Head Tube Warp

[FTMN]

I'm currently building my first frame (fillet brazed). So far, so good until I cooked the head tube a bit too much and now it isn't perfectly round anymore.

My question is this... is any head tube warping acceptable? If so, how much?

I just found this forum recently, and there is a lot of great info here. Thanks!

[Clockwork]

At the ends of the HT measure the shortest diameter and subtract the headset cup diameter and see how thick the remaining wall thickness is.

-Joel

[FTMN]

Thanks Joel!

Is there an acceptable range of remaining wall thickness I should be hoping for?

At some point should I consider head tube reinforcement rings?

[jon_norstog]

FTMN,

Sometimes you can beat an ovalized HT rounder than it is. Depends on how much spigot you have above and below the joints. If you have 50% bite when you ream and face the HT, it is probably usable. loctite makes a product for cases like this.

Alternately, and if the tube is severely out of round, you could do the right thing which is to carefully cut it loose and braze in a new HT.

Good luck!

jn


"Thursday"

[Eric Estlund]

did you use a thick walled piece of head tube stock?

[FTMN]

Thanks for the comments guys. I should have done some measuring before I got worried. I'm using a 37.0 diameter x 1.6mm wall head tube from Nova; its a 206mm section cut from a longer tube. I think it'll be OK (good enough for my first frame) after I get the head tube reamed.

After some more reading, I made the mistake of not heating the entire head tube (including the front). Sounds like that will help minimize the distortion.

I have higher hopes for the top tube/head tube joint now. Thanks!!

[Eric Estlund]

You should be ok. It will take a boat load of heat to warp a 37mm heat tubeinto unusable shape.