Next project-mandrel bender

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Well I'm starting to finish up my spring compressor and the rim clamp is about half done now so I found a new project to tackle.  I needed to bend some exhaust the other day and started thinking about benders.  They are crazy expensive!  I've been wanting to build a JD2 type bender also, so I started looking into building a bender that could do bothe exhaust and tube.  Came across some good videos on youtube of mandrel benders and then got to thinking.  A few years ago I bought an electrical conduit bender, a greenlee 555.  I knew a guy that owned an electrical company and needed the money so I got a really good deal on it.  Thought I would try it out for a pipe/tube bender and it works alright but not the best solution.  So after some thinking and downloading some parts diagrams I think that I can take the drive parts for the greenlee bender and turn it into a mandrel bender.  It has a double chain reduction gear setup so should have plenty of power, It's rated to bend 2 1/2" rigid thick walled conduit so it should be able to do 3" exhaust without blinking.This project is still a little ways off since I want to finish up some of my other projects first(I'm out of room in the garage!) but I'm starting the planning and research now so it's ready to go once I'm ready.  I have all the drive parts, just have to make a frame and mount the drive parts. As far as dies,  I'm probably going to buy one set used so I can mock this all up and use this set for a template to make other dies.  Once I find a lathe I am going to attempt to make my own dies.  There was a thread a couple weeks ago about using a lathe to make dies and some good pictures of a homemade tool one of the members made to accomplish this.The mandrel part shouldn't be to hard.  There are a couple options of what shape to use for the mandrel but I will start out with a simple ball shape attached to a peice of pipe.  The tube being bent will slide over this and when the bend is done I will use an air cylinder to remove the mandrel from the pipe.I don't see many big challenges in this project since I already have the drive portion to steal the parts from, think the hardest part will be matching the dies to it.  Here is a good video to see the type of bender I'm going to try and build.  Any advice/criticism is welcome![ame="http://www.youtube.com/watch?v=9CM6Rf4MqYo"]http://www.youtube.com/watch?v=9CM6Rf4MqYo[/ame]
Reply:Building a mandrel bender is going to be quite a project! Be sure to post lots of pics as the build progresses.If you don't have a copy already, I recommend , "Pipe & Tube Bending Manual" by John Gillanders, ISBN 1-881113-06-X. The book provides a good overview of different bending procedures and equipment, and has an excellent reference section.One thing to consider, when using a rotary draw mandrel bender, as the wall thickness of the tubing decreases, the degree of difficulty increases. Die fit and finish is very critical.Rex
Reply:Originally Posted by rode2rouenBuilding a mandrel bender is going to be quite a project! Be sure to post lots of pics as the build progresses.If you don't have a copy already, I recommend , "Pipe & Tube Bending Manual" by John Gillanders, ISBN 1-881113-06-X. The book provides a good overview of different bending procedures and equipment, and has an excellent reference section.One thing to consider, when using a rotary draw mandrel bender, as the wall thickness of the tubing decreases, the degree of difficulty increases. Die fit and finish is very critical.Rex
Reply:Not to be a pessimist, but a mandrel bender??? I think you may have bitten off more than you can chew. That is a very big undertaking!Check out this guys home built CNC bender.http://www.offroadfabnet.com/forums/...project+banditHis name is Clint. He's was an engineer student at the time. Very good progress pics and explanation. Keep in mind, this is NOT a mandrel bender. I don't think you understand the concept. It is not something that is just put together. There is a tremendous amount of research and design.I wish you the absolute best, but please make sure you do your homework.Grantp.s. The offroadfabnet.com  site has a guy designing another CNC bender. Check it out.http://jackalopefab.com/MM210Synchrowave 200DXMiller XMT350 w/60series feederMiller Bobcat 250 with SGA 100 and spoolgunHTP PlasmaFull Machine shop with everything
Reply:I know it's going to be a hill to climb but I think that it can be done.  I have been watching lots of videos and reading as much as I can to learn the basics.  I'm going to start with a table/stand and get the drive parts mounted.  Then the real work will begin with getting the dies and backplate made up and experement with them to get everything lined up.  Then start the mandrel fab.  I still have lots to work out/learn but that's why I started this thread before I start the build.  I want to finish my pnuematic strut spring compressor and rim clamp  before I start the bender.  I had a lot of issues to work out with the spring compressor and the rim clamp which I learned as I went and overcame them all so far.  I like challanges and designing/building my own tools.  It might take a couple attempts to get it right but what fun would it be if I just fabbed some peices together and everything worked perfect!  I'll be the site ginnie pig and try and get the kinks worked out and then anyone that want's to build one will have an example to follow!Thanks for the link I will get over to that site and read all I can.
