GTAW Chromoly bike frame....any advice, FILLER? TRICKS?

[Johnson]

I just ordered a tube set of double butted chromoly tubes for a bike I'm going to build. I have heard that 309L is ok, but some say use 70s6. Any bike builder out there with tricks or ideas that have made thin wall CrMo welding turn out nice? Thanks

[Rambozo]

I just ordered a tube set of double butted chromoly tubes for a bike I'm going to build. I have heard that 309L is ok, but some say use 70s6. Any bike builder out there with tricks or ideas that have made thin wall CrMo welding turn out nice? Thanks

Perfect timing.

[Tanh]

Nice! I was waiting for this one too. Now all that's needed is a way to cut and fit up the tubes. Gives me a great idea for a bike trailer as a project for the summer.

[Rambozo]

Nice! I was waiting for this one too. Now all that's needed is a way to cut and fit up the tubes. Gives me a great idea for a bike trailer as a project for the summer.

Try this for a neat way to make the fishmouth joints with a paper template.

http://metalgeek.com/static/cope_custom.pcgi

[Tanh]

Wow. Didn't expect to get an answer till daybreak. It's 1:30am here and I'm in the shop. It's a slow night so surfing takes up a lot of the time.

That's great idea, thanks for the link. I'm just wondering how one would cut the pattern once printed out. I've been tossing around the idea of a hole saw on a drill. Then there's not much use for the pattern anyways though.

[Rambozo]

Wow. Didn't expect to get an answer till daybreak. It's 1:30am here and I'm in the shop. It's a slow night so surfing takes up a lot of the time.

That's great idea, thanks for the link. I'm just wondering how one would cut the pattern once printed out. I've been tossing around the idea of a hole saw on a drill. Then there's not much use for the pattern anyways though.

There are a lot of tubing notchers that use hole saws. Others use a punch and die. But the paper and die grinder will also work. With thin wall tubing, you can even make pretty good time with just a rat tail file.

[zank]

Try this for a neat way to make the fishmouth joints with a paper template.

http://metalgeek.com/static/cope_custom.pcgi

I built my first 50 or so frames with this approach.

[zank]

I just ordered a tube set of double butted chromoly tubes for a bike I'm going to build. I have heard that 309L is ok, but some say use 70s6. Any bike builder out there with tricks or ideas that have made thin wall CrMo welding turn out nice? Thanks

If it's just Nova's 4130, I'd use ER70S-2 or S-6.

[Johnson]

Thanks for the info Zank. I'll let everyone know how it goes. I'll try the spindle sander approch on a test tube and if it fails to work I'll switch to the paper tempate. Should be fun....and a LOT of work