welding - gelp required!

[darkcat]

Hi Guys, im working on a custom car project (for myself)

Im currently constructing a chassis from scratch, i know what i want to end up with but im having trouble with alignment etc.

For example:
I have 2 main chassis rails (40x80mm steel) im going to attach them togehter (over the rear subframe) with 2 bars (30x30 steel).

the problem i hve is that i need to make sure that these bars are at exactly 90 degrees to the main chassis rails, both vertically and horizontaly.
Now in a perfect world i'd have some sort of jig, but this ain perfect!

Any ideas on how to align before welding would be most appreciated!

or even better any physical help - will be paid by means of beer :-D

(oh and im TIG welding, by the way, not that it matters)

---

EDIT
im not sure what "gelp" is but lest call it "help"

Edited by darkcat on Tuesday 30th November 10:01

Edited by darkcat on Tuesday 30th November 10:02

[Hip2Bsquare]

I use a large engineers square and then clamp the piece I'm welding to the next piece or a suitable piece of other metal to keep everything aligned. Then recheck alignment with the square again.

[darkcat]

Hip2Bsquare said:

I use a large engineers square and then clamp the piece I'm welding to the next piece or a suitable piece of other metal to keep everything aligned. Then recheck alignment with the square again.

I thought something like that was the way to go.
I had a go at making a 90 deg, er, thing. however, i tacked it and it was fine, by the time id welded it, it was about 5 degrees too wide!

[sunbeam_alpine]

I've got a couple of magnetic thingys which have 45° and 90° angles.

Bought them from one of those travelling tool sellers, and they're very handy.

I take it you're just doing light tacks on all sides before beginning to weld?

P.S. Your typo could have been worse - it vould have been "Gelding - help required"

[Crafty_]

measure diagonally from front left to rear right and front right to rear left, if the measurements differ then its not square..

I assume this is a very lightweight car ? those measurements don't sound all that big to me..

[darkcat]

Crafty_ said:

measure diagonally from front left to rear right and front right to rear left, if the measurements differ then its not square..

I assume this is a very lightweight car ? those measurements don't sound all that big to me..

Yes very lightweight, however those are the 2 main central chassis rails "ladder chassis" if you like. im going to triangulate various structures off that for the engine / body mountings etc.

www.miniv8.co.uk - if you want a quick look

Edited by darkcat on Tuesday 30th November 15:40

[Liquid Knight]

When you tack the metal together tack a support to triangulate the frame. Weld the joint and grind the support off once it's cooled down. Either that or stitch weld it.

[MX7]

You could try the 3/4/5.

http://en.wikipedia.org/wiki/Right_angle#Rule_of_3...