| Fabrication
is a bit of a chore, but to quote Albert Einstein, "Everything
must be made as simple as possible, but no simpler."
To eliminate the slug, we start with a 1" OD, 1/2"
ID DOM steel tube and bore all but the last 1-7/8"
of it to 3/4" ID. A 3/4" insert is welded into
the chassis end of the tube, which is drilled and tapped
for a right thread 1/2"-20 rod end. The tab is welded
to the outboard end, and then the unbored length of tube
is drilled and tapped for a left thread 5/8"-18 rod
end or track rod end. It probably doesn't make a difference,
but if this way eliminates one more critical weld, I'm all
for it.
Another complexity
is, we use a lot of taps to make these control arms. On
the old version, the arm had to be removed from the chassis
or spindle for any adjustments (and removed from both for
many adjustments), and on this version we use right and
left threads (left thread inboard on the rear tube, left
thread
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outboard on the front tube), so the rear tube length can
be adjusted by turning the tube, and the front tube length
can be adjusted by turning the rear tube until it's free
of its clevis and rod end (or removing the AN6 bolt holding
the clevis to the tab) and turning the front tube. Each
revolution of the front tube moves the rod end and ball
joint together/apart by about 1/10"* which can put
you within about half a degree of your target for camber,
but once you break out the tire pyrometer, you'll be unbolting
the front ball joint from the chassis to get exactly what
you want.
Sheesh, I'm
writing like it's a product already. I'm getting ahead of
myself; the only problem I forsee is this part will be slightly
less locost than the one piece weldment, but hey, if I could
forsee all the possible problems, we wouldn't have to test
at all. When it has passed its static tests, we'll be looking
for a few good test drivers, and then we'll see if it's
ready to add to our parts list.
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