I don't have a specific design yet for the lower, front control arms, but I do have some ideas to try out. The cheapest way I know is to do paper, card for foamcore mockups augmented with various materials like string, tape, etc. I decide to use some scrap cardboard in this case. Mostly, I'm trying to figure out approximate sizes, locations and angles for the ideas I have.
I cut some cardboard to the 17 degree inclination the end plate carrying the screw-in ball joints will have, and they will hold the endplate mockup at the correct angle to center the ball joint in its housing at static ride height.
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I created a centerline for the piece, used a compass to draw a suitable hole for the screw-in ring, and left a 3/8" margin around the outermost end of the ring to weld to all-around, and bent the card. Actually, I bent the card before I glued on the 17 degree pieces, but you likely figured that out on your own.
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Mounted up the rough card mockup to the screw-in ring and ball joint assembly.
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From those things I could use come fine elastic line as the "centerline" of the proposed 1" DOM tubes from each bracket/bushing to get approximate angles and look at how big the endplate must be to get sufficient length of weld on the DOM tubes.
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Also, this will allow me to create a more refined mockup where the dimensions are much closer to what will be actually needed in practice. Mounting the lower end of the coilover shock units can be figured. This will greatly influence the overall size of the endplate itself.
Cheers,