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Author Topic: Tubing bender or roller for exhaust?  (Read 1378 times)

Offline ChopperCharles

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    • Modified Motorcycles by Chopper Charles
Tubing bender or roller for exhaust?
« on: Dec 29, 2017, 14:02:42 »
I'm looking to buy a tubing bender that can handle thin wall (16ga) steel and stainless steel tubing, 1.5" and 1.75" OD. I want to make a midpipe slip-on for my bike, and maybe make a handful of copies to sell on eBay to cover the costs of the bender and materials. I need to make one 8 degree bend and one 12 degree bend. Nothing off-the-shelf will work.


I've looked into the JD2 model 3 tubing bender. It's expensive ($310 + $300 per die set), and their customer service says it cannot do thinwall tubing without kinking it. I'm thinking it might be possible if I seal the tube ends and fill it with sand, but that's a lot of money to drop on a maybe.


Eastwood makes a similar bender, at a similar price, but does not list a lower limit to the wall thickness. Likely though, it will have similar problems.


That leaves the Harbor Freight tubing roller. It's $180, it comes with a 1.5" die, and 1.75" dies are available from SWAG for $220. People are making roll cages with this thing, and getting down to 7.5" diameter bends with enough time and effort. So it can make the right bends... and being a roller it's unlikely to kink even thinwall tubing. That's my theory at least.


All of these will also need a stand.


I'm leaning towards the tubing roller at the moment. I really need the ability to bend 1.75" exhaust tubing, but for the moment I could actually start a project that uses 1.5" exhaust tubing, just to test the roller. If it isn't suitable, I could in theory just return it and not be out any cash or any shipping. (I dunno if HF has a restocking fee, but I doubt it).


Honestly what I'd like is a bender that comes with an assload of dies and is suitable for both thinwall and thicker DOM tubing, so I could also make frame hoops and other parts. But I'm thinking that's not likely possible.


Any thoughts on this would be great!


Charles.

Offline SONIC.

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Re: Tubing bender or roller for exhaust?
« Reply #1 on: Dec 29, 2017, 14:07:14 »
I've got a JD2.
It's great for thicker tube, but thin wall exhaust it will not do without kinks.
It's more for roll cages and frames

Offline themotoworks

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Re: Tubing bender or roller for exhaust?
« Reply #2 on: Dec 29, 2017, 14:17:12 »
i also have a jd-2, it's not going to handle tube that thin, tubing like that is bent using a mandrel, using an unsupported bend die will kink it or flatten it out.  other methods that can be used for a small angle bend like that are sand bending, or low melt alloy bending, to sand bend, you need to weld on a large nut on one end of the tube (3/4-10 or 1-8 or so), cap the other, fill with sand, tap the side with a small hammer, keep filling, until the sand settles, stuff in some paper towel and then screw a bolt into the nut, heat the bend area with a rosebud acetylene head and bend, a bend that small shouldn't take much practice, doing something like a 90 degree with 3.5 clr takes some skill.  low melt alloy would need to be bent cold using a supporting die, but for that you could probably use a piece of schedule 80 pipe 4" or so in diameter

Offline doc_rot

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Re: Tubing bender or roller for exhaust?
« Reply #3 on: Dec 29, 2017, 18:45:49 »
why don't you just buy pre bent  mandrel pieces and cut them to the degree you want?
« Last Edit: Dec 29, 2017, 18:48:38 by doc_rot »

Offline ChopperCharles

  • Posts: 72
    • Modified Motorcycles by Chopper Charles
Re: Tubing bender or roller for exhaust?
« Reply #4 on: Dec 29, 2017, 19:14:54 »
Because that won't look very nice, and it's a lot of fitting and labor and the bends themselves are expensive. If I want to make 30 of these, I'd rather bend 30 tubes than cut and weld 60 tubes. And they'd look nice.

Charles.

Offline hooligan998

  • Posts: 238
Re: Tubing bender or roller for exhaust?
« Reply #5 on: Dec 30, 2017, 00:54:21 »
A welded exhaust won't look nice?  Depends on how it done.  All the cool kids are doing it.  Ok, yea, labor, but if it's worth doing, you may as well do it right.

