Forming Aluminum Flanges (Bending Hoops)

I need a recommendation for a manual machine to form circular flanges that will be welded to the outer circumference of aluminum pipe. The specs on the flanges are:
Material: 6061 Aluminum
ID of flange: 28 inch
Stock: rectangular bar 1 by 3/4 inch
Bending on: 3/4 inch side

I was imagining something like a very short but beefy 3 roll slip roller, but I don't recall ever seeing something exactly like that.

I'd sure appreciate a suggestion.

Thanks very much!
Dave

LowEnergyParticle said:

Bending on: 3/4 inch side

Click to expand...

Uhh, both sides bend.

Is the thinner part of the bar on the OD, or the ID?

T.J. Snow IIRC makes the butt flash welder, and last I talked with them, they could also
provide the rolling machine.

bosleyjr said:

Uhh, both sides bend.

Is the thinner part of the bar on the OD, or the ID?

Click to expand...

My bad. The "hoop" that gets formed from the 1" by 3/4" bar stock ends up looking like a very short piece of large diameter pipe: the pipe is 1" long, has a wall thickness of 3/4", and the ID is 28".

Thanks for looking at this!
Dave

LowEnergyParticle said:

My bad. The "hoop" that gets formed from the 1" by 3/4" bar stock ends up looking like a very short piece of large diameter pipe: the pipe is 1" long, has a wall thickness of 3/4", and the ID is 28".

Thanks for looking at this!
Dave

Click to expand...

In ring rolling parlance that's know as the "Easy way" doing it the other way would be "Edgewise" bending
AKA the "hard way".

For a one-off, you could do it incrementally on a press brake. See Tom Lipton's book "Metalworking Sink or Swim".

If you only need a few, and they are often different sizes, I bend that on the hossfeld, manually. I have bent literally thousands of rings on the the hossfeld, ranging from 1/8" round to 1 1/2", flat bar and square.
If you need a lot, you arent gonna roll 3/4" thick material, even aluminum, on a hand crank slip roll- you need power. Most of the manual 3 roll machines top out at about 1/2" round. You are not going to find a manual machine that will roll 1" x 3/4".

Cheapest new machines are the little 3 roll machines like this one.
http://www.eaglebendingmachines.com/cp3008RAY33.html

I use a bigger version a lot, and it will do this easily. Rolling, though, is a bit of a black art, in that, there is no setting for 28" circle- you need to roll a few, trial and error, and figure out what your height setting needs to be for repeatability. The newer rolls have digital height readouts, but they are not in reference to any absolute- they are just for repeatability.

Photo is of 1 1/4" stainless solid round being bent into about a 24" circle. This material was heavily forge textured first.


there is this Baleigh- but I am frankly dubious about it rolling 3/4". But its as cheap as you are gonna find.
Manual Roll Bender (R-M1) | Baileigh Industrial | Baileigh Industrial

Ries,
if needing several, wouldn't it be better to make a spiral, and then cut it into pieces ?

You'd get rid of the flats on the ends of the rings that way too.

depends on the material, and the rolls.
I often pull spirals in round bar, especially in smaller sizes.
On 3 roll machines, the thickness of the dies can be a factor, as well as the length material comes in.
Alumnium and Stainless both come in 12' lengths.
Means that the biggest circle you can roll from one piece is about 4' diameter.
And that if you are rolling a spiral, to get two from a 12 footer, you must be rolling no longer than 22" to get 2 from one length.
Lot of waste in circles.
Sometimes I actually weld up multiple parts, but its best to do that after rolling, not before, as, no matter how much you bevel and how good your penetration, they tend to crack and break at the welds while you are rolling.