a 1" square tubing shoe. I'd go that route.

Here ya go: https://www.zoro.com/woodward-fab-pipe-and-tube-bending-kit-steel-spbendkit/i/G6096045/

 

[Cynical]

Great idea with the bearing. I could actually visualize making a square die using a bearing and plates with a bushing welded in to hold the bearing. Wouldn't work for round pipe or tube, but for square that's a possibility if I can't find what I need in stock anywhere.

It would be very similar to the OEM baileigh die if the plates were joined by threaded screws along the bend path (to make removal easier after bending).

Eh, scratch that. The way baileigh dies attach to the draw pivot would require substantial machining on a different bottom plate, more than I could do in-house with any level of precision at this point. I'm sure it was designed that way to sell dies, and I don't blame them!

 

[Cynical]

I bought a woodward tube bending kit from zoro a couple months back for two bills. It included a 1" square tubing shoe. I'd go that route.

Here ya go: https://www.zoro.com/woodward-fab-pipe-and-tube-bending-kit-steel-spbendkit/i/G6096045/

What is the radius on the 1" square die, and did it crush like crazy with 16 gauge tube? Could be an option I guess.

I already have a bender and am committed to it with other dies, which is why I'm pretty certain to stay with the baileigh line. It's really a question of what radius for aluminum to avoid crushing.

 

[LXCam]

What is the radius on the 1" square die, and did it crush like crazy with 16 gauge tube? Could be an option I guess.

I already have a bender and am committed to it with other dies, which is why I'm pretty certain to stay with the baileigh line. It's really a question of what radius for aluminum to avoid crushing.

I'll check and get back to you on the radius, but if you got to woodwards site all the specs are listed. I haven't bent any square tubing yet so no help there. But honestly I don't think you'll have much luck with aluminum unless you get it annealed jusssst right. And that's after you get a couple different gauges to play with.

I know you have a good unit, but you yourself said you couldn't attain the shoe set so I tossed this out there verses cobbling something together. This unit is decently built. But the coating or casting work is terrible if you want a perfect finish. For what I bought the set to do which was 3/4" .092 tubing all that contamination transferred into the piece. So I took the 5/8" shoe and remachined it for a perfect finish. A bit of a PITA, but well worth the effort. Thankfully the square tubing dies would be an easy clean up unlike the round ones.

Here's the direct link but I lied to ya, the radius specs aren't listed but I will confirm for you.

https://www.woodwardfab.com/product/pipe-tube-bending-kit/

 

[EdT]

In the bend you are trying to do there is a lot of metal (about 3/8" on a 90 if I did the math right) on the inside of the bend that has to go someplace. It's either going to cave in or wrinkle no matter what kind of die you use if the bend is on the C/L of the tubing.The outside of the bend has to stretch the same amount.

 

[Cynical]

So what do you suggest is the best radius for aluminum bending? Anywhere between 3" and 6" are my options. 5" is available now, 4.25 and 4.5 will require a wait.

 

[EdT]

As I mentioned before, use the largest radius that your design will accommodate. Within that range of available radii, the amount of material you will have to absorb on the inside of the bend is similar. You probably should crunch through the arithmetic for yourself and see if you agree with my numbers. I've been known to screw up. It's pretty straight forward. For example, take the proposed CL radius, say, 5". Subtract 1/2 " from that which gives the radius of the inside of the bend; 4 1/2" in this case. The outside radius would be 5 1/2". Calculate the circumference of a circle 10" in diameter ( the C/L RADIUS =5) and divide it by 4 for a 90* bend. 10 x Pi/4= 7.85". Calculate the circumference of the inside 90* bend 9 x Pi/4=7.06". 7.85 - 7.06= .79". That (.79") is how much shorter the inside bend is than the C/L of the 90* bend. That is how much the metal on the inside of the bend will have to "shrink" to avoid caving in or wrinkling. A similar calculation for the outside of the bend will show that it will have to stretch about the same amount, but most metal stretches more easily than it shrinks. If you take the time to run the numbers for the various radii that you are considering, I think you'll find that they are pretty similar.

 

[steel 35]

My bends using the bearing. (Over the little drop wheels) 5" Centerline If its a U ?

View media item 10140

 

[ducksface]

Pack tubing with wet sand if you feel the need.
Just like said above but just plywood and sand. No lead.
(theres a special metal that melts below water boiling temp used for filling tube. $20 lb or so)

Look up
Kent Fuller.

With this project case the bender you have is a restriction on creativity.

 

[Cynical]

Pack tubing with wet sand if you feel the need.
Just like said above but just plywood and sand. No lead.
(theres a special metal that melts below water boiling temp used for filling tube. $20 lb or so)

Look up
Kent Fuller.

With this project case the bender you have is a restriction on creativity.

Yeah, you're right. I could use conduit and a hand bender and be ok on this case since structure doesn't matter. But, in fairness to me, I have other plans that will need to use 1" square tube and support a little more load than this vanity project. And I'm extremely uncreative.

Also, Steel35-- those bends using the bearing came out really nice. Well done.

 

[LXCam]

Hey bud the radius of that shoe is 3.5".

 

[racingtadpole]

Since it’s not structural, build your bends from sheet material at what ever radius you want.