bending pipe

[FieryFurnace]

I've got a friend I am trying to help out on a project.

What it is, is some 5/8" OD schedual 40 steel pipe. They need to be bent in a U-shape with a 4-6 inch radius. I don't have any experience working pipe cold or hot. He has tried bending the pieces cold but they collapse.

So for the questions?

What would be a good but simply jig that could be built to bend these with?

Would you recommend bending them cold or hot?

Thanks!

[781]

Cold bending dies for a hydralic press the pipe is suported on the outside in a female die and bent with a sliding male die.

If bending with out ouside support you have to fill the pipe with dry sand and close the ends mechanically to keep it from colapsing

If using heet make sure the sand is dry or it will make steam and could rupture which would be very dangerous

[Fosterob]

Sand inside the pipe is a good way to go but it must be DRY, lay it in the sun in a thin layer to dry. Also do not refer to PIPE as being 5/8 od call it by its pipe size, without looking it up I would guess you have 1/4" schedule 40 black pipe. When you mention the OD that is referring to TUBING, which is measured by the outside diameter. Most people are easily confused on this, and it is important to not get pipe and tubing mixed up even though they are almost the same thing.By calling them their proper names gives you more credibility as well. Hope this is helpful for you.
Rob

[clinton]

That sounds like a pretty tight radius even for the small pipe, a hossfield bender will do it cold- look at this link that shows how you can do this by hand with a big enough cheater bar
http://www.hossfeldbender.com/tooling/basic-pipe-eye-bolts-rings.php#2

[jimmy seale]

sounds to me like 3/8" pipe...be sure to use black pipe if you heat it not the galvie water pipe.

[David Einhorn]

In a past conversation with the sales dept at Durrett Sheppard I was lectured that Durrett Sheppard differentiates between pressure- tested product as "pipe" and the same product that has not been pressure tested as "tubing". On the other hand when talking to the local steel yard they call their untested product "pipe". In my humble experience, when talking to each respective company, the experience is one of condescension if the company's preferred terminology is not used.

[Fosterob]

Yes 3/8" not 1/4", it was late last night... Thanks Jimmy
Tube,pipe,The difference is how the size is called out. Pipe sizes are standardized so that the threaded fittings will work when the pipe end is threaded to fit the fittings. Pipe is not usually interchangeable with tubing due to its odd outside dia. As I said most people are confused here.
Rob

[FieryFurnace]

Yep it's confusing! LOL Thanks for explaining it, though I probably won't remeber it! It's sort of like trying to remember that when you brake metal you are actually bending it! Who came up with that one???

Ok so we are dealing with PIPE not TUBING! Got it.....for now!

Check out this link. What do you think about using a jig like this and bending hot filled with sand? It seems like the V-pulleys would support the pipe similar to the male and female dies on the benders. Thoughts???

[HWHII]

You can also make a die using flat bar, say for what you doing 3/16" x 1 1/2"" bent the easy way then take some 3/8" or solid round stock bend it to weld on the top and bottom of your flat bar to capture the pipe about 1/3 of the dia. Tack that to a plate or bench. Then bend it like in the picture you posted

[Fosterob]

You did not say how many pieces need to be bent. Heat and sand would be good for a few but a bending jig to support the pipe cold for larger quantities. All you need to bend it with sand is something round of the proper size to wrap it around, the sand inside gives all the support needed. That small size you might be able to do cold with the sand packed in it.
Rob

[macbruce]

I would say Quantity is a big factor in how strung out you decide get on making bending dies, for a couple of pieces sand would probably do........If you have allot you should forget about sand.
The prefered method in the photo is done primarily with a machined die (in ctr of the diacro, hossfield etc)and will usually do the pipe in one sweep without distorting the sides, cold.....The machined die doesn't have to be in a bending tool to work, you simply pull the pipe round by hand......hot I would reckon
A simple thing to fab shown in the drawing is a jury rigged version of the machined die made of round pieces. It will work but is more hassle cause the expanding sides of the pipe will pinch, when you feel that happening you need to slip it out and tap the swell into shape before you resume bending.........mb

[Steve Sells]

I would use my conduit bender. but that just me...

[macbruce]

I would use my conduit bender. but that just me...

Too simple............


HOW MANY....................???

[HWHII]

Dave, Here are a couple of photos of a die I made for SCH 40 1/4" pipe 3" radius center line. I use a torch heat and bend as I go around.

