tubing bender

[ThatGuy]

DOM would be your best bet for the cage.

To get out a little cheaper you can use HREW for the straight stringers but use the DOM for the main cage material and any place that has bends. Better to just use DOM throughout the whole cage that way you have no worries.

Also I'd use at least 1 5/8" tubing no less than .120 wall.








On a side note..... B&G those pics done nothing for your argument. Making a 9 degree bend in exhaust tubing is about all a pipe bender is good for. The picture you put up of the flat spot in the 40 degree bend is exactly what everyone has been trying to tell you. You need a tube bender to bend tube correctly.

 

[JohnnyU]

The material has little or no effect on anything if the design isn't there. A properly designed cage arguably is more important than the material used. Actually, I would say they are really highly dependent on each other. If you used HREW, you would design the structure differently than you would if you used DOM or Seamless, or regular black pipe (Yes, it's been done-sucessfully).

I think you need to scour the internet looking at cage designs and materials. Head to the library and do some research there too. Roll cages have been being designed way back when they still used to print books on paper, and there are some great resources out there.

 

[slammer67]

I've used cheap HF benders for years, the one I have now is a cummins tool, same thing only it's blue. I would definitely suggest getting something better, but the cheap benders can work if it's what you already got.
You shouldn't have any probs bending DOM in it, but with HREW and other tubes, you have to be picky when you shop. There are two metal supply places in the town I lived last that sold tubing, the tube from one place would kink every time, the tube from the other would bend easily, even though the tubes were supposedly the same from each place (HREW)

There are some things you can do to help the cheap benders make better bends.
one is to spray the dies and the pipe with wd40 or other lube to minimize friction.
The sand trick does work, but you have to pack the sand in good to keep it from kinking.
somewhere on youtube, there's a vid of a guy who shows how to pack the tube with sand - it's pretty good, he fills it with water, adds the sand while tapping the sides until he gets the tube full- I dont feel like finding it for you right now, but it should be easy to find.

You can do a cage successfully in HREW, I bet there's thousands out there. Ive done 3 or 4 myself, at least two I know that were put to the test, but like was said already, you have to design accordingly i.e. more triangulation, shorter straight spans, etc.

If you have a budget to buy DOM tubing, then you should be looking at something better than a HF bender

and post some pics of the project

 

[B&G_Automotive]

On a side note..... B&G those pics done nothing for your argument. Making a 9 degree bend in exhaust tubing is about all a pipe bender is good for. The picture you put up of the flat spot in the 40 degree bend is exactly what everyone has been trying to tell you. You need a tube bender to bend tube correctly.

I think it does allot for the argument as that bend has not kink one. I knew as soon as I posted the picture that would be immediately overlooked, and the picture makes it look flatter than it really is. The whole argument has not been about how it flattens out tubing, it has been that it kinks it. Like I said before if you are building a roll cage for a NASA vehicle and a perfect bend profile is desired we should be using a mandrel bender. Even the beloved JD2 everyone is raving over does not make a perfect bend, it to flattens out the tubing. But for any normal person who doesn’t have to pass NASCAR tech a properly done kink free bend in the pipe bender is going to be just as structurally sound as one coming out of your JD2. So whatever if you want to blow almost a thousand to do a few projects fine by all means do it I’m not going to loose any sleep. For those who want to bend up some tubing or some exhaust and don’t want to break the bank pay no mind to these wanna be structural engineers there are alternatives.

 

[railman]

I knew as soon as I posted the picture that would be immediately overlooked, and the picture makes it look flatter than it really is. The whole argument has not been about how it flattens out tubing , it has been that it kinks it. Like I said before if you are building a roll cage for a NASA vehicle and a perfect bend profile is desired we should be using a mandrel bender. Even the beloved JD2 everyone is raving over does not make a perfect bend, it to flattens out the tubing. But for any normal person who doesn’t have to pass NASCAR tech a properly done kink free bend in the pipe bender is going to be just as structurally sound as one coming out of your JD2. So whatever if you want to blow almost a thousand to do a few projects fine by all means do it I’m not going to loose any sleep. For those who want to bend up some tubing or some exhaust and don’t want to break the bank pay no mind to these wanna be structural engineers there are alternatives.

flattening out is the start of a kink....so most people look at the two as the same....

ummm...the JD2 is a mandrel bender....and no it doesn't flatten it out at all...

only way a JD2 could possibly flatten out anything would be if you weren't useing the right size dies for the tube/pipe you are bending...

as for blowing a thousand for a "few" projects.....that is his decision...we said use the HF one for that....we are just saying to use something better for a roll cage....cause any flat spot in a bend will fail first....period

and you don't need a structural engineering degree for common sense....

l8r, John

 

[gwaii]

when using the JD2 the flattening happens on the outside of the bend,from the metal being stretched into a longer length.there is no way to support this part of the tube(it would need to be supported from the inside)unless you pack it with sand.the inside radius is supported by the die,so the compression on this part of the bend still forms a nice circle.as i stated before,for anyone that has a JD2,go bend a piece of tube and cut it across the bend.the profile will be somewhat D shaped.and yes,that is with the proper size dies.don't get me wrong,i like my JD2,it's a good machine...just don't go thinking that it will perform miracles.for exhaust work i always buy j-bends and cut the curves i need from those.most still have some distortion(like dynomax)but the more expensive ones such as hooker's are perfect.how?simple-after forming the bend,the force a steel ball through the inside of the bend with hydraulic pressure to reform the profile.that's becaues even with their million dollar production macines they still can't get a distortion free bend.

