Tube benders

[alsorts]

Anybody used tube benders(like machine mart), is there any special way to use them when making a frame?What metal is best to use for frame building(car trike).

[devon-tony]

I have the clark one, is a very nice bit of kit, 12Tonne hydraulic and less than £100 delivered

but be aware that the formers are for BSP?? sizes, I found that one of them perfectly fits 42mm or 43mm cant remember :( tubing and that what I build mine from, will do nice bends with ease, does put a slight wrinkle on the inside of the bend if you are really going for a tight bend, but certainly well worth the money

[dracken1]

i take it you mean the bottle jack type?

firstly it's not a tube bender, it's a pipe bender.
the formers are sized to suit pipe, theres no support for the outside of the bend so crimping is a problem.

but on a certain american forum a lot of frames have been built using them.
trying to bend anything with less than a 3mm wall thickness is almost a recipe for disaster.
i'll say no more as i'm sure blackjack will have a thing or two to say on the subject.

btw thanks for the info you sent me blackjack, much appreciated...

[alsorts]

Yes its the bottle jack type.(Clarke)
Is there any way of stopping the metal folding when it is bent(support)or is it just the expensive machines.
I suppose its better to use seamless metal?

[mark4x4]

:eek: i use gas pipe for bending in mine, it comes in the imperial sizes and has a thick wall, its very strong and bendable...............

[Blackjack]

OH MY GOD.

"will do nice bends with ease, does put a slight wrinkle on the inside of the bend "

Well its crap then isn't it? A slight "waisting" of the tube is fine, wrinkles at 90 degrees to the axis of the tube are structural failures witing to happen.

"i use gas pipe for bending in mine, it comes in the imperial sizes and has a thick wall, its very strong and bendable..."

First of has it not occured to you that "bendable" is not a desirable quality for a motorcycle frame?? Pipe is a hollow cylinder that fluids or gases flow through. Tube is a structural material for making things out of. They are not the same thing.

Firstly use tube don't be tempted by pipe. You are building a frame not a central heating system.

If you have to use a push through bender use 1/8" or slightly thicker wall as it will bend better than thinner walled stuff. Then find the "shoe" that is slightly bigger than the O/D of the tube, and measure how much bigger it is. Say there is 1/8" of slack between the shoe and the tube. get some 1/16" soft aluminium and wrap it half way round the tube in a "U" shape. Then put the tube and the ally "U" section in the shoe and bend it all together. This should give you a shaped ally insert for the shoe, if it doesn't you might try annealing the ally and trying again.

Packing the tube with DRY sand and welding some ends on is reputed to help.

If you can score one of those benders that plumbers and electricians use (conduit bender) you can buy tube sized formers and guides for it. At least one of the top flight frame builders in this country uses one of them with the right formers and guides. Without any formers I've seen them for £20 second hand.

This is a better bet, and with the pound doing well against the dollar......

JD2 bender (http://www.jd2.com/M3B_Features.htm)

[mark4x4]

well i have been using gas pipe( steam pipe ) for years as do alot of builders, i have never had any problems at all, it has a thick wall and dosnt deform under bending, this pipe is what the clark pipe bender was made for bending :) my current 200bhp i.r.s trike HASNT CRACKED OR BROKE YET and you wouldnt want to see how its ridden. :cool:

[Blackjack]

The criterion I use for selecting material for a frame is how suitable it is for making frames out of.

I repeat that being easy to bend isn't a good quality for a frame to have. I'd also have doubts about the "weldablility" of gas or steam pipe as it's usually threaded and screwed together so it probably has a high lead content to promote freer cutting which tends to cause welds to undercut.

[Creature]

ill just keep quiet as i still bend mine around the washing line pole :)

[Blackjack]

That's because its copper pipe.

And what pray tell is a scaffolding if it isn't a structure??

Conduit is a conduit and neither tube nor pipe.

So I'm sorry but the statement is correct.

This however is flat out wrong 'Pipe can be threaded to join it and tube uses a mechanical clamping method'. Ever tried threading PVC waste pipe or garden hose pipe? And having cut internal and external threads in tubes before I don't see what the difficulty with that is.

