Tuesday, October 21, 2008

Legs On! The Project Comes Together

At right, Amos has finished his precision drilling and reaming and is beginning to reassemble the parts of the brake pedal assembly onto the brake pedal platform.

Note that in this photo, the pedal platform, bracket, and rod assembly is sitting on the wooden mockup I made several weeks ago to use for trial fitting and testing.

This mockup has proven to be quite useful, both for initial testing of pedal heights and angles, and also as a work platform on which to sit the pedal assemblies while we were working on them.

In the next photo and the ones below, the metal assembly is bolted to new wooden legs in the configuration which we expect to be final, although these legs are temporary ones made of pine.

We also reassembled the throttle and clutch pedal assemblies and pushrods and springs onto their respective platforms.

While Amos was doing all his precision drilling and reaming, I marked and cut the brackets to which the legs would be attached.

We came up with a tee design that would have approximately the same structural function as the steel weldments used in Todd's production design, but our design used rectangular aluminum tubing, bolted together.

I marked the holes in these tee brackets and drilled some of them, but Amos took over for the half inch horizontal holes that would accept the steel rods, including them in his process for drilling the precision holes in the pedal platforms.

Note that - unlike in the first photo, above - the bottom (vertical) part of the tee brackets have been bolted to the horizontal parts by long quarter inch bolts running vertically through both parts.

Amos also drilled the holes for the bolts that hold the tees together. Amazingly, all of these 1/4" holes lined up so well that the bolts just dropped through without any reaming at all. Amos has become brilliantly skilled at doing precision work - with a drill press that has a bent chuck!

One thing you can't see in these photos is that Amos made small spacers out of some scrap aluminum (actually an old shifter kart tie rod!) to fit inside the upper part of the tee (the crossbar) around the 1/4" bolts, so that tightening down on the bolts won't squash the aluminum crossbar. It's made of 1/8" wall tubing, so it's pretty strong, but these spacers allowed us to tighten the bolts quite firmly, which makes the whole assembly more rigid.

One last thing: note the round steel collars next to the platforms and tee brackets. These have set screws in them and will allow us to lock the pedals in place once we've settled on their lateral positions. This idea comes straight from Todd's production pedals, and gives this design its terrific lateral adjustability.

Keep in mind that the legs and feet are pine and the heel board is a piece of pine scrap, long ago painted what looks like might have been white. We plan to eventually replace these wooden parts with poplar, which will look much nicer and also be stronger and stiffer - and less smelly.