This Locost build is just
chock full of surprises. The latest involves the suspension bushings. These are purportedly
made for a Triumph Spitfire, a British car from the 1960s, only about one decade removed from the
last of the Whitworth hardware, and still a generation or more away from anything Metric. So when
we got the bushings and sized them up, the 3/8” holes in the middle seemed appropriate enough. All
of the other dimensions, length and diameter, matched the book specs exactly.
3/8" bolt bad, metric 10 mm good
But last night we were playing around with a bushing and a 3/8” bolt, and we noticed that
something wasn't quite right. The bolt seemed a little too loose inside the bushing. That shouldn’t
happen. The bolt needs to be an exact fit so the suspension doesn’t knock it around and loosen
everything up. On a hunch we tried inserting a 10 mm bolt, and surprise! A perfect fit. Which left us thinking, how is that
possible? Some kind of bizarre time warp? Could Triumph actually have used metric-sized bushings fifty
years ago? That seems so unlikely.
Much more likely these bushings were manufactured by some foreign (and by “foreign” we mean
cheap, no offense) company that never heard of British Standard, and made them in a length and
diameter specified by some Triumph aftermarket people in fractions of millimeters. And since they
didn’t have any bushing tubes with a 9.525 mm inside diameter lying around, they must’ve figured 10
mm was close enough. And the Triumph aftermarket people were apparently okay with that, or
possibly didn't know any better.
So now all of our plans for close-tolerance AN suspension hardware are out the window, and we
need to figure out lengths and grade strengths in a whole new language. And we’ll need to remember
to use a 14 mm wrench on the suspension, although I think a 9/16” wrench will work in a pinch. But
maybe before we go through all of that, and before we drill out all of our new suspension brackets
to 10 mm, we’ll try another source for Triumph suspension bushings. Maybe something other than eBay
this time.
Frame tubes labeled and covered in Saran Wrap
Earlier in the day we took inventory on our frame tubing. We’ve been ordering sheet metal and round
tubing for the suspension pieces from time to time, and in most of the orders we included a few lengths of
1” square tubes, since we knew we’d eventually need it. It turns out we went a little overboard and
we now have more than enough 1” square tubing to finish the whole frame. Although not enough for a whole
frame and a steel build table. We're not actually looking forward to making a build table, but we suppose it
has to be done. Although not necessarily in steel.
We might go with the simple MDF-on-sawhorses design. Except we don’t have any sawhorses. We used
to, but over the years we cannibalized the wood for other projects, and now we only have a few
left-over sawhorse brackets. Building an actual solid table from scratch is another way to go, but
big heavy wooden tables take up a lot of room, and they tend to stay where they're built for a long
time. We'd prefer something that we could take apart in minutes and burn for firewood when we're
done.
Laying out the wood frame way back in 2006
We didn’t need a build table for the mock-up frame. We just laid out the wooden tubes on the living room floor,
with duct tape marking the dimensions, and fit everything together. But that was glue, and this is welding, and so the living
room is probably out of play on this one. Still, it’s kind of interesting to note that in order to build a Locost
frame you only need a flat surface twice, once to lay out the dozen bottom tubes, and once to line up
the rear overhang. Everything else is attached to the frame itself, and it doesn’t matter what the
frame is sitting on.
A proper size 3/4" W1 in the mock-up frame
Also interesting is how the Locost book sometimes contradicts itself. The cut list, for example,
has the W tubes made out of 3/4" square tubing. But the text says to cut them out of 1” square tubing. For
most of these discrepancies, we’ll go with the bigger and stronger example, but in this instance we
think it makes more sense to go with the smaller W tubes. They intersect the Y and O tubes at about
a 45-degree angle at either end, so they’ll fit better. Plus, we already cut the W tubes out of
3/4" tubing a couple of months ago. So there's that.
Moving forward, we still have another sixty feet or so of 1" tubing to cut for the basic frame, then
another thirty or so for the transmission tunnel. And maybe a couple of brackets. Just a couple of days. A month at most. Then it’ll be
time to weld.