Offline DesmoDog

  • Posts: 256
Re: Tubing bender or roller for exhaust?
« Reply #6 on: Dec 30, 2017, 02:27:46 »
I'm looking to buy a tubing bender that can handle thin wall (16ga) steel and stainless steel tubing, 1.5" and 1.75" OD. I want to make a midpipe slip-on for my bike, and maybe make a handful of copies to sell on eBay to cover the costs of the bender and materials. I need to make one 8 degree bend and one 12 degree bend. Nothing off-the-shelf will work.

I've looked into the JD2 model 3 tubing bender. It's expensive ($310 + $300 per die set), and their customer service says it cannot do thinwall tubing without kinking it. I'm thinking it might be possible if I seal the tube ends and fill it with sand, but that's a lot of money to drop on a maybe.

Eastwood makes a similar bender, at a similar price, but does not list a lower limit to the wall thickness. Likely though, it will have similar problems.

That leaves the Harbor Freight tubing roller. It's $180, it comes with a 1.5" die, and 1.75" dies are available from SWAG for $220. People are making roll cages with this thing, and getting down to 7.5" diameter bends with enough time and effort. So it can make the right bends... and being a roller it's unlikely to kink even thinwall tubing. That's my theory at least.

Honestly what I'd like is a bender that comes with an assload of dies and is suitable for both thinwall and thicker DOM tubing, so I could also make frame hoops and other parts. But I'm thinking that's not likely possible.

There is no simple bender that will bend thinwall tubing without deforming it. That's why mandrel benders exist.

I have no hands on experience with tubing rollers but it seems to me it would be a complete pain to get any sort of repeatable shape out one. I have used tubing benders before, it's hard enough to use those "freehand" let alone a roller. Having no idea what the shape of this midpipe is I can only assume the two bends are on different planes. How accurately do you think you can do that, by hand, on a roller? If the centers of the bends are 1/4" off will the pipe still fit? If the rotation is 1 degree off will the pipe still fit? Even with six figure CNC mandrel benders we have to do trials to dial in the programing on pipes.

A 7.5" radius bend in a 1.75" OD pipe is HUGE. I have a hard time believing that will work on a midpipe for a motorcycle but the bends are shallow so maybe? You want to be able to do half that at least. There will be a minimum distance between bends, have you figured out what the distance between the tangents will be on your part and if that is something you can do on a $200 roller? 7.5" radius bends need more distance between them than 3.5" radius bends.

You absolutely can fill the pipe and avoid crushing it. If you can't try again until you can. Some use sand, some use steel shot, I've even seen ice being used. That said, the bends you are trying aren't major. You might get away with letting things do what they're going to do.

If you're serious about this, buy the JD2. Bending exhausts on it will be a pain in the ass but it will still work better than anything from HF once you figure out how to make it work.

IMHO you're opening yourself up to a world of hurt if you expect to bend up repeatable shapes by hand to sell to others. Make sure you have a nice gauge to check the parts before you send them out.

Follow doc_rot's advice. Use pre-bent pieces and do a one off. Forget about making 30 of them, it will take ten times longer than you imagine and the scrap rate will be huge.
« Last Edit: Dec 30, 2017, 02:30:49 by DesmoDog »

Offline ChopperCharles

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    • Modified Motorcycles by Chopper Charles
Re: Tubing bender or roller for exhaust?
« Reply #7 on: Dec 30, 2017, 03:55:19 »
Actually, the two different bends are for two different systems. One for dual 1.5" pipes, one for a single 1.75" pipe. The 1.75" pipe is the important one. If I can reproduce, it's essentially a single-bend midpipe that would allow one to use any 1.75" OD muffler on stock headers, saving owners from having to buy a $750 slip-on. EMGO reverse cone and a midpipe and call it done.

But I see your point. Maybe it is futile to try this.

Charles.

Offline DesmoDog

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Re: Tubing bender or roller for exhaust?
« Reply #8 on: Dec 30, 2017, 19:41:11 »
Ahh... single bend? That's a different story. I'd still want a bender and not a roller though, but that may just be me not being familiar with them.

Would you have to size one of the ends? Those manual pipe expanders are good for making damaged ends round again but I wouldn't want to have to increase the pipe by a metal thickness with one. Not the one I have anyway. Maybe with an omact wrench? Haven't tried that yet. (I have access to real pipe sizers, no need to struggle at home with manual stuff!)

Offline doc_rot

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Re: Tubing bender or roller for exhaust?
« Reply #9 on: Dec 30, 2017, 21:37:46 »
if you really need 30 pieces call up a place selling mandrel bends and I bet they would do a custom bend for you for not much additional cost per item.