Curving a Piece of Pipe for a Corral Project

[garybdavis]

I need to curve several pieces of 2 3/8 oilfield pipe for a cattle corral project. The radius will be 10' and 12'. I had a local guy roll several pieces for me into 20' diameter half circles and that will get part of what I need done, but it's not economical and scheduling him to do the work is a pain.

Anyway, I have this grand idea of buiding a press jig to bend the pieces in short sections and the weld them in place. These pieces would be about 8 to 9 feet long and need an arc of about a foot or so. I've already done the CAD work to know the exact dimensions and I have a log splitter with 30" stroke to use as my power plant for the hydraulic press. I'll custom make two press "dies" to get the two different arcs I need. I can make one frame with two different roller pins for the top half of the press frame.

The only thing I'm unsure of is how much spring back I'll have and how to compensate for it. The log splitter has a 5" diameter cylinder and with 2500PSI behind it, so I have plenty of power to work with.

Anyone ever done something like this before and have any words of wisdom for me?

Thanks

[Showdog75]

If you have a large and heavy enough welding table I'd lay out the shape you want and heat with a torch[rose bud] and pull with a come a long or such. I did this to a piece of 6" pipe at a old job. Much cheaper and faster than making dies. Once I layed out the radius I welded some large angle on the inside of the radius to form the pipe to. Also welded down one end to the table and started the bend from that end. It was really pretty easy.Get a helper so one can heat and the other to do the cranking on the come a long.

[Blondie_486]

You might also want to fill the tube with sand to avoid the possibility of crushing the pipe or kinking it.

[fdcmiami]

pipe

it's hard to believe that what you are proposing to undertake is going to be less costly than finding someone to roll them for you. your time is valuable also. i am aware that this is not always possible if you live away from a city.


that said you could get some 2 x 10's , screw them together. take a piece of plywood cut it so that it follows the arc and projects about one inch out. this will contain your pipe while you are bending it. lay out your larger radius first. somehow you are going to have to anchor this to something really solid. maybe get some expansion bolts and bolt it to a concrete floor. schedule forty pipe comes in 21's so i would anchor one end a foot or so before the beginning of my template and then attach the other end to a comealong and cold form it over the template. this will work, but life would be easier if you got some schedule ten.

[fdcmiami]

pipe

stacking two two by ten's will give you app three inches. lay out your pattern on them. largest first; i would layout a little tighter radius than required but it's going to be trial and error. then cut the two by tens to form the radius and then put the piece of plywood or whatever to retain the pipe during the bending process. try not to use any heat; the uneven deformation will be noticeable. you will also lose a lot of pipe because you are going to have to lay your finished product over the correct radius and choose the points that are going to give you the most accurate form; if tyou don't it will look like **** when you weld it together.

[fdcmiami]

pipe

couple of more points; you can make your radius tighter to allow for spring back. it is fairly easy to open something up that has been rolled or formed as opposed to cutting your template several times. i used to layout cam shaped templates so that i could work my metal as i was bending it and checking it against my template.

also, i said to lay out the larger radius first so that you can use your wood again to for the tighter radius on the second set of bends.

[Showdog75]

stacking two two by ten's will give you app three inches. lay out your pattern on them. largest first; i would layout a little tighter radius than required but it's going to be trial and error. then cut the two by tens to form the radius and then put the piece of plywood or whatever to retain the pipe during the bending process. try not to use any heat; the uneven deformation will be noticeable. you will also lose a lot of pipe because you are going to have to lay your finished product over the correct radius and choose the points that are going to give you the most accurate form; if tyou don't it will look like **** when you weld it together.

Why not use heat ? Makes it ALOT easier to bend. I'm speaking from experiance.It wont deform if you heat evenly. If your worried about deformation fill with sand as blondie said. Also if you form it to a radius you shouldn't have to choose your points and waste pipe , I never had to waste any.I'd have gotten run off for wasting unneccesary material.

[fdcmiami]

pipe

i have formed, hot and cold, a lot of steel and aluminum. heat for bending is always localized. i am calculating, using a chord length of ten feet that would make the included angle between the chord app sixty degrees. pi x d is equal to about sixty three feet. i am working to inside numbers here; custormarily i would be calculating to the mean diameter of the pipe in circumference.

using these numbers i am estimating the rise from the chord to the underside of the arc at app sixteen inches. this should be not to difficult to bend. if you are locked into the sch forty go for it, but if you can order some sch ten.

if you rolled semi circles to 20 feet in diameter you had something other than a twenty foot diameter as it would take three lengths of 21 foot sch forty to make the correct diameter. again pi x d.

