Bend the end of a pipe to a point?????

admin

I have a project coming up soon where we will be pulling 120' of 30" diameter pipe into the ground.  Those of you who may be familiar with directional drilling know that you cant really get a pull head this big to attach to the pipe for the drill to pull.  I have made custom pull heads before but for some reason the boss wants to bend the end of the pipe we are pulling into a point and attach a pulling eye on this one.  I have no idea how to do the math and measurements on a round pipe to bend it into a point using four sides, or whatever number of sides necessary to make a point.  I have seen in electrical forums where they spread the end of a conduit a bit, cut a wedge out, then bend it in on itself to form an almost perfect point.  But I cant do that with a 30" diameter pipe, obviously.  The bends have to allow me to close the end of the pipe completely after welding so that no drill mud can enter the end of the pipe.  So just cutting for slits and bending is not an option since the corners at the bend will open up like tear drops and it will take five thousand rods to fill the holes.  I have some ideas in my head but I have no idea how to do the math to make it work.  Has anyone ever had to do a bend like this?  I'm assuming the math on a 1" pipe is the same for a 1,000,000" pipe so whatever you got, I can use it.  Thanks!
Reply:You are looking to do an orange peel. (modified to make a long point) The math of each of the petals, where the horizontal line crosses, is the circumference desired at the distance from the baseline.You'll likely want to make the petals longer so you can go to a point instead of a dome.

You'll need more than 4 petals of course.

Last edited by MinnesotaDave; 04-10-2018 at 07:20 PM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Thanks.  That was extremely helpful.  I think a dome would actually be better than a point in this case anyway.  I just figured a point was easier but this looks like something I can pull off.  I hope it doesn't take me three days to heat and bend though.  30" is a lot of pipe.  And this looks a lot easier than what I was going to try to finagle.
Reply:Sorry I can't help you out with a mathematical method to do this... normally on similar projects I make cardboard templates and go from that

A simple sawtooth pattern with at least 20 tabs is what I would aim for however... because of the curvature of the pipe you won't be able to 'bend' the 'tabs' that are left....well at least not without some sort of tearing or collateral bending elsewhere you didn't want... or using a whole lot of heat!!!  by your post I am assuming he doesn't want a 'cap' that fastens to the end like we do in pipe bursting and ddrilling. You didn't mention schedule of pipe but I'm guessing it's wall is gonna be upwards of 1/2inch.... would be far simpler to cut profiles to make a point or semi sphere point and weld it up then weld it to the pipe.With a 30 inch pipe diameter you're going to have a circumference of well over 100 inches so any tabs over 5-6 inches will still have about a half inch of roundness to them and make them a pain to bend uniformly... there are also a few other things that will be affected more depending on the schedule of pipe. I see Dave beat me to it

with a much better replyLast edited by ronsii; 04-10-2018 at 07:36 PM.
Reply:https://www.dailymotion.com/video/x6fcr50
Reply:orange peel cap.little black book linked herehttps://pipefitting.browntechnical.o...SABEgIr6fD_BwEnot sure if it will lay you out to 30" but will help give you an ideabosses stuff:trailblazer 325maxstar 200my stuff:sa 200fronius transpocket 180100 amp Lincoln w/f97 f350 DITKevin
Reply:

Originally Posted by ronsii

Sorry I can't help you out with a mathematical method to do this... normally on similar projects I make cardboard templates and go from that

A simple sawtooth pattern with at least 20 tabs is what I would aim for however... because of the curvature of the pipe you won't be able to 'bend' the 'tabs' that are left....well at least not without some sort of tearing or collateral bending elsewhere you didn't want... or using a whole lot of heat!!!  by your post I am assuming he doesn't want a 'cap' that fastens to the end like we do in pipe bursting and ddrilling. You didn't mention schedule of pipe but I'm guessing it's wall is gonna be upwards of 1/2inch.... would be far simpler to cut profiles to make a point or semi sphere point and weld it up then weld it to the pipe.With a 30 inch pipe diameter you're going to have a circumference of well over 100 inches so any tabs over 5-6 inches will still have about a half inch of roundness to them and make them a pain to bend uniformly... there are also a few other things that will be affected more depending on the schedule of pipe. I see Dave beat me to it

with a much better reply
Reply:What about cap end and use square tube or pipe as a frame to make a cone. If that open frame would fill up then cut and tack plate to the frame. That's a lot of pipe to be pulling.This might be similar to what you did after rereading your post.
Reply:you could use a weld on concentric reducer, or two to get down to a manageable size.Lincolin Power Wave 450, Lincoln Powermig 255, Lincoln Pro Mig 140, Lincoln Squarewave Tig 275, Miller Big 40 G(with Hobart Hefty suitcase), Thermal Arc 95S and Esab PCM875 in an already full machine shop.
Reply:

Originally Posted by propanehotrod

you could use a weld on concentric reducer, or two to get down to a manageable size.
Reply:I was thinking possibly rolling one if you have access to a roller?  The orange peel idea looks intriguing also.  Are you going to cap the pipe before putting on the cone so no mud gets into the pipe and possibly only the cone?  It would be easy to cut a circle out and put it on before the cone goes on.  I've never pulled anything before but just throwing out some ideas.  A plasma table would make short work cutting that stuff out.
Reply:how many tons of force does pulling 30" take? I would be worried the orange peel would separate pulling from the center because of the flex  if it snags at all, at least  if its thin pipe, under 1/2 wall, and the amount of time orange peeling that would take. what about a 2" plate welded in the end, sub to that with guide/sled fins to keep from digging in.Do not argue with an idiot. He will drag you down to his level and beat you with experience.
Reply:Im not worried about it anymore.  I guess the boss man wants to let his nephew do it.  Im pretty sure its 1/8" and its at least 40 tons or more pressure.  Im assuming its a lot because the drill we are using is capable of pulling 80 tons and we arent using our other drill which makes me think it exceeds its limits.  I kind of hope the end does come off because instead of shaping the end of the pipe, he wants to make the orange peel cap and weld it on.  I am still welding the pipes together but Im not making the cap.  I think his nephew should come weld the cap on so when it comes off, everyone will know whos fault it was.  I need a new job ha.
Reply:Well definitely get some pics if you can

I for one would like to see how  it gets done... or at least how it gets attempted


Reply:I laugh when threads like these pop up.  I imagine kids sitting in Algebra and Geometry classes saying "this is stupid and I'm never going to use this stuff"  LOL
Reply:If you've never made an orange peel, I recommend folks make one anyway, maybe not quite that large.  They are a lot of fun and good experience should the need ever arise.  I made my first one for a post out of 3" pipe so it would have a smooth, rounded closed off top.  I just cut the "ears" with an angle grinder and bent them over.  Lot of fun to make.