Bending tubes.

[claybear]

I was just curious if anyone had any good ideas on how to bend tubing to make a rigid rear end. I don't have a torch, and I don't have access to a bender. I had thought about cutting into the tubing about half way, bending then re-welding back together, but I'm unsure how safe that would be. Maybe with gusseting? I wouldn't be too worried about the top tubes since I'm planning on keeping the mid controls and that section of frame is behind where the bends would be, but the lower rails I'm unsure of. Any advice?

 

[gordonscott]

Any advice?

Ya, have a pro do it! Pretend your life depends on it

 

[swbill]

I was just curious if anyone had any good ideas on how to bend tubing to make a rigid rear end. I don't have a torch, and I don't have access to a bender. I had thought about cutting into the tubing about half way, bending then re-welding back together, but I'm unsure how safe that would be. Maybe with gusseting? I wouldn't be too worried about the top tubes since I'm planning on keeping the mid controls and that section of frame is behind where the bends would be, but the lower rails I'm unsure of. Any advice?

Really??? Cut the tube and weld it??? Imagine what that would look like not to mention how safe it WOULDN'T be. Sounds like TC bros hardtail would be good for you.

 

[mrpink]

I had thought about cutting into the tubing about half way, bending then re-welding back together, but I'm unsure how safe that would be.

That would be safe enough to get you all the way to the scene of the crash.

Get someone who has experience to help you.



p!nK

 

[PAhunter]

As far as fabrication advice goes there are many experienced fabricators here on the board. And if you saw some of their work (particularly Gordon Scotts) and craftsmanship you would know you are in the right hands advice wise.

From a newbies perspective who lives in the ass end of nowhere where services are limited and not really able to spend a bunch on a hardtail I can tell you the following.

By the time I found material and a bender and worked out how to make a jig etc plus not being able to weld to a standard I would trust my life to I found the cost was far exceding a TC Bros hardtail.

Though if you do want to persevere on your own hardtail I would at least have your bends done on a proper bender. Most steel or pipe suppliers can do this for you.
When I was considering doing my own hardtail I think they were going to charge me $5 a bend. Another option was a local tool rental place had a bender I could have rented for a week for $50.

 

[tonyc]

I agree with everyones posts. You should let a pro do it. But how do you think the pros learned to bend tubing? I think with plenty of research, practice,and safety observances I can tackle almost any thing. But again if you are not going into business why would you want to do only one example? This fabrication takes learned skills and in the long run will cost you much more to learn the right way as to having the work farmed out. Good luck Tony C

 

[mrpink]

But how do you think the pros learned to bend tubing?

They worked along side other, more experienced professionals.

Frame construction is not really a good "trial and error" candidate. The side effects of "errors" can often lead to severe bleeding or even death.



p!nK

 

[tonyc]

Mr. Pink That is exactly my point. To obtain this knowledge It will take time and money. The cost will be much more than having it done by a pro. I am a certified welder and do not do structural welds on any of my bikes because I have never done these welds.
TonyC

 

[mrpink]

Mr. Pink That is exactly my point. To obtain this knowledge It will take time and money. The cost will be much more than having it done by a pro. I am a certified welder and do not do structural welds on any of my bikes because I have never done these welds.
TonyC

Ahhh I see. When you said "let a pro do it" or "farm it out" I took that as just handing it over to someone else and learning nothing.

With your above post we are in 100% agreement.


p!nK

 

[claybear]

Thanks for all the advice guys, I was really just wanting to go the cheapest route, while at the same time being able to do my own work instead of letting someone else do it. I especially didn't want to buy a rear section pre made, cause to me it seems like it takes some of the fun out of building my own bike if you know what I mean.
Maybe I can see if my old boss at the machine shop will let me come in and use a bender for a couple minutes. Someone said that metal supply companies can do it? I guess that would work too if I can find one. Any ideas on what degree they should be bent at though?

 

[gordonscott]

Hi Claybear, Get a carpenters protractor, they have them at home depot or hardware store. You can use these to get close, bend a little under what you think you need and bring over to bike, check for fit and then bend a little more untill it's what you need. Here is a link to a homemade tail I did in my basement at home.... http://650rider.com/index.php?name=Forums&file=viewtopic&t=7357&postdays=0&postorder=asc&start=0 Hope this gives you a little help?

 

[Teebs]

Another option is to get some conduit, which is relatively cheap, and a conduit bender, mock up everything just the way you want it, then have someone do your bends and if you're new to welding, have the welding done too...

This way you have full control over the creative process and are still being safe. Way better than a TC Bros hardtail.

Too many brothers die because of other people's stupidity, I try to discourage riders from adding to the numbers unnecessarily.

I really respect that you want to do it yourself. That's the whole spirit of chopping. I hope you maintain that attitude and do absolutely as much as you can on your own, but no shame in letting a pro do it until you have enough experience under your belt and the right tools for the job.

 

[rustynail99]

Teebs that is a fantastic freakin idea! i think if i ever have any free time, i think i may make an entire frame from scratch out of conduit just to do it (of course i would never use it, just for the practice ) thanks for that. you are just an ASSHAT full of idea (pun indended )

 

[gggGary]

Do it! It's the back of a motorcycle not the front of an airplane. And lots of guys have welded their own airplane frames. If you do your own welds figure on inspecting them frequently. You might try a wanted to borrow or rent on craigslist. There have to be herds of benders out there sitting around not being used.

 

[Teebs]

lol, I'm an asshat full of something alright...

I seriously hope this helps some guys. It's an awesome way to do mock up.

I've seen guys use pvc pipe too. I really like the conduit because you can use it over and over again, it bends easily and once bent you can straighten the bends a little with just your hands. Also, it's extremely light and is slick to tack weld. The fumes aren't good for you though, so keep that in mind. You can weld it all together and it's strong enough to support a person's weight with a motor in it, so you can do a complete mock-up front to back, as long as you know your measurements are all going to be the same and taking the difference in diameter between tubing and conduit into consideration. Also, and for me this is a BIG also... you can usually find a LOT of conduit scrap on craigslist, or a scrap/salvage yard or wherever for dirt cheap or nothing at all.

I made a set of mock-up bars out of it for the xs I'm doing now, but damned if I know where they went or I'd post a pic... I think one of my nephews might have scabbed them for his bicycle.... luckily I have all the measurements written down in a notebook... not really sure where that is at the moment either...

 

[sgt sleazebag]

if you can weld and understand gusseting and triangulation you should be able to do it.every weld on my bike is fluxcore 120v.my downtube is stretched and thats all butt welds.i weigh 280 and ride hard as hell.do you trust yourself? let er buck!