Landracing Forum
Tech Information => Technical Discussion => Topic started by: donpearsall on May 03, 2016, 10:23:44 AM
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I need to put a large radius bend on some 1"x3" x .120 rectangular steel tubing for my motorcycle frame project. I bought a Harbor Freight tubing roller thinking that there were dies available for that size tubing, but now I can't find any. There are some dies available from SWAG Off road, but those bend on the narrow side and not on the wide side. I would estimate the bend to be about 10' radius.
So does anyone have any ideas on how to bend this tubing without kinking it? I have a shop press and was thinking about using that but have not tried it yet.
Thanks
Don
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we routinely roll rectanglar tubing at work, but it is tricky. Kinking isn't the only worry, collapsing the inside wall is a big problem as well. We have a large, and I do mean large, can handle sheet up to 6 feet wide and has 24" rollers, rolling machine at work. I've yet to see a result on square tubing that was exactly what we wanted, even when we roll it in small steps. It's also heavily dependant on where the seam of the tube is. We sometimes get tubing with the seam on the short side and that's a disaster every single goddamn time we try to roll that crap. It'll split, people will swear, it's bad joojoo. When the seam is on the long side it's not a lot better. If you roll it with the seam on the outside of the radius, it can split, if you roll with the seam on the inside of the radius it'll kink. On 2x4 box we are lucky to get good results on anything smaller than like a 40" radius.
What we have done in the past is roll with the seam to the inside of the radius and just let the inside collapse inward. We then roll some plate to a matching radius and seam weld it to the tubing to cover the collapsed area. Pretty cheese dick stuff.
Pretty much we just avoid doing it. It makes us angry and irritable.
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It's a lot less heartache to just fab it out of flat sheet. :-P :cry:
Sid.
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They guy I used that bent 76 x 38 x 3mm had CNC equipment and he also battled. The top section does get a slightly domed form sometimes. Not an easy or DIY deal.
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Don, You might contact Art Morrison Ent. in Fife, Wa. I believe they have non-kink mandrals for 2"x3" which means You would have to split it and reweld the tubing but that part would be easy to do. Bob
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You could fill with lead or sand before bending .
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Fill it with wax. Make some rollers for your Harbor Freight roller.
Doug :cheers: :cheers: :cheers:
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Back in the sixties I had a roll bar bent by a outfit in Portland called Albina Pipe. What they did is filled the tubing with what appeared to be roofing tar used for mopping "hot" tar roofs.
How do I know this? Because I had to use a torch to get the crap out of the joints before I welded it.................. :-P :-P :-P
O.R.B., out....................................
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Hmmmm, https://www.albinaco.com/steel-bending-profiles/square-and-rectangular-tube (https://www.albinaco.com/steel-bending-profiles/square-and-rectangular-tube)
Mike
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Don, I suggest you send it to a shop that is expert on tubing fab.
I used to use Master Metal Products in San Jose, CA. There are
others in the San Francisco Bay Area (such as Superior Tube),
but if you are near Seattle, I assume there are some capable
shops up there who have done great work for the aircraft industry.
Don't expect it for a low price, though. It's like that old sign I used
to see in a Shakey's Pizza Parlor:
Quality is like buying oats.
If you want nice, clean, fresh oats, you have to pay a fair price.
If, however, you can be satisfied with oats that have already gone
through the horse, that comes a little cheaper.
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Depending on the radius, how many pieces and what it's worth to you will probably determine what to do.
Crush rolling is probably cheapest, (caves in the inside of tubing). Hot forming, (feeding through a pass through furnace, which is easy to make)
or hand bending like this guy. https://www.youtube.com/watch?v=VO-OatK4HzI
I've used all methods, none of it is much fun, especially if you have to please a customer.
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I really like the way the guy bends the tubing and it really comes out nice but first you need a really "bitchen" fab table like he has!!!
Rex
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Don, pack it tightly with wet sand. Freeze it. Bend it.
I want to check out your progress :cheers:
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Is round tubing out of the question?
Regards, Neil Tucson, AZ
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I need to put a large radius bend on some 1"x3" x .120 rectangular steel tubing for my motorcycle frame project. I bought a Harbor Freight tubing roller thinking that there were dies available for that size tubing, but now I can't find any. There are some dies available from SWAG Off road, but those bend on the narrow side and not on the wide side. I would estimate the bend to be about 10' radius.
So does anyone have any ideas on how to bend this tubing without kinking it? I have a shop press and was thinking about using that but have not tried it yet.
Thanks
Don
Don, just to clarify are you trying to bend this the hard way or the easy way, in other words are you trying to bend the 1" section or the 3" section. I've had some success doing this sort of bending with my Hossfeld converted to a roll bender.
Pete
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Thanks for all the suggestions everyone!
Pete - I want to roll it the easy way. Just put a smooth large radius bend in it. Since it is structural I was hoping to do it without kinking or caving.
Neil - if I can't find a good way to bend the rectangular tubing, I will have to use round tubing.
Don
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Art Morrison is near you in Fife. They bend rectangular tubing for their chassis business. They list 90 degree bends in 2 x 4 tube pieces in their catalog. Perhaps they might bend it for you.
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If you are using thin wall tubing, 049 or 062, then packing it with sand (weld a cap on one end, fill with clean sand, tamp the sand so it is completely full then weld a cap on the other end) should work as bending in the "easy" direction really should not take much force. You need some sort of bend block (pattern) to bend it around, like the guy in the vid. You may also want to apply some "blue wrench" to the 1 inch sides during bending as this will make them form easier and cause less stress in the long sides which will help prevent them from being miss formed. BTW what is the radius the you are looking for??
Rex
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Little late in a reply here, but I also recommend Art Morrison. I had some 2x4 bent up (easy way) in large U-shape, to make the flatbed on my 49 Ford COE. I think it is around 8-inch radius on the bends, but they nailed it dead on for the total width, and dead on for the 90 degrees at each bend. I specifically wanted rounded corners and not mitered, since the rest of the truck body is all rounded. This was before Art Morrison was offering stock 90 degree bends, but I wanted it one-piece U-bends for the front and back of the bed to be one length. Biggest hassle was the 2 U-bends had to go truck freight due to size, shipping was a big portion of the cost. Art Morrison's price for the actual bending was quite reasonable. The bends are madrel net and all smooth. No kinks, no crushing inner wall, no excessive die marks on outside, just a real nice smooth bend.
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Sharper bends can be made by cutting a bunch of pie shaped slices out of the inside three walls and leaving the outside wall intact, then bending the tube till the gaps close, then welding the seams.
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Sharper bends can be made by cutting a bunch of pie shaped slices out of the inside three walls and leaving the outside wall intact, then bending the tube till the gaps close, then welding the seams.
That`s how I "bend" rec. tube for frame kick-ups over the axle. just don`t grind the welds flush...Inspectors will have a stroke. :cheers: