well im building my chassis now (book +4) and im going to need to bend the pipe on the rear and im also going to be making a rollcage and a pair of exhausts for it so will need something to bend the pipe. does the bender in the link look good enough for what i need?? will it be accurate enough etc?? how did everyone else do theirs?? thanks.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=120362963599#ebayphotohosting

No, the pipes will crease.
Unless you want to spend lots of time building a bender, then let someone with the £8000 machine do it for you.

i bought one like that a few years back. wasn't overly impressed to be honest. it kept kinking the tube. maybe it was something i was doing wrong (tube too thin, pipe spring too small etc)

Good for scaffold tube, internet shows people using these to bend exhausts, cages etc when the tube is stuffed with sand and capped.

I have one myself, hardly get any use as it always kinks thin tube.

When I made may chassis I selected some nice school chairs and cut the bends out for the frame, paid a tube bender to put some turns in my roll cage.

IMHO better to save your pennies in this instance and spend the cash on preformed bends.

Regards Mark

If you can get a hold of Martin Keenan from MK engineering, he has the bending kit.
It depends where you are. I finally tracked someone down in Mitcham Surrey called Loughboro Designs who rolled my MotaLeira rails.
I supplied them conduit templates to work from as I am an Electrician and have my own conduit bender.

i know of somewhere that can do it all just i would prefer to do it in house.

I got one of those.
I'll sell it to you for half that price..

You'll be wasting your money though.
they are C**p

David

quote:

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Originally posted by Z20let Corsa
i know of somewhere that can do it all just i would prefer to do it in house.

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quote:

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Originally posted by dogwood
I got one of those.
I'll sell it to you for half that price..

You'll be wasting your money though.
they are C**p

David

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No.......



I haven'r found anything that they bend nicely.

Exhaust tube defo no no, too thin
Also tried 50mmx3mm roll bar tubing..
Compleatly fraked that

tried filling with sand, tried heating it a bit.
only a propane gun but cherry red.
still creased....

David

[Edited on 17/1/09 by dogwood]

Not unless you want to use 3-4mm wall thickness and want you want your car to weigh over 1000kg!

Evening, u need a mandrel bender to do the thin wall stuff, and specific tooling for each Dia, not worth investing in unless u are going into production. A decent set up will cost in the region of £6000 minimum with one or two formers/mandrels, although u can get reasonable results with the packed sand technique once u master it. Its like everything else practice makes perfect. U will wreak quite a bit of metal on the trial runs though
Shug

[Edited on 17/1/09 by Hugh Paterson]

ok. i havnt really thought about it but how do i know how long to cut the rollbars etc before i get them bent. do i just do the width+height+height or what?? dont know if the radius on the bends will make it need to be longer or shorter or what??

I'd just take the tube to the place to bend it, in as long a piece as possible, and let them bend and cut

Hmmm i've bent 2.5mm wall 33.7mm tube with the machine mart version of that bender loads of times and never had an issue, no wrinkles or flattening in bends under 90 deg. Just go nice and slow and make sure the piece is firmly in the former and centered - no problems.

As far as the back rails are concerned this method works pretty well, you can also heat with mapp gas and bend by hand but you need to get the tube pretty hot and keep the flame moving. I haven't found a locost method for the roll bar yet and will probably have to buy this.

Hi.

As Al Murry would say, "The clues in the name." Pipe Bender.

In engineering circles thin wall stuff that we use for exhausts is normally made to an O/D size
(i.e. 2"o/d 16swg) and is referred to as "tube", hence you need a "Tube Bender" to form it.

Thicker wall stuff is referred to as "Pipe" and is sized according to its "Nominal Bore", hence "Pipe Bender".

1/2" pipe is about 7/8"o/d (22.2mm)
3/4" = 1 1/16"o/d
1" = 1 5/16" o/d
1 1/2" = 1 7/8" o/d
2" = 2 3/8" o/d

The bore of pipe varies according to the wall thickness or "Schedule" (i.e. 10, 20, 40, 80 etc) but the
o/d remains the same, hence it is called "Nominal Bore Pipe".

A pipe bender will come with formers to bend Nominal Bore Pipe.


I made a pipe bender, but not the formers, (see pic below) and used it to bend my top bones
(1/2"nb x sch10 stainless) and also my roll bar, or "high level brake light bracket" as I prefer to call it
(1 1/2" sch40 stainless) but I must confess I use it more as a hydraulic press than I do as a bender.


Hope this post is helpful.

Cheers
Paul G
Rescued attachment Bender-081-s.jpg

Now THATS a pipe bender, cunning use of threaded bar
Shug

I made my roll bar from gas pipe and it bent perfectly I know its only steam grade pipe but at almost 4mm wall thickness with rear bracing it is more likley to damage the chassis mountings than break the bar.


Me and my car


part way through the rebuild.

The mounts can be seen here

We used a pipe kinker like that to do some years ago and found if you used packing you could get a reasonable result on tube but it still wasn't perfect.

I've used one on many occassions to build roll cages, I haven't had any problems at all. The only exception being when I tried to bend some thinner wall stuff. It kinked quite badly. If your bending a cage, do you really want it to be thin wall anyway? I'd use at least 3.2mm wall and more probably 4mm for a cage. Rememeber its your life that may depend on it.

For the rear rail tubes, you could try my technique which simply involved a suitably sized former and a little elbow grease:


Bending rear rail tubes

I built my bones with a protool bender and plan to do my tube chassis and roll bar with it too

The difference between pipe and tube has already been highlitghted

see my build diary link for pics