First build alignment problem

[jimjamosullivan]

I have been aiming to start frame building for some time now and having studied everything I can for the last couple of years I have finally begun. My first build is a balance bike for my daughter, I have a really simple design.

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Having filed the two mitres on the main top/down tube I was happy with the way the lined up and when i had finished brazing the front end I was again happy with my results. My problem is that having brazed the seattube in pleace it is out of line with the headtube by a couple of degress, is there an easy solve or do i need to rebraze?

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Many thanks
jim

[druptight]

So your headtube and seat tube aren't in plane with one another? Are you sure your miters were in phase with eachother? If it was off by a small enough amount I'd think you could fix it when you faced the headtube, but a few degress sounds kinda far.

[jimjamosullivan]

Would it be possible to cold set by twisting the head and seat tube. There is a good couple of degrees twist.

[P K]

http://www.velocipedesalon.com/forum...1-a-36104.html

be careful

[veryredbike]

Newbie linked to above agrees. Also, keep in mind that kids do fine on those horrific wooden scoots, so even being off shouldn't matter much with their feet on the ground a lot.

Source: I teach 100 kids to ride bikes every year.

[Eric Estlund]

That is two fillet brazed joints- call those a warm up and give it another go. Odds are good that you will spend less time doing it over then you would trying to repair it (before likely just needing to redo it anyway).

Learning that it's ok to start over is a hugely valuable lesson in building.

[Andrew R Stewart]

Learning how to braze two joints and have the attached tubes parallel planed is part of the curve. Tacking and correcting then brazing from the center is part of the method that i use.

But the immediate question is what to do with the construct you have now. Trying to twist things back parallel will prove to be hard and likely destructive i think, given the design. So one possible solution is to cut the joining tube and sleeve it back together. It's far easier to insure a sleeved joint is rotationally aligned then a mitered one. Andy.

[Curt Goodrich]

I agree with all that's been said. In addition to starting over, I'd try bending this. It might be informative and if nothing else entertaining. Good luck and better luck next time.

[JLP]

I've got nothing to add about how to fix that, but that is a great little project, right there. The kid will love that, and you'll love watching them scoot.

[duanedr]

My problem is that having brazed the seattube in pleace it is out of line with the headtube by a couple of degress, is there an easy solve or do i need to rebraze?
Many thanks
jim

This is the hurdle i'm trying get the courage up to attempt my first frame. I think my brazing and joints are acceptable at this point but without an alignment table or jig or anything really to measure alignment, i'm really struggling with how I keep it all in the same plane...

The real nugget of advice in this thread is that it's ok to start over...

[veryredbike]

Can't wait to see how this turns out, will be making one for a friend soon.

[jimjamosullivan]

I redid the seattube joint. Looks to be spot on parallel. More to come as this build needs to be finished by monday(birthday).

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[MrkiMedo]

I redid the seattube joint. Looks to be spot on parallel. More to come as this build needs to be finished by monday(birthday).

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looks nice, but whooha, monday, there seems quite some work before one can scoot on it :)

[G-reg]

Curt already said it, but I was going to say give'er hell and try and bend it. But only to engrain how bad the practice of cold setting a frame is in the effort to make up for shortfalls elsewhere.

[EricKeller]

if it's just 4130, bending it is no problem. OTOH, the kid wouldn't have noticed. I'mna go ahead and speculate the average scoot bike is pretty far out of alignment

[jon_norstog]

JM,

That looks eminently tweak-able. But before you do anything, clean up the fillet at the ST junction and use a couple cheap levels to verify that the assembly is indeed misaligned. If it really is out of whack, mark the side that has to come up, use a couple lengths of pipe inside the HT and ST. And twist.

Good luck.

jn


"Thursday"

[zetroc]

This looks awesome - keep us posted!