Reply:Thanks again for that link Grant,  I spent probably 4 hours on there reading about bending and that bender the engineer built.   That's a pretty neat bender he built to be able to bend 180* in one stroke.
Reply:Originally Posted by ponch37300What exactly do you mean by "as the wall thickness of the tubing decreases, the degree of difficulty increases"?
Reply:I work with a mandrel bender, an old pines #2.  It does a great job and is easy enough to understand when you look at it, but this is not something that anyone short of an extremely talented fabricator/machinist/engineer is going to be able to make.  You cant even begin to compare this to a conduit/jd2 bender.  Have you ever seen one up close?Its like comparing a mobile home to a multi-million dollar mansion.  Yes, they both provide a roof over your head but as far as what is involved in making one...Have we all gone mad?
Reply:Originally Posted by sn0border88I work with a mandrel bender, an old pines #2.  It does a great job and is easy enough to understand when you look at it, but this is not something that anyone short of an extremely talented fabricator/machinist/engineer is going to be able to make.  You cant even begin to compare this to a conduit/jd2 bender.  Have you ever seen one up close?Its like comparing a mobile home to a multi-million dollar mansion.  Yes, they both provide a roof over your head but as far as what is involved in making one...
Reply:Well guys like I've mentioned in my previous posts I understand that this is a pretty advanced project and that it is going to big a mountain to climb.  But the more searching I do the more I find others have built mandrel benders and been succesful.  I may end up putting a lot of time into this and have it fail but I'm willing to take that chance. I appreciate you being real and trying to keep me from wasting time and money but I'm still going to go forward with this project this winter.  Thanks, Scott
Reply:Originally Posted by ponch37300 But the more searching I do the more I find others have built mandrel benders and been succesful.
Reply:Originally Posted by jackalopePLEASE post the links for this. I would love to see these as it would give me ideas for other projects. I have not found ANY home built MANDREL benders and I have looked. Many thanks! Grant
Reply:Originally Posted by wannabe_welderhttp://lmgtfy.com/?q=mandrel+bender+plansTry this link
Reply:Originally Posted by wannabe_welderhttp://lmgtfy.com/?q=mandrel+bender+plansTry this link
Reply:Hey, ponch,This might save you a bunch of time & $$:http://cgi.ebay.com/Mandrel-tube-pip...d=p3286.c0.m14Rex
Reply:Originally Posted by rode2rouenHey, ponch,This might save you a bunch of time & $$:http://cgi.ebay.com/Mandrel-tube-pip...d=p3286.c0.m14Rex
Reply:Die sets for these can be north of $1,000. Standard die sets for rotary draw benders are expensive enough at $300 a pop.At some point you have to ask yourself, "will I be able to make enough $$ to justify the cost and time?" If you are only bending up a few hundred pieces of exhaust tube and not tens of thousands, the answer for me would be HELL NO.To each his own.http://jackalopefab.com/MM210Synchrowave 200DXMiller XMT350 w/60series feederMiller Bobcat 250 with SGA 100 and spoolgunHTP PlasmaFull Machine shop with everything
Reply:everyone else has been kind.......then you got all cocky.let me be the first to point and laugh.your an idiot.
