tube bending / rolling ? and profile question

[dean_petley]

sorry if its in the wrong spot i figgered you can go wrong in general

ok i have two questions relating to each other
i have built my chassis it is a set width 1550mm and length 2400mm to late for change now

1 my plan is to use 25 x 25 mm box section to from the profile of the side of my TD then weld that to my chassis brace it then sheet it from there but i no longer have to tools to roll the box my self after work closed down now the profile i have decided on is two sectioned eclipse but every shop i have gone to tells me its to hard
so i was wondering if there was any way to bend roll the profile i wont without the tooling

2 failing that i have redrawn the profile and made it from radiousses this will make it easy for the shops to do the work but it limits the room i was saving for a gallie meaning it might not be worth wild making a rear hatch if i dont have a gallie so i am after a quick poll drawing on the left or drawing on the right the one on the right has two options the top profile or the lower profile



thanks for any input

[corncountry]

Dean
I have built 2 tears with 1 inch X 16 gage steel box tube. I did the roll, cut and weld method. I built a roller and rolled shorter lengths of tube and welded them together. The profile was drawn on the shop floor and the sections of tube were matched to the profile.
There are some pictures of my build in my album. Good luck with your build. I think the metal framework is much lighter than wood.

Jim

[alaska teardrop]

Dean
I have built 2 tears with 1 inch X 16 gage steel box tube. I did the roll, cut and weld method. I built a roller and rolled shorter lengths of tube and welded them together. The profile was drawn on the shop floor and the sections of tube were matched to the profile.
There are some pictures of my build in my album. Good luck with your build. I think the metal framework is much lighter than wood.

Jim

Hi Jim,

I'd be interested to see a picture of your homemade roller if you have one.

Also, can you adjust the radius as it bends?

Thanks, Fred

[alaska teardrop]

Dean, In order to keep your original profile, another possibility is using a torch with a rosebud tip. Lay out the profile on a full size welding table, temporarily weld a jig of steel flat bar and carefully bend & clamp the tubing to the jig.

Examples:

Fred

[Dale M.]

You can also cold bent it with a plywood "buck" ... Same concept as bending "jig" above by taking apiece of plywood and laying out radius's and using 2x4 blocks to form shape, you can cold bend it to match, takes a lot of "GRUNT", hammering, large tools for leverage and its unwieldy and awkward.... You can use heat but after a while "buck" may become crispy, but if you only have two bends (sides) and you keep hose handy to douse any smoldering or flames... You can do it....Its just a miserable way without heat...

Dale

[KCStudly]

There was a build on here where they used a much larger piece of tube kind of like central spine, rather than corner edges, but the idea was the same.

Rather than cold bending he made a bunch of slicing cuts thru three sides, like kerfs or pie cuts, making it easier to form the uncut side. Then he welded all of the slits up on three sides.

Lots of cutting, lots of welding, and lots of grinding, but it is an option. Just throwing it out there as an option, but if it was me, I would try to form it.

[corncountry]

Dean
I have built 2 tears with 1 inch X 16 gage steel box tube. I did the roll, cut and weld method. I built a roller and rolled shorter lengths of tube and welded them together. The profile was drawn on the shop floor and the sections of tube were matched to the profile.
There are some pictures of my build in my album. Good luck with your build. I think the metal framework is much lighter than wood.

Jim

Hi Jim,

I'd be interested to see a picture of your homemade roller if you have one.

Also, can you adjust the radius as it bends?

Thanks, Fred

Hi Fred
There is one picture of my roller on page 5 of my album. I used portapower to put preasure on the top roller. It is powered with a motor and a gear box. You can change the radius as it rolls. If you get the radius too tight in some spot it is easy to bend it back by hand.

Jim

[MtnDon]

Harbor Freight sells a cheaply made Chinese tubing roller, but it only comes with dies for round tubing. I have seen an online vendor that sells assorted dies for square tubing for the HF machine, Swag Offroad. Their rollers cost as much per size set as the HF machine! The rollers can also be machined by any competent machinist. My son has made some. No, he does not sell them. However they do work and if you look at the investment in the machine and a set or two of rollers as just being another useful cool tool you can justify the cost to yourself. Swag also sells a tubing roller.

Nice metal work corncountry... I had not seen your handiwork before. Your roller looks sturdy.

[dean_petley]

thanks for all the replys
i dont have access to most of what was mentioned above due to work closing down but i did have a brain wave as far as using a bearing press with a few small modifications i think i can make it work to do what i need if not i have got the number of a mobile bloke who can roll the tube to what i need but will cost $ 250

i will have a play this afternoon thank you very much

[GerryS]

Depends how tight of a bend you need, but pipe can be safely bent if packed tightly with sand, then bent over a form...I've seen it done, but not done it myself...

[MtnDon]

Depends how tight of a bend you need, but pipe can be safely bent if packed tightly with sand, then bent over a form...I've seen it done, but not done it myself...

To do that you really need to weld a cap on one end, fill and pack the tube with dry sand and weld a cap on the other end first. W/o the caps the sand shifts. We built a few motorcycle frames that way back in the 60's. Some torch heat makes it easier.

[KCStudly]

I too, was thinking that the caps are necessary. With the torch heat dry sand is probably better, but I always thought that the key to cold forming was to use damp sand so that it packed better. I've also heard of filling tubing with water and freezing it before forming, but have not tried it myself (sounds less practical for bigger stuff).

It is my understanding that the sand method is how they form the very large radii in submarine fat line towed array storage tubes. Some place down in Texas does it (they have lots of pipe expertise in oil country). 10's of feet of something like 5 inch CuNi tubing snaking its way gracefully thru ballast tanks, mud rooms and stern fin structure. If I tell you any more I would have to kill you.

When a dedicated mandrel is too costly or impractical, sand makes a nice flexible yet relatively incompressible media.

I would be careful trying to press it in a bearing press without rollers or forms that have side support. You may (likely will) tend to crush and/or kink the tube rather than bend it gradually.

[dean_petley]

i had a play with the press other than the fact that it died after three compressions it pinched the tube to noticbly for me

i was thinking i have an old 15 inch steel rim laying around i might weld a bar across the rim lips then then insert the tube between the bar and the rim center and press down then simply move the tube further in and repeat untill i get the radius then ill do the other or i might do both at the same time with sand and caps

or i just found this

http://www.paramountbrowns.com.au/index ... er-bender/

[rand_98201]

Did I see above you mention there was a mobile guy who would come out and do the bend/rolling for you for 250$ ? man to me thats a no brainer.I would most definitely have him do that if you could.I know its easy for me to say since its not my money,lol.

[dean_petley]

as it turns out he needs three phase power to do the rolling something thing that i don't have access to sadly and the roller i bought was $309 delivered to my door and i get to keep it for next time