I'm guessing here, but you're a pipe welder aren't you?

[dracken1]

I'm guessing here, but you're a pipe welder aren't you

he says he has asme9, as do i.

so yes, asme9 is lloyds talk for pipe welder. :D

[triker_gal]

nope, not gonna do it,, nope , nadda , aint nothing happening ere :D .

[Blackjack]

I think Dracken may be aware of my opinions on pipe welders.

As for that extraordinary long list of qualifications, well I can't possibly compete with that, I just build motor cycle frames for a living.

Though I did actually run a design and development department once. Well, actually I was the design and development dept.. That, and any other stupid job that wandered in the door. Nothing quite so exotic as the oil/gas industry though, just a motorcycle factory.

Don't suppose making all the jigs, writing all the job specs and doing all the drawings for limited run production frames counts for much either.

Course I wouldn't know much about tube bending either, that's why I have this............

[mark4x4]

well i build trikes and bikes and dont care :p who has what so my cheap pipe bender will have to do :D

[Gypsy]

ill just keep quiet as i still bend mine around the washing line pole :)


LMAO :D

[ROBBIE]

i use a old hillmore tube bender with a scaff pole welded onto the handle ,it can bend 10gauge mild,stainless no problem,i also have a cheap toolmart hydraulic bender which bends pipe up to 2" dia, i did have a problem with that leaving indentations in the tube where the pins are on the bender but got round that by making 2 stainless shells which go under the pins so s no marks are left now ,i must admit i wouldnt use any tube that was wrinkled ,and i dont use tube that undercuts when i weld it,also if you look at a lot of old motorcycle frames you can see poor welding even blowholes on the early jap stuff!,safe frame construction needs good welding,tube placement,correct tube be it seamless or erw& bent in the correct place(esp erw)but you do see a lot of horror stuff splatter welded n battered into submission by a mig

[dracken1]

i took my welding grades at bridge town cannock. in an ideal environment well lit, clean, lovely.
i was, at the time pipe welding on coal fired power stations.
if anyone has ever been in one of them places then you know they are some of the dustiest places going, a long way removed from welding school.

some very good advice blackjack gave on another forum, which i always do myself now,is.
if welding frames with mig i firstly tack them, then heat them to a dull straw colour, (thats the colour close to the cold end not the colour close to red) before finish welding.
a mig is a cold welder compared to a stick and there is very little penetration for the first 15mm of
the weld bead.
and it does make a hell of a difference..

[ROBBIE]

anyone got any thoughts on building a st st frame ,have seen a few but how safe is it?,is 316l the grade to go for?,ive made a few swingarms with st st but i would like to build a frame out of it,i know it distorts like fuck as well!,my swingarms were tig welded 316 st st.

[dracken1]

i make the odd thing out of ss but not a frame.
316 should be fine as it is a general purpose grade, in so much as it bends and welds ok, but don't quote me on that as far as a frame goes.

nitrogen purging is the thing to remember when welding ss tubes, as it ensures a safer weld

[Blackjack]

You can design your way round pretty much any problem in a frame. Even stupid things like deciding to build it out of toilet rolls.

The point is you need to understand whether the material you want to use is suitable for the frame you want to build.

Stainless as was rightly observed distorts like a bastard. So you need to allow generous clearances round things and fully weld the frame prior to adding any mounts for the motor and so on. Give some thought to welding the mounts on and finishing them to size after they are welded (weld it, then machine it is generally good advice).

As for the actual design of the frame a spindly rigid isn't really suited to stainless as they tend to flex and stainless tends to work harden. Not a good combination. Something similar to a Harris or a Spondon frame where the rigidity is inherent in the design would be better.

Thin Wall 316L doesn't seem overkeen on bending to me, might be OK in a mandrel bender, but it doesn't like compression benders, ever wonder why you can buy preformed 316L bends most places? Though apparently the "L" is a heat treatment so there may be other grades of 316 that bend better.

Not really my area of expertise, just some collected observations.

Not something I've ever done

[xjtriker666]

fill ya tube full ov sand then ya get very little crippled effect if any at all