what kind of tube to weld frames?

[honestherman]

Braze VS Weld. Does anyone Braze a top tube in or just weld. What will work better and easier with Normal Riding. What are the limits of both?

 

[order99]

I braze tubing-but only because:

-I can't melt a hole in the tube with over-brazing
-MAAP gas is cheap and I am very poor
- As a result of the above, I have more experience with bronze rod than welding

Having said that, i'd use lugs whenever possible on load-bearing joints so the flowing bronze has as much surface grip as possible. Since I am so often cash-challenged, I do the next best thing-use extra tubing, grind and file an extra, extra-deep fishmouth and braze away at the sides, then gently peen the overhang flat across the other tube and braze that. I can always file it clean later, but if I don't see bronze literally mixed into and swirling in my freshly-ground and cleaned joint, I get nervous...i'm trusting 215 lbs plus cargo to these joints!

Oh, and if you don't mind an Industrial look to your top bar, you can take a small section of tubing, make a '+' shaped cut into it and bend it into a 'half-lug' to cover and reinforce an already-brazed joint...it adds a tiny bit of weight, but the industrial wheelbarrow I finished last September with these techniques now routinely carries 600+ lbs of equipment for the landscaping business I sold it to (strong boys those landscapers...).

 

[Henry Sanchez]

looks like I'm crawling around fine. Thanks for the advice, Luke. Don't want to overwhelm myself just yet.


Here's some practice TIG welds for my first frame build.


tube roller is ready and waiting. Now I just need to school myself with more practice welds and dimensions and dos and donts.



any other tips that a rookie frame builder might overlook? Like dimensions? chain clearance? Any rules of thumb I need to know?

 

[Henry Sanchez]

I have widened bottom brackets and crank axles in the past to suit wider rims, and will be happy to help with that if you get to it, but better to stay with known parts for your first couple of builds!

Luke.

I gotta ask, why not make your own BB and head tubes? Is the tap expensive? Is the little step in the head tube hard to make right?

 

[Bicycle808]

You need neither steps nor threads, really...

 

[LukeTheJoker]

I gotta ask, why not make your own BB and head tubes? Is the tap expensive? Is the little step in the head tube hard to make right?

I am just cheap! If you are using 3 piece bottom brackets you will need a left and a right hand tap, I have found that a particular size of fence pipe can be used for headtubes, but you still need to match your fork tube, fork tubes can be made easily too, the taps are not too expensive if you know where to look...

Luke.

 

[Bicycle808]

For the fork steerer, you can use a 1x24tpi die; usually you can get'm for about $30 USD. If you get the PArk Tool version for about $130, it has a mechanism to help you get the threads cut perfectly square... but if you're careful, you can get it square with the cheaper die.

 

[Henry Sanchez]

thanks guys. I want the head tubes that would allow head sets and those beefy forks. Will look into the taps. Maybe for this next build I can just get another Occ Schwinn to snag the head tube and BB and make a bigger chopper frame and use the rims/tires/forks and try to work in the chain/seat stays into the design. It would be less overwhelming and cheap...and my wife loves the word cheap.

 

[Bicycle808]

Tell me what headset/fork you wanna use, and i can help.

 

[Henry Sanchez]

I am just cheap! If you are using 3 piece bottom brackets you will need a left and a right hand tap, I have found that a particular size of fence pipe can be used for headtubes, but you still need to match your fork tube, fork tubes can be made easily too, the taps are not too expensive if you know where to look...

Luke.

I wasn't aware of how different head tubes are. I just recall my occ schwinn had a head set and a lip inside of the head tube in which I think the head set rested on. I could be wrong. I can see how it's probably smart to get your fork tube first for the length. So is the thread less head tube with the lip a common thing?

 

[sensor]

Just been reamed out. You can get tubing that is D.O.M. so no weld to deal with, as long as you know the headset O.D.(or bottom bracket) just get tubing with the same I.D.
You can also buy head tube and bottom brackets(specifically made just for bikes) for pretty cheap new if you want. I just pull the micrometer and head to the steel shop myself. No 2 weeks shipping that way.

 

[Henry Sanchez]

Tell me what headset/fork you wanna use, and i can help.

You need neither steps nor threads, really...

something like this. It's listed as Cruiser Bike Chopper Triple tree. Looks like I can have fat 4" tires with these and the head tube can be any size in length due to the clamps changing the steering tube length? Anywho, the down tube, seat tube, and top tube will be 1.25" so I'm hoping the head tube can be 1.25" and so that way I can weld them all on the floor. I think that's the route according to some good advice on this site. Would these forks work with a 1.25"? So would I just cut out the length and add my head set and am good to go?

http://www.ebay.com/itm/CRUISER-BIKE-CHOPPER-TRIPL-TREE-28-BIKE-FORKS-1-threaded/280867563410?_trksid=p2047675.c100005.m1851&_trkparms=aid=222007&algo=SIC.MBE&ao=1&asc=29905&meid=eec5ada2fdf74e6491ed8f388c03d3fd&pid=100005&rk=3&rkt=6&mehot=ag&sd=281400906642&rt=nc

 

[Bicycle808]

I'm afraid that 1.25" OD tubing would have to have some dangerously thin walls to accommodate even the narrowest JIS 1" headsets. You could find some 4130 tubing in 1.25"/20gauge but the walls would be .035" thick! I'd worry about that failing; it's less than a mm thick.

You could run 13gauge 1.375" (inch'n three eighths) tubing and run an ISO sized 1" headset (newer-school road/mtb/miniBMX size; got 30.2mm OD cups and a 26.4mm crown race) with minimal prepping to the headtube... but yeah, you'd probably want to build a jig for that; it would obviously not lay flat on the floor with the smaller main-tubes.