[macbruce]

Dave, Here are a couple of photos of a die I made for SCH 40 1/4" pipe 3" radius center line. I use a torch heat and bend as I go around.

Hw, Do your dies eliminate side swelling and kinking ? If so I'll be fabing mine that way in the future......Looks as though your design could be workable in my diacro............thanks.......mb

[HWHII]

Hw, Do your dies eliminate side swelling and kinking ? If so I'll be fabing mine that way in the future......Looks as though your design could be workable in my diacro............thanks.......mb

The round stock helps. You do not get any kinking maybe a little side swelling but it is hardly notice it. A friend showed me how to make this type of die. He uses them on alot on special type bends. He uses them in a hossfeld with a standard rolling pipe die that mounts on the swing arm. With that set up you get a excellent bend. This die I made before I got my hossfeld. Now I would make them to mount in it.

[nuge]

Man if you get a minute I would like to see how you rig that up in the hossfeld. Thanks.

[FieryFurnace]

Thanks for all of the replies, info, and help. I think HW may have just the thing. I'm not sure right off how many my friend needs done....maybe a dozen or more.

[KY Metro]

Hello all,

I am Dave's friend with the pipe, and this is my first post here. Dave, it was very kind of you to start this thread for me.

I have been lurking a bit but now I have to present my case. I am a bit puzzled on how to bend the pipe. As Dave said, it is nominal 3/8" iron pipe, which means it is closer to 1/2" I.D and 5/8" O.D. There are seven pieces, each three feet long. Pretty thick walls on this pipe, it fits in a conduit bender, but I would need to hire a gorilla to bend it that way. I need to make a very tight U bend, 4-6 inches diameter (not radius). It seems hard to believe, but it has been done before by a fellow with a very similar project, on the Forestry Forum. He built a gasifier to power a truck on wood chips, which is what I am trying to do. I may post a thread on that at some point, if you want to hear about it.

I asked Dave about this problem last week. I was curious if there were any special blacksmith tricks for bending pipe, or if it bent easier/more accurately while hot. Thus avoiding the die problem. He didn't know, and offered to post the question here. Which he has done. I surmise from the responses that there is no "secret" to pipe bending, just try to distribute the pressure over as much surface area as possible to prevent kinking.

I have talked to a couple local machinists, who told me that the proper tool is a pipe bender, which they had, but they didn't have the right size pipe die (5/8" OD). Nobody sells a 5/8" die. So I am sort of on my own there.

Since I have brought up the problem, several homemade jigs have turned up, in this thread and elsewhere. I should be able to build one, I just have to pick a design and get cracking. It looks like the hard part is the die; I have done a bit of metalcasting in the past and I may be able to cast a die in aluminum. I have seven pipes to bend, that shoots the one-off methods (sand-filled pipe, etc.) If I build something interesting I will post the updates here and on my blog, eatmorechili.bogspot.com.

Thanks for all the support.

Ky Metro

[JNewman]

Hossfeld catologue Look on page 10. I bend 3/4" pipe (just over 1" od) regularly to a 3" radius cold by hand using a Hossfeld. It does take a 10' handle but 3/8" pipe would be easy. The die won't be cheap I am guessing $250-350 but it will do the job easily.

I have been told of using a 1/2 section of pipe to fabricate a pipe bending die for a smaller diameter pipe but have not tried it. You could bend the larger pipe using the sand method, cut and grind the outside half of the pipe away and weld in a center.

[JNewman]

You won't be able to bend the pipe in a 180 degree bend using the pipe bender you posted a link to. Think about it, one shot gives you 90 then where does the end of the pipe go if were to try feeding the pipe through to do another bend. It will hit the hydraulic jack.

[FieryFurnace]

Welcome aboard friend! I thought you had said a 4-6 inch radius.....man diameter.....that IS tight! LOL

KY Metro: I think HW's pipe bending jig would do the trick. We could size the die down to what you would need and add a bending handle 6-8 feet long.

[Fosterob]

For all the effort you have put and are continuing to put into researching, making, scrounging and talking about this you could have all seven of those bent in a few hours by filling with sand. The bends should look like they were done on a mandrel bender and it takes very little equipment to do.
Rob

[HWHII]

Man if you get a minute I would like to see how you rig that up in the hossfeld. Thanks.

Nuge I will rework it and post some pictures for you.

[HWHII]

Nuge, Here are the photos. I am glad you asked, because this is a job that would have just sat there in the I would like to do that pile but don't want to take the time to do it. Now I will use it alot. It only took a couple of hours.