How do you weld tubing without it warping?

[dave1273]

HI all,

Ok, got a new problem:rolleyes: , I am trying to weld square tubing together but, when I do this, it is warping and not staying level...

it it 2x 6ft 2x2x1/8in. square tubing that is spaced 2in apart and has 2x1x1/8in. tubing as cross supports, 4 in total...

now, first I tried to weld a full bead and it warped the main rails, then i tried to just tack a few welds and it still warped it....:realmad:

I made sure that it was lying flat and the welded pieces were clamped and I waited for it to cool good before checking it....

WARPED,WARPED,WARPED:realmad:

What it the secret?????:confused:

"If you are wondering what I am trying to make , it is a motorcycle frame jig..."

thanks guys!!!!! GOOD DAY!!!!!:waving:

[chopper5]

you can lessen the warp age by welding all the in side corners first
are you tacking on the corners or the middle of the tube?

[TEK]

Tack it all up then before welding break its back or pre-load it in the oppisite direction of the pull by using a shim under the weld. when clamped down it should be bent away from the weld.

[smithboy]

I have used TEK's method when welding channel end-to-end and with a little practice it works like a charm. Tacking is always a good idea when you are welding multiple surfaces or long distances...I had never thought about welding the corners, though...I'll try that one myself...thanks chopper. That's my "new one" for the day.

[wmb97]

hope you're clamping both the long sections and the cross pieces all to some heavy plate/angle/etc and not just to each other...that'll help, make sure you're not "overwelding" it too

[dave1273]

ok, thanks for the help guys....

I guess my next question is, do any of you know about frame jigs?

If so, I am makeing a fully adjustable jig... The only thing that is not level, has warpage is the 2 main frame rails.

Is it ok to shim my uprights(neck post,rear post,ect.) and the rail plate to make them level and square? just wondering because I read an article on chopperweb that says no jig is gunna be perfectly square... just make sure that the neck and main components are square and that the tubing is cut and mating perfect. Do you believe this to be true?:confused:

thanks guys for the help.... also, are there any specific bike fabricators on here that i can look for for future questions? thanks again...

GOOD DAY!!!!:waving:

[ZTFab]

In my experience(or lack there of) I have shimmed many frames that I've built to make them square.

Obviously the less you have to shim, the better (due to the time it takes) but I would rather have a perfect chassis/frame by spending a little more time on it than not.

I'm a chassis builder (mainly automotive) but I did design and build a Mini Chopper a few years back (when they were all the rage). I built a fixture table for the frame and built a few frames for people.

The one in the pic is/was my personal one. It has a fully functional billet springer front-end, 18hp V-Twin, 205-50-10 rear tire, disc brake rear, drum brake front and had what I believe was an old BSA or Norton gas tank that I bought off of E-bay. I never finished this bike :realmad: ...I got too busy running my shop.

[dave1273]

thats gotta be one of the best looking mini's I have seen....NICE!!!:)

[zapster]

HI all,

Ok, got a new problem:rolleyes: , I am trying to weld square tubing together but, when I do this, it is warping and not staying level...

it it 2x 6ft 2x2x1/8in. square tubing that is spaced 2in apart and has 2x1x1/8in. tubing as cross supports, 4 in total...

now, first I tried to weld a full bead and it warped the main rails, then i tried to just tack a few welds and it still warped it....:realmad:

I made sure that it was lying flat and the welded pieces were clamped and I waited for it to cool good before checking it....

WARPED,WARPED,WARPED:realmad:

What it the secret?????:confused:

"If you are wondering what I am trying to make , it is a motorcycle frame jig..."

thanks guys!!!!! GOOD DAY!!!!!:waving:




10 to 1 odds are that the ends have not been machined square...

if they were this does not happen :nono:

...zap!

[dave1273]

thanks ZAP,

I took the time to square them pretty damn close, are they within a .001 of an inch...no. but , they are pretty square.

why would that matter? what makes that do that?

thanks...GOOD DAY!!!

[ZTFab]

thats gotta be one of the best looking mini's I have seen....NICE!!!:)


Thanks dave. I spent a lot of time desigining the bike to look like a scaled down model of a real chopper. I just wish I had the time to finish it!! :laugh:

- Paul

[ZTFab]

thanks ZAP,

I took the time to square them pretty damn close, are they within a .001 of an inch...no. but , they are pretty square.

why would that matter? what makes that do that?

thanks...GOOD DAY!!!


If I am thinking right, it's a matter of contact surface area. Much like when building a roll cage. The tighter the tubes fit together, the stronger the structure will be and less distortion will occur.

In your case, when you are welding the square tubes together, if there is a gap(even a small one) on one side of the joint, the heat from the weld will cause the tubes to pull together until they meet, causing distortion, pulling them out of square.