 

[JohnnyU]

as for blowing a thousand for a "few" projects.....that is his decision...we said use the HF one for that....we are just saying to use something better for a roll cage....cause any flat spot in a bend will fail first....period

Especially when "blowing a thousand" might be the last thousand you get to "blow" if the cage fails....

 

[B&G_Automotive]

flattening out is the start of a kink....so most people look at the two as the same....

ummm...the JD2 is a mandrel bender....and no it doesn't flatten it out at all...

only way a JD2 could possibly flatten out anything would be if you weren't useing the right size dies for the tube/pipe you are bending...

You are smoking crack, JD2 is not a mandrel bender go do a google search before blasting me with your ignorance.

A flat spot is not a kink, go look at some comercial made roll cages like on UTV's such as a polaris ranger, or look at the ROPS on utility tractors. Those bends are far from perfect and if they were totally unsafe those companys would not be in business from all the wrongful death lawsuits and injury claims.

 

[gwaii]

here you go,so you nkow what i'm talking about.on the left is an unbent section of tube,the right a cut across the bend.this is 1 5/8 .120 crew bent on the JD2 bender...it's typical for all materials and sizes.and as for the cost of tools,i've never gone wrong buying the best i could afford at the time,and kept the willingness to upgrade when the means allow.

 

[BlackBII]

Wow 4 pages of this?

Lol.

The HF bender isn't designed to bend Tube, so it can kink and flatten it.

If you want good bends, go with a real bender that was designed for it.

 

[JohnnyU]

The real difference here is how the bend is made....

The pipe benders in question force the bend from the center, and stretch outward in both directions with little support to the tube. This causes much higher stress in the outer surface of the tube and thus can cause flattening. The fixed die is also the cause of the kinking on the inner surface of the tube.

The tube benders (such as the Protools 105, JD2, etc) actually revolve the bend using a moving wiper die. This helps spread the stress of the bend over the entire length of the bend, lessening the deformation of the cross-section. This also creates much more uniform stress throughout the bend, resulting in a stronger bend as well. This "wiping" affect also helps reduce the kinking seen on the pipe benders. Will this still deform the tube? Of course, that's the whole purpose of a bend, is to deform a straight length of tube. The die design does help reduce the cross-sectional deformation, which is really what we're discussing here. Tube gets its strength from its cross-section, plain and simple. Once that is un-uniform, it creates stress concentrations and potential points of failure. Minimizing these is the name of the game. Notching, welding, and bending will all create dislocations and defects in the material, it's just a matter of taking this into account when designing the structure so that the structure does not fail. Like I said before, the design of the structure is critical.

Each tool has its own intended use and advantages/disadvantages. Using a tool for anything other than its intended use is never suggested, and can have detrimental results.

 

[86 slo-vo]

Sorry but do you struggle with literary comprehension? As you are the densest person I have ever argued with. Never once did I say you were not allowed to post a picture, I just stated that it was not constuctive to the topic at hand.

you were the one getting mad because i posted a picture of my bender and was "flaunting it" and useing up bandwith


Yes they are, they both bend tubing don't they?


Here is a Custom 3 inch H-pipe with QTP cutouts for a Mustang. I dont see any kinks or flat spots in those bends.

seriously? i can bend exhaust pipe that far with a torch and not kink it.


I have found through tweaking it that the flat spots are elimintated by fitting the radius of your roller dies to the pipe.

you have yet to show us a decend bend, or even some sort of your work that uses some real bends

Thank you Best tool no, most cost effective absolutely.

i may be "dense" but me as well as probably many other in here were to walk into any kind of "professional" shop and saw them bending up tube for a roll cage or anything of the sort would laugh and walk away.....when it comes to tools you get what you pay for...why are mandrel benders so high? because they are the best.

i am by far a professional, but i do plan on doing all my stuff and other peoples too

.

 

[86 slo-vo]

and just for comparison...here is a bend i did yesterday in under 3 minutes...

does the manual part suck? yea...but i do plan on going air over hydro

 

[B&G_Automotive]

and just for comparison...here is a bend i did yesterday in under 3 minutes...

Top looks flat I deem it unsafe.

Here is your internet cookie for being master pipe bender supreme, I submit to your greatness.

I dont care about nor require yours or anyone elses approval on here of the work that I do.

 

[86 slo-vo]

i would love to see you do the same bend and see what happens....im not sure why you continue to crack on me, must be jealousy

nice edit, im not looking to give or get aproval for anything i or you do, but before you come into the fabrication forming boasting about how amazing your HF bender is and how stupid we are for paying for overpriced "junk" you should get your facts straight on your tools

if i wanted to make 22.5 degree bends i would have went the cheep route, but i wanted more then that im not really sure why that has your panties up in such a wad