Manky Monkey Motors

Hi Guys,
can anyone tell me where I can buy really good tube bender guides.
A mate has loaned me a tube bender (he's not used it for ages and says that I can look after it for as long as I need too and that if he does need it he will bring it back!!!!!!!! COOL) but the guides do not fit the tube exactly and the sides are a bit shallo, so the tube creases.
Any ideas anyone.
Thanks
Take care ride safe have fun.
Keith

what type/size tube & make/modelbender are you using?

We've got a Clark's bender, (about 80 quid from Machine Mart), & use 4mm wall thickness ERW tubing. Seems to bend with no problem, though the 1 1/2" bore  I use for top tubes tends to leave two small indentations where the rollers have been if I pull it through more than 45 degrees.

Hi Guys,
I'm using a clark bender, and 40mm tube with a wall thickness of 4mm.
Tha problem that I have is that the dies seem to be just slightly too large and not deep enough so that the tube starts to collapse. Thats why i'm thinking that more accurately made dies with deeper walls might help.
Thanks
Take care ride safe have fun
Keith

Hmm, the ERW's not the best quality tube in the World -it does what we want of it, but it's only a nominal size. It varies slightly from one batch to the next. Never had a problem bending it though. I once tried some other tube & had to pack the die with duct tape to make it a tighter fit. Could try that. The dies are shallow though & only come up to the centre line of the tube. As I said, it's never been a problem so not sure what to suggest.
Anyone else?

Where abouts are you putting the seam inside the metal? Is it facing the die, or outwards?

Hello all,
reliantman asked where I position the seam, it obviously makes a difference.
The question is ...where should the seam be?
Thanks to all for the help so far.
Take care ride safe have fun.
Keith

Keith.
I have dropped myself in it now, as I was going to come straight back and tell you which way, but I can't remember myself. I think the bead has to be against the die, but I am not 100% sure.
I have been on the net all afternoon, and cannot find the answer yet, but I am sure it is there.

Suggest cutting two "Saddles" from next size up and place ontop of the tube your going to bend and directly under the rollers. "Saddle" = a half section of tube about 50mm long. This helps me when I have that problem.

Hi Guys
Had a go at bending some more tube, tried with seam up, seam down and seam at the side. Its still not happening.
The top goes flat in section and the bottom creases really badly, even with a bend of 45 degrees from straight. The problem is not ocuring where the tube meets the rollers but on the bend itself.
Any other suggestions will be most welcome.
Thanks again,
Keith.
Take care ride safe have fun.

You sure you're using 4mm thick tube? Shouldn't be folding up like you describe. If it creases that easily I'd be a little worried about it's strength for frame building.
Where have you got the rollers positioned? They're adjustable on ours -half a dozen hole positions. We usually use the middle one. Personally I've never worried about the seam position. Can't say I've noticed it's made a difference to the bends, but I guess facing into the die would be least stressed.
I suspect you're not using the same kind of tube we are. How about warming it with a blow lamp before bending?

Mostly agree with above. You could try packing it with wet sand, or if you had enough, melt some lead and pour it down the tube, then heat it up after you have finished. The sand is supposed to be better though.

Plumbers' merchants sell a long coil spring for putting inside copper pipe when you bend it to stop it collapsing, in much the same way as the sand works.

Keith, exactly what tube are you using??  As for the "welded seam position".... I often produce "compound" bends (I think thats what Manky calls them) which means that they will curve different ways along the length of the tube. Although I may start with the seam facing down into the former, when I move tube along for the next bend it maybe facing up or to the side. I have never had a problem with this. I really think you need to look at exactly what specification your tube is. Dont despair, we''ll help you through this ::) ;D

We will?
Oh right, we will.  ;)

Thanks for the replies I do appreciate it.
Can anyone tell me what they use for frames etc.
I'm using 40mm dia 4mm wall ERW. Is there anything better but not needing a morgage to buy?
Thanks again
Keith
Take care ride safe have fun.

 My trike frame tubing is BS1387(?) Gas Barrel or Steam/Water pipe (they dont call it tube for some reason), made by Corus, available in light/medium/heavy wall thickness. I have never had a problem with this and I use the "medium" which has wall thickness of 3 to 4mm and is available in various nominal "bore" sizes. I find the 1 inch nominal bore suits the trike frames ive built and gives an o/d (outside diameter) of 33 to 34mm. It seems the bore sizes are always in imperial but wall and length being in metric. This pipe used to be painted black with a blue band although now seems to be "red oxide primer". When "plug & butt welding" the 1inch bore I find the 3/4inch bore is a tight fit inside, this only works with wall thicknesses of same size, ie: medium/medium. Hope this helps :)

As for the "welded seam position".... I often produce "compound" bends (I think thats what Manky calls them) which means that they will curve different ways along the length of the tube. Although I may start with the seam facing down into the former, when I move tube along for the next bend it maybe facing up or to the side. I have never had a problem with this





I often wondered about that. When I was learning to weld the instructor told me about the seam thing, but you're right about the different angles.

