Friday, 8 March 2013, 3pm
Another long break since the last blog. Putting the back end
together involved a lot of machining and a lot of waiting for epoxy to harden
around threaded inserts.
First off the rank was making the frame to hold the rear
cross-shaft/swing arm pivot from a few bits of M-board –
I riveted the outer bearing brackets in place, clamping them
back-to-back with a bit of tube through the bearings to make sure they would
line up. Fancy bit of clamping –
After fitting the frame tube mounts similar to the front
ones, these members were clamped in place on the floor panel and bolt mounting
holes drilled in the ends of the tubes. The rear cross-shaft has been fitted to
check the alignment of the bearings –
Next up I machined the threaded inserts to connect the
supports to the floor –
The lugs are to ensure positive location of all the
brackets. Gluing the outer mounts in place –
The large alloy plates are to spread the load -
Threaded inserts are fitted to the inner mounts -
Note I have started drilling 2mm holes either side of the
inserts, the epoxy being introduced on one side until it starts to exude from
the breather hole on the opposite side. And here are the brackets that they
mount into riveted to the M-board -
I’ve been using large ¼” rivets, drilled out to 3/16” and
then riveted from the other end with 3/16” rivets, thereby making double-walled
and double-headed rivets. These are the inner mounts fitted in place and bolted
to the floor –
Note I’ve also added a couple of small brackets to the
inside of the outer bearing mounts to stiffen them up.
These are the forward floor brackets, made from one big
chunk of high tensile aluminium -
The thicker band at the top of the circular holes will later
have slots filed in them to house the carbon fibre seat mounts. This is where
they fit –
The right hand tube extends inward beyond the mount to
support the derailleur dropout. And this is what it all looks like bolted
together –
So that’s most of the chassis finished and most of what’s
left to do is fiddly stuff. I’ll probably be finishing off the drive train
next.