https://lh3.googleusercontent.com/-R...November272012

I sloppily removed the clutch contraption, apparently without
functional damage to the grass trimmer.

I need to attach a 1/4 inch aluminum rod to that threaded bolt
sticking out from the crankshaft. Looks like it uses an uncommon
5/16"-20 bolt.

Any common or easy to get small plastic or metal parts threaded
5/16"-20?

A workaround (see the picture)...

I suppose some plastic or aluminum could be stuck over the bolt
and glued onto the base. And then the trimmer could be started and
used like a lathe to cut a hole for the 1/4 inch aluminum rod that
it will drive. That assumes the base is sturdy enough to twist the
rod. If so, maybe the bolt could be cut off to reduce the depth of
the additional material.

Apparently the shiny metal piece stuck on the black plastic is
used for timing the engine. With the opposite side of that metal
piece being there for a counterbalance. That's my guess.

Thanks.