Learn me: Bending 7/8” round steel (40 year old handlebars) with heat...

I have a pair of “buckhorn” handlebars that I want to bend into more of a “rabbit ear” shape.

Is there a cheap heat source I can buy that’ll give me enough heat to effect the bend? Plan is to pack with silica sand prior to heating. I can’t afford a set of tanks for a small job like this. And I’m not sure what the deal is with MAPP gas nowadays.

In reply to wheelsmithy :

Any actual help will be much appreciated.

While that was a bit tongue in cheek, what I was saying is that bonfires get pretty hot, and should be sufficient to bend 7/8" solid bar, if you dare. I have doubts about MAPP gas. 

Can you rent a set of tanks and a rose bud tip?  Or find someone that has it.  I don't know of another way.  I don't think MAP gas will get there.  You could try it, but that's some heavy steel.  On a Harley, it would be stainless.  Don't know what you're working on.

7/8 solid rod will bend cold (with leverage).

It appears you're packing tube with sand... heating is generally the wrong way to bend tube.

The "proper way" will vary depending on what tools you have and your skills.

A heavy table and some crude-ish homemade bending blocks can do it.

In reply to jamscal :

Oh yeah? You think I can/should bent sans heat? I have the physical ability to do it, I just assumed you’d need heat.

If you can pack with sand really well, it won't collapse too badly cold.  Heated tube bending is totally possible, but I'm here to tell you, it takes a bunch of care and practice to do it right.

Considering that they`re 7/8" bars, is there not a cheapo set from Bikemaster available?

Usually Bikemaster bars are like $20.00 a set on eBay.

ShawnG said:

Considering that they`re 7/8" bars, is there not a cheapo set from Bikemaster available?

Usually Bikemaster bars are like $20.00 a set on eBay.

No one seems to offer what I’m looking for. Something like these: 

Id gladly convert but I haven’t seen a solid, foolproof method that’s not too hack(y).

I dunno about bending the bar, but I do know that I am constantly surprised at the $20 benzomatic torch from the hardware store.

It can get just about everything I need to heat as hot as I need it. Yes, sometimes i have to be patient. But to me it beats having to keep oxy acetalene tanks around.

Getting a tubing bender is not overly expensive.  The 7/8" on the handlebars is likely OD, which means that 3/4 EMT conduit is about the same OD. (around 0.82 inches)  If you had a 3/4" EMT bender you could likely do it with some muscle.

Bending (or unbending) steel tube with heat is not easy.  You would have to make sure that every inch has the exact temperature you need to make the bend.  Too much heat in one spot and you don't have a curve, you have an angle.  It would take a very long time with Oxy/Acetylene to get the right amount of heat, and even then it would be very difficult to get it even.

Oldschool way i knew was to fill with sand first, to prevent collapse of the tube.

Do a search for 'old yoshimura way' and watch that video for the jist of the process either way. Dude have a nice approach most people could emulate in a home shop/garage/driveway. He uses a oxy/acy rosebud looks like, but I bet propane/oxy or even Mapp-lite would do the trick. On mobile or id post a link. 

Nugi said:

Oldschool way i knew was to fill with sand first, to prevent collapse of the tube.

Do a search for 'old yoshimura way' and watch that video for the jist of the process either way. Dude have a nice approach most people could emulate in a home shop/garage/driveway. He uses a oxy/acy rosebud looks like, but I bet propane/oxy or even Mapp-lite would do the trick. On mobile or id post a link. 

Yes, I mentioned filling  with sand in my first post. I also talked about the fact that I can’t afford the tanks etc to get that kind of heat.

I watched the video though. Outside my abilities at the moment for reasons listed above ($$$) but really cool to watch.

I needed to make a seat hoop for my wife's bike. it has wide "hips" so no off the shelf hoop would work and they didn't sell a bending die in the dia that I needed. So I made my own cheap bender. I think that it was 22mm tube, so close to what you are looking for.

I welded a bolt to one end, packed with playground sand and bent it cold.

I made a bender with plywood and scrap random crap I found in my garage. The only thing I had to buy was the router bit ($20).

In reply to Rusnak_322 :

Ok, that’s really freakin’ cool.

Put that in the “Show Us Something You Made” thread at once!

ebonyandivory said:

In reply to Rusnak_322 :

Ok, that’s really freakin’ cool.

Put that in the “Show Us Something You Made” thread at once!

^^^ I'm with E& I,  put it in the other thread. That was a lot of time consuming work to make everything to fabricate the tube.

Bending handlebars using crude techniques could lead to cracking at some point. I've seen waaaay too many unmodified production handlebars crack (owned a bicycle shop for 25 years) to even consider modifying a set other than cutting for width. It's a safety thing, I wouldn't risk it.

Maybe a local chassis shop can make you a set of custom bars if you bring them some tubing?

In reply to NOT A TA :

Hadn’t considered that to be honest. That’s a legitimate concern. Thanks for the heads up.