Yup, I'm using the same stuff as Pete. 1" bore for the main frame tubing with 1 1/2" for the top tube. Bought for about 2 quid a foot, (comes in 4 metre lengths), from my local branch of Pipe & Tube.

Thanks guys,
well i'm off to the steel suppliers in the next day or two. I'll give the steam/water tube a go and keep you posted.
Thanks again
Keith.
take care ride safe have fun.

I've been using ERW, (electrical resistance welded) tube for over ten years now. The subject of tube quality's a regular debate on various bike forums -the argument being that seamed tube is more prone to bursting open under pressure or failing along the seam through fatigue. Go for the more expensive CDS, (cold drawn seamless), if it gives you peace of mind -after all, it's you who's got to ride the finished machine, but I can honestly say I've never had a problem with ERW or heard of anyone else doing so. Chris Ireland, ("Desperate Dan"), mentioned it on his Brit Chopper forum only a couple of days ago. If it's good enough for him, it's good enough for me. If it's in a properly thought out, well triangulated design, it's as strong as you'll ever need.
I dug out some off-cuts of ERW while I was in Ska Man's garage this evening.
Ours is in the newer red oxide finish, which is much nicer to work with than the older black stuff -seems to bend & weld much cleaner.
The bulk of our frames is done in 33.7mm outside diameter tube, (roughly 1" bore), which has the identification "Corus Install EN10255  33.7" printed on it.
The 1 1/2" bore we use for top tubes is 48mm O.D
ERW's presumably a softer, more pliable grade than the tube you've currently got.

I had exactly the same sort of flak from some members when I mentioned what I used as well.
Recently I met a guy in Bridgend, who has been building VW frames for twelve years. He has put several complete trikes through the MSVA and he uses 27mm ID, 3.2mm wall mild steel pipe, which is reasonably cheap.
I got a quote of £16 a length from a place in Cardiff docks, so I will probably be getting some of that next time.

Hey Guys
the pipe bending saga is over!!!!!!!! Went to the steel shop this morning, took the two formers with me and got some tube that was a tight fit. Rushed home full of excitement and set up the pipe bender. I placed the rollers where I needed then, put the tube in and with some trepidation I began to pump the handle. Nothing happened..... then I closed the valve!!!!!!!!! I began to pump and the tube began to bend, I continued pumping, the tube continued bending. I pumped for all I was worth :) The tube offered some token resistance but finally succumed to my will, well would'nt you with a 12 tonne jack up you!!!!! >:(
I released the pressure ::) and had to take a hammer to the tube to get it out of the fromer....a good fit. Then I realised that i had not put a 'saddle' under the rollers(nothing a bit of work :'( won't fix>
The tube had bent as I wanted with NO distortion except where the rollers are.
In short... Thanks for the advice given by everyone.
Keith

Keith.
Thats brill. Now you just have to practice with it.

 http://www.pirate4x4.com/tech/bendin_tube/index.html

The link above is for a place in the states that makes roll cages. They use an expensive bender, but the site shows you how to measure the metal.

Thanks Doug  I had a look it's a Good site
regards
Keith

Another tube mangler is born  ;D
There'll be no stopping him now!

Yes there will, the wife will probably stop me when there's some man's work to do in the house..... must'nt complain too much as she may read this and i'm scared of her!!!!!!

That's what garages are for -your own little macho domain where you're lord of all you survey -& somewhere to hide from the missus.

Oh is that why Mike complains that he can't get his car in the garage cos of my trike and bikes?



*wears innocent face*

 ;D

I'm looking at getting a Clarkes pipe bender myself, can I bend exhausts on it as well frame tubing?

Haven't tried. I guess so, though you'd probably have to space the rollers out to their furthest setting, to give as gradual a bend as possible, which would hopefully stop the tube kinking. It'd be very easy to crush exhaust tube so you'd need to practice & see just how much pressure you can put on it.
Try it & let us know!

I tried a bit of exhaust pipe in mine, it destroyed it  :o need to use either a spring shoved up it or fill with sand/lead.

There you go. The voice of experience. Nothing high tech about us. Try it & see is our motto!