Tube benders

[baldkev]

Hi all,

Do any if you metal guys have any tips for tube bending? Ive got a manual rotary draw bender ( 32mm dies ) which i bought about 15 years ago and haven't really used. I tried when i got it but the first pipe deformed badly so i bought cold drawn tube and it was a bit better but still deformed badly so i gave up!

I also bought a roller bender at the same time. It worked great on 1" galv tube!
More recently i had to bend some tube ( 2", the customer had some 2mm, it deformed badly as the bend went on and created a v on the inside of the tube despite going slow and steady next i got some 3mm and that was better, but still did the v by the time we got down to the required radius.... which was about a quater of a 1500mm diameter circle

So..... can you give me some hints or tips?

Thank you, kev

 

[baldkev]

This is the roller bender. I can get piks of the rotary draw next time i am at the workshop.

 

[gregmcateer]

2 inch is going to be a challenge by hand, I'd think. 22mm chipper is pretty demanding, though I am a10 stone weakling!
Not sure what options are out there

 

[baldkev]

The rotary draw has 32mm dies, so I'll probably be aiming to do 32mm on that. Originally i wanted to build a motorbike frame ( and still want to! ) but at the mo im thinking of making a new hardtop for my truck. The existing options seem a lot of money being as they all seem based on the same weak locking system.... my current fibreglass top has been rubbush since day 1 and now it leaks through the roof bar fixings. I coukd fix all the issues but i can break into it without hasstle, which means so can anyone else!

 

[Phil Pascoe]

I have heard of people filling tubes with sand and sealing the ends before bending.

 

[baldkev]

Yep, better than liquid due to the heat welding the ends up theres slso springs i believe that people use to brace the tube.... is there a good wall thickness or type of type that bends well? The rotary probably produces a 90 over about 10 /12" of tube

 

[Devmeister]

I gave up years ago on benders. Last tubing project was a heat exchanger. I placed flare fittings on both ends of the copper tubing and filled it with water. Make sure you get all the air out. Caps thread into the flare fittings to seal everything. Then I turned a wood cylinder to the ID of the coil. Then you man handle the tubi g around the form. It gets harder as you go and the pressure in the tubing gets very high. Then slip off the mandrel and cut the ends off. I use this method to bend lube lines for my milling machine. Make a wooden form and follow the tubing in the form. This type of bending is difficult because of the shape but be patient. Since doing it this way I have never kinked a bend.

 

[Spectric]

I used to have a Tubbella, a heavy beast with hydraulic ram and that was not bad upto 2 inches. When bending thin wall pipe such as exhaust and the like I used to know a firm that had a pipe bender that pulled steel balls through the pipe as it formed the bend, no deformation and it could turn pipe into spaghetti. If you want really intricate and tight bends then you will need to fabricate and weld, much easier these days as the patterns can be laser cut, much easier than Gilbows.

 

[Ttrees]

Not sure if its any use to you, but this fella has a few videos on the subject.
Quite a bit of effort involved

 

[JBaz]

I recently needed to bend some 27mm diameter galvanised steel tubes with 2.6mm wall thickness to a radius of about 1m. I bought a (new) 3-roller tube bender for the job which came with 3 sets of rollers/dies, none of which were for 27mm tube. I believe that you need to have the dies snug against tube for half its circumference to stop the pipe deforming outwards and creasing, so with the help of a tool I made for my lathe I took the 1" die out to 27mm.

Bending such thick-walled tubing took quite a lot of force, but by taking it gradually - lots of passes through the bender - it did come to the required radius without distorting the profile. I did have to make sure that the tube didn't twist as it was bending, which I did by marking a centre line at each end. If I was to do the job again, I would probably clamp something to each end of the tube as a reference to indicate if any twisting occurred.

The job turned out fine and I'm intending to sell-on the 3 roller benders as I've no further use for them. The job was only 4 pieces so the benders are as new. Anybody interested please email me.

 

[baldkev]

Thank you everyone for your replies!
Ttrees: i hadnt even thought of youtube

Thank you all

 

[Fergie 307]

Haven't used the roller type for years. I do all mine with a hydraulic one, works a treat and about £100.

 

[Keith 66]

Machine mart do a 12ton Clarke one, It will bend everything up to & including steel scaffold poles, iirc about £149