Reply:Originally Posted by dsergisoneveryone else has been kind.......then you got all cocky.let me be the first to point and laugh.your an idiot.
Reply:Originally Posted by dsergisoneveryone else has been kind.......then you got all cocky.let me be the first to point and laugh.your an idiot.
Reply:Originally Posted by jackalopeNice try! Not anything found but crap links. Just because something bends tube does NOT make it a MANDREL Bender.Perhaps some DIRECT links to actual HOMEMADE Mandrel Benders would be useful!
Reply:Originally Posted by sn0border88Hey smartass, you do realize that nothing on the first few pages of that link have anything to do with someone making their own MANDREL bender. You could at least try not to look like an idiot.
Reply:Wanna-be,  I will assume you are your namesake and that you are also a web-"wheeler" as far as your skills are concerned.The link you posted is obviously useless. I'm sure if I searched long enough I could figure out that your internal composition is based entirely on PPP (piss poor protoplasm). The point IS, there is NO direct link. I think this reflects your inability to produce.I'll lay off the criticism of you as it detracts from the OP and is useless.I am still awaiting a direct link from anyone that has one!Granthttp://jackalopefab.com/MM210Synchrowave 200DXMiller XMT350 w/60series feederMiller Bobcat 250 with SGA 100 and spoolgunHTP PlasmaFull Machine shop with everything
Reply:Wow this thread took a turn for the worse.  Think I'll just let this post phase out since this just turned into a pissing match about google.Grant,  It was late at night when I was searching and found the homemade mandrel benders.  It took a lot of searching to mind any info on homemade ones.  Here is one link to one a guy made.  I sent him a PM about some details and he said he hasn't had time to finish the mandrel part yet, he made the mandrel insert but hasn't put it all together yet.  He said this winter he will finish it up.  When I get some time I will do some more searching I will try and find the other ones I saw(I know I should've saved them but it was late!).  http://www.offroadfabnet.com/forums/...ead.php?t=1661There is a lot of good articles on mandrel bending and how to set up a mandrel bender.  This is something that I want to try and I'm a pretty stubern person so I will be making an attempt at it.  I have the motor, gearbox, and a lot of the other parts so if it doesn't ever end up bending any pipe I'm not going to be out much besides the cost of metal and some time so I can live with that lose if this never gets working.  At least I will have some quality time in the shop.  I understand that there is a pretty good shot that it might not work out on the first try or even might not work out at all but that's a risk I'm willing to take.  Heck, the wright brothers built a plane when everyone told them it couldn't be done.  It took them a lot of attempts and work but they completed it.   I probably won't post anymore on this since it's created a pretty big stir up.  Thanks, ScottPS-Grant, I've looked at your work and shop pics and you do some quality work and I respect your opinion!  So I know this will be a HUGE challenge if someone of your caliber is doubting it.Last edited by ponch37300; 10-01-2009 at 01:09 PM.
