Simon W
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| posted on 21/4/07 at 04:53 PM |
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Locost L (front end) assembly
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
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robertst
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| posted on 21/4/07 at 05:00 PM |
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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...
Tom
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ironside
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| posted on 21/4/07 at 05:59 PM |
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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.
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David Jenkins
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| posted on 21/4/07 at 06:27 PM |
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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]
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theconrodkid
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| posted on 21/4/07 at 08:42 PM |
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there was a prog on here somewhere that you printed and cut out ,gave you the right angles
who cares who wins
pass the pork pies
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Simon W
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| posted on 21/4/07 at 09:15 PM |
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quote:
Originally posted by theconrodkid
there was a prog on here somewhere that you printed and cut out ,gave you the right angles
Hammering the search function to try and find it but no luck so far 
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Simon W
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| posted on 21/4/07 at 10:33 PM |
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Ok, found the template. Will give it a go tomorrow.
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ironside
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| posted on 21/4/07 at 11:05 PM |
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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,
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ironside
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| posted on 21/4/07 at 11:07 PM |
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Oh you found them! Nevermind!
Advice re: mcsorely plans stands though for future compound angle cuts.
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Simon W
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| posted on 3/5/07 at 06:51 PM |
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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
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kb58
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| posted on 3/5/07 at 09:35 PM |
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0.5mm! 0.020"? That's plenty close!
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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Angel Acevedo
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| posted on 4/5/07 at 04:33 PM |
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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...
Beware of what you wish.. for it may come true....
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gazza285
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| posted on 4/5/07 at 06:58 PM |
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quote:
Originally posted by Simon W
about .5mm too short....
Fill the gap with weld. 0.5mm is nothing.
DO NOT PUT ON KNOB OR BOLLOCKS!
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Simon W
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| posted on 4/5/07 at 08:15 PM |
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quote:
Originally posted by gazza285
quote:
Originally posted by Simon W
about .5mm too short....
Fill the gap with weld. 0.5mm is nothing.
Was probably a little out, more like 1mm in some places. I had a day away from it today and will try again tomorrow with a clear head 
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gazza285
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| posted on 4/5/07 at 08:58 PM |
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I'll try again then.
1mm is nothing, fill it with weld.
DO NOT PUT ON KNOB OR BOLLOCKS!
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Bob C
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| posted on 5/5/07 at 09:23 AM |
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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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Simon W
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| posted on 5/5/07 at 10:31 AM |
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quote:
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
I dont think moving the L uprights is an option for me as I am building a book spec car that will be eligible for the 750mc locost championship.
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Bob C
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| posted on 5/5/07 at 12:26 PM |
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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
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Simon W
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| posted on 5/5/07 at 03:14 PM |
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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!
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