I have just wasted pretty much the whole day trying to cut the parts for this assembly. Wasted lots of metal so far. Anyone have a decent way to cut the compound angles for LA and LB?

Thanks

mark the angle on each face and cut idividual faces, one at a time... that'll get you close enough. then file it down to the correct angle...

I really struggled with the L assembly too but actually compound angles aren't that big of a deal once you've done a few.

The 3 methods I've used them are below. In all cases mark up the rail first on all 4 sides.

For the compound angles on the L section someone has made up paper templates you can print out and wrap round the metal - they're a PDF file on this forum somewhere but I can't find any for any of the other compound angles on the book chassis, especially not the transmission tunnel, which I just did by sight.

1. Set the chop saw for the first angle and use a trolley jack, or some other wedge, to lever up the rail so the second angle is vertical (you can check this with a set square.) You can then do the cut in one "chop" with very little finishing.


Compound angle solution

2. Put the rail in a vice, aligned so your second angle is vertical and cut it with a hack saw manually. This works for rails where method 1 doesn't work because the angle is so sharp.

3. Get close with the chop saw used normally with the rail flat as normal then finish off each of the 4 sides with an angle grinder then file it off nicely. I "fixed" an incorrectly done method 2 rail doing this and used this method from then on - especially for the transmission tunnel bits which I did by sight.

Cheers,
Simon.

Or the simple manual approach...

Spend some time marking out the angles, until they look like they're right. use a hacksaw to cut well proud of the line, then use a fairly coarse file to get down to the line.

It really doesn't take much time...

[Edited on 21/4/07 by David Jenkins]

there was a prog on here somewhere that you printed and cut out ,gave you the right angles

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Originally posted by theconrodkid
there was a prog on here somewhere that you printed and cut out ,gave you the right angles

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Ok, found the template. Will give it a go tomorrow.

Here's a link below for the templates for LA & LB.

These came from a member of this forum but I can't find the original thread to give credit

http://homepages.nildram.co.uk/~walker12/L_cuts.pdf

You can just draw them directly on your rails by setting your combination square to the angles in the mcsorely plans, that's what I did for the compound angles that come later . . .

Hope that helps,

Oh you found them! Nevermind!

Advice re: mcsorely plans stands though for future compound angle cuts.

Well, this is driving me absolutely mad now. However close I seem to be getting I then go over the top and end up with the parts about .5mm too short.... more wasted steel! Another attempt tomorrow

0.5mm! 0.020"? That's plenty close!

Measure each side angle two (even three) times cut once...repeat as needed.
I have cut one side only, and was too tired to make the second so left it alone, I plan to resume cutting tomorrow on a clear and well rested brain (or what is left of it...

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Originally posted by Simon W
about .5mm too short....

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Originally posted by gazza285

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Originally posted by Simon W
about .5mm too short....

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Fill the gap with weld. 0.5mm is nothing.

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I'll try again then.

1mm is nothing, fill it with weld.

Don't fully weld the L uprights 'til you have the front suspension pickups jigged properly - you may have to move them if your brackets are slightly out. or should I say, you will have to move them even if your brackets are perfect.... ;^)
Bob

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Originally posted by Bob C
Don't fully weld the L uprights 'til you have the front suspension pickups jigged properly - you may have to move them if your brackets are slightly out. or should I say, you will have to move them even if your brackets are perfect.... ;^)
Bob

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I'm not talking about moving them more than a few mm - to avoid a lot of cutting or introducing shims or having to bridge a 4mm gap with weld later.
I can't believe the scrutineers will be interested in the position of chassis members to millimeter accuracy (as if any are that accurate after welding!)
Also what do they make of other book errors, like the good old caster angle debacle - do you have to race with no self centring?
It's your decision how you choose to make your actual suspension geometry correct to 'book' - I did it by moving the L uprights a few mm :^)
Bob

Ok, I "think" i have managed to do the L assembly well enough to be happy. Now I just gotta tack it up without blasting holes in the metal!