[fdcmiami]

two further points

1. we are talking about bending a schedule forty pipe to a radius of 120 inches. elevation from c/l of chord, app 16 inches. this is not a tight bend. therefore we will not be needing any sand. sch forty pipe has app a 5/32 wall. beefy enough to not need any sand.

2. this whole excercise is about deformation of the steel pipe to get to the specified radius. bending IS deformation. as to wasting pipe it depends on what kind of product you want to put out. as i said earlier. i have done a lot of this. pipe is cheap.

[Bodybagger]

I need to curve several pieces of 2 3/8 oilfield pipe...

...The only thing I'm unsure of is how much spring back I'll have and how to compensate for it...

2" pipe is all 2.38" OD whether it is standard, extra strong, or double extra strong.

Without knowing which cross section and grade of pipe, estimating spring back is impossible.

Accurately predicting springback is a little more difficult. You generally need to run a bending process on a uniform batch of material and measure springback angle for several runs, then use statistical analysis to determine the spread. Material properties generally exceed their specifications and do vary a good bit from batch to batch. Therefore, test runs are the only way to really even get close to the actual quantity you are looking for.

http://www.thefabricator.com/hydrofo...le.cfm?ID=1607

Sure, you can whip up a bending die for a log splitter in a fast hurry, but in the time you spent correcting things it can't do well, you could have made a roll bender.

If you MUST do it yourself, make a roll bender. Just scale up the HF model big enough (and strong enough) to do 2" pipe. You'll need some elbow grease to run it though.

[fdcmiami]

pipe

of course two inch pipe, is two inch pipe regardless of the sch. it is the wall thickness that counts here. the 2 3/8 in od is irrelevant. i suggested a sch. 10 because it would be more easily formed. the excerpt printed above was probably written by an engineer. you have solved nothing for the poster that requested the feedback, you are suggesting rebuilding a HF machine (an oxymoron), and then he will still have to run a bunch of test pieces through to ascertain his springback; i am suggesting bolting the wood to the floor, cut the radius to a smaller size; you will have to do some handworking but you won't have to buy and rebuild a machine and you will not have to roll a bundle of pipe to get what you need. again, this is a large enough radius to cold work the pipe.

statistical analysis?
batch run to ascertain material properties?

if everyone that wanted to bend some metal went to all that trouble nothing would get done.

as long as it is not sch 80 pipe he should not have too much trouble

this pipe is being formed to build a corral if i'm not mistaken.

[garybdavis]

I've got 8 curved sections in this corral. At four railings per section, that's 32 pieces of pipe to bend. That's why I was thinking of making a jig for a hydraulic press. It would be very time consuming to do it with a come-a-long and rosebud. Plus, I'd have the jig for making more if I decide to expand the coral or build another one.

[Black Wolf]

Sweet Freakin' Marie.....

Gary is bending some Oilfield tubing for a corral....

You guys are treating it like he is building the bloody space shuttle....

This is not nearly as difficult or as scientific as you two are making it.

If it were me Gary, I would either bend it around a form similiar to what Showdog proposed, OR whip up a couple of dies (that you mentioned) and use your log splitter like a BIG pipe bender.

Once you are set up, the log splitter should be easier...

Start with shallow bends evenly along the joint of the pipe, then go over it again, and bend it a little deeper to "tighten" up the radius, until you have what you need.

Mathmatics have their place - but all this calculations mumbo jumbo isn't getting anything done, and time IS money.

My apologies to the members whose feathers I have ruffled... Realize that my post is merely one man's opinion... I just think you two are making a mountain out of a mole hill.

If every job in industry was approached your way - NOTHING would get done.

[JSFAB]

This might give you some ideas, but it's more of an art than a science using something like this.

I built this for cold forming 1045 wearplates to fit the bottom of excavator, backhoe, and loader buckets, with a little modification (maybe some basic dies to help prevent collapsing the pipe) something like this would probably work for your situation, also?

[Black Wolf]

Great Picture JSFab...

THAT is basically what we call a "Pipe Bender" up here, and what I pictured Gary doing with his log splitter.

Perfect timing.