Reply:Ponch,  Definately post pics here or over on the other ofn site. I would love for youto "prove us wrong." I am not skeptical but more of a realist. I know what kind of time and machinery it will take to get this done and it ain't no small task. Being stubborn and being persistent are too different things totally. Be smart about your approach to this.  As for the link you provided, that is a standard rotary bender that he "claims" will be made into a mandrel bender. I was following that a year ago and it fell of the map.  Again, if you find those links, let me know. I would love to see how people tackled some very complex issues.Granthttp://jackalopefab.com/MM210Synchrowave 200DXMiller XMT350 w/60series feederMiller Bobcat 250 with SGA 100 and spoolgunHTP PlasmaFull Machine shop with everythingI know that one isn't finished but he did make a pretty neat mandrel.  I don't know if you've seen this site before but I found it has a lot of good info on mandrel bending and the different parts.  If you search threw the site it tells exactly how to set up a mandrel bender.  http://www.bendtooling.com/index.htmI am a realist also, in the fact that I very well understand that this isn't going to be a couple of weekends doing some work and drinking some beers in the garage!  I am trying to gather as much info on mandrel bending as possible right now and come up with a design.  That is why I posted this so early, hoping to get some feedback on how to go about this.  I will post pics as the build progresses to get some constructive critism.Thanks, Scott
Reply:i guess it was wanna-be with the Let Me Google It For You.  the "I wanna build a mandrel bender, it cant be hard" got me going.I see now the OP  Ponchxxxx wasnt the one wo did that.i fly off the handle occasionally.i also fail to punctuate occasionally.im no still, mandrel bending (bending with an inner support) isnt something you can whip up with some chain reduction and a home made die.further, a true inner mandrel may be unnecessary, as a good bender can bend tube packed with sand (or whatever), and get some benefit.Last edited by dsergison; 10-01-2009 at 01:52 PM.
Reply:Originally Posted by ponch37300I am a realist also, in the fact that I very well understand that this isn't going to be a couple of weekends doing some work and drinking some beers in the garage!  I am trying to gather as much info on mandrel bending as possible right now and come up with a design.  That is why I posted this so early, hoping to get some feedback on how to go about this.  I will post pics as the build progresses to get some constructive critism.Thanks, Scott
Reply:"I don't see many big challenges in this project since I already have the drive portion to steal the parts from"well then, best of luck to you.  -nope, just couldnt keep my mouth shut.
Reply:Originally Posted by jackalopeWanna-be,  I will assume you are your namesake and that you are also a web-"wheeler" as far as your skills are concerned.The link you posted is obviously useless. I'm sure if I searched long enough I could figure out that your internal composition is based entirely on PPP (piss poor protoplasm). The point IS, there is NO direct link. I think this reflects your inability to produce.I'll lay off the criticism of you as it detracts from the OP and is useless.I am still awaiting a direct link from anyone that has one!Grant
Reply:Originally Posted by wannabe_welderWhile it's true that I'm not a fabricator of the class of many on here,.
Reply:Originally Posted by dsergison"I don't see many big challenges in this project since I already have the drive portion to steal the parts from"well then, best of luck to you.  -nope, just couldnt keep my mouth shut.
Reply:I have actually seen two mandrel benders that appeared to be self built.  One for sure and the other one I would bet on it.I used to go down to Wichita to a company that did a lot of fabrication for the aircraft industry and they had 3 or 4 big Pines benders and rack upon rack of tooling for them.  I remember being shown a piece of 4" x .028" stainless that was bent on a 4" C.L.R. with no kinks.  WOW!  Any way, over in the corner and covered in dust was what appeared to me to be a home built version of a mandrel machine.  No castings, all weldments using a lot of structural shapes.  I never did ask but I would about bet that that machine might have been the tool that started the company on the road to what it became.  Just a guess on my part though.Here is a drawing that I started on of the basic part of how that one was done.  It used a double acting cylinder mounted to the beam on one side and a solid bar on the other side that would slide horizontally in mounts and the chain on each end traversed on the sprockets.  Just changing lineal motion to rotary.The clamping action for the clamp die and the follow block were over center slides, no hydraulics other than the main cylinder.I've wished a thousand times that I had taken some pictures and measurements on that machine.The second machine was one that a fellow built himself to use in his sideline building dragster chassis.  He built his dies from aluminum as he was not doing thousands of bends.  On his, he just used a single acting cylinder in a pull mode and had a couple of large garage door springs to do the returning after the bend.  For extracting the mandrel. he had a threaded rod on the end of the mandrel rod and a nut.  He used an impact wrench and a  socket to pull it out.This machine would not be well suited for production work as it was pretty slow and required a lot of fiddling but it produced good results.  Thin wall 4130 is not the easiest thing in the world to bend.