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How to bend 5/16" rod?

DavidR8

DavidR8

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I've been handed a project where I need to make maybe 30 U-shaped bends in 5/16" solid rod. The radius will be about 6 inches, with straight legs about 12"-14" long
I have a bench mounted ring roller and a floor mounted bender. Also have oxy/propane.
The stated capacity of the ring roller is 1/4" and the floor mounted bender is too small to make a 6" radius bend.
I was thinking of making a jig, basically a plate with some means to secure the stock while the free end is curved around.
Having never bent 5/16' rod I have no idea how much force might be needed.
IMG_8259.jpg
 
When I made battery hold downs, I used 5/16” stainless rod. To make the bent “foot” buddy of mine just put them in a vise and yanked on them by hand. I thought he might need to use a press. I’d think if you used a little heat and a short cheater pipe it will go easier than you think
 
It takes nothing to bend 5/16 round, you can defiantly do that large or a radius by hand easily, it will just take a few goes to figure out how much over bend it will take to maintain a 6" radius when you let off
 
I thought you said 6” RADIUS ?
6” Pipe even with heavy wall would only guide about 3-3/4” radius.

Use heavy 12” wall tube or a HD trailer rim as a forming guide.
As Ryan said, use a pipe extender to increase the torque production and use a sturdy, mounted forming guide. Trial and measure for over-bend.
 
LenVW said:
I thought you said 6” RADIUS ?
6” Pipe even with heavy wall would only guide about 3-3/4” radius.

Use heavy 12” wall tube or a HD trailer rim as a forming guide.
As Ryan said, use a pipe extender to increase the torque production and use a sturdy, mounted forming guide. Trial and measure for over-bend.
Click to expand...
Yup it's somewhere around a 6" radius, maybe a bit less. I need to measure the existing item (garden fencing) to be sure.
 
It'll definitely take a bit of experimentation to figure out the correct radius for the form, given the spring back. I was recently bending 3/8" rod. I needed a 31" radius, so made a ~25" radius form (essentially segments cut out of wooden planks on a band saw, brad nailed to a plywood sheet). The radius still ended up way too big because of the spring back, and I had to approximate the larger curve by making occasional tighter bends with a conduit bender.

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Looks good @Six O Two!
I might try one using my floor bender and see if I can basically coax it into the right radius a bit at a time.
Or is this an excuse to buy a bigger ring roller? :P
 
Thanks, @David_R8. I was definitely alternating between talking myself into and out of aquiring/fabri-cobbling a three wheel tubing roller... It's kind of stupid how many of my projects end up being side-tracked so I can make or get new tooling. This particular project is meant to be a table for getting my seedlings started indoors before the growing season, so it's about a month late as is, hence the need to make do with what was on hand... :D
 
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A 6" Class 150 pipe flange is 11" O.D. Has eight bolt holes. Bolt it to a chunk of plywood. Simple jig to put a fulcrum in the bolt holes to drag the rod around the outside of the flange. 11" O.D. is going to spring back pretty close to 12" c/l radius on 5/16" rod, and if it's too tight increase the flange o.d. with some small spacers of 1/4" aluminum bar.

6" Raised Face Slip-On A105N Carbon Steel 150# Welding Flange

www.flocor.ca www.flocor.ca

Scrap metal dealers end up with zillions of pipe flanges, they're worthless.
 
Thanks fo
whydontu said:
A 6" Class 150 pipe flange is 11" O.D. Has eight bolt holes. Bolt it to a chunk of plywood. Simple jig to put a fulcrum in the bolt holes to drag the rod around the outside of the flange. 11" O.D. is going to spring back pretty close to 12" c/l radius on 5/16" rod, and if it's too tight increase the flange o.d. with some small spacers of 1/4" aluminum bar.

6" Raised Face Slip-On A105N Carbon Steel 150# Welding Flange

www.flocor.ca www.flocor.ca

Scrap metal dealers end up with zillions of pipe flanges, they're worthless.
Click to expand...
Thanks for the idea, I'll see if I can find something like that locally.
 
+1 to the shaper method. The mystery shaper I picked up was being used to make bends by @johnnielsen at one time. Some of the jigs were still with the machine. John, do you know the thickness of rod?
 
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