When I have a couple hours to spare I try and hack (and I do mean hack) my way through the soap box car build. As mentioned previously this project was not actually meant to be in the grand scheme of my plans however I was suckered into it by a 5 year old and I’m pleased to do it. The main frame, front steering, and front axle have been fabricated. It was time to get a rear end into this thing. However I have to make a side note here. I always find it fascinating that my wife will apologize for things that don’t meet a certain standard. For example when she cooks something new and it doesn’t turn out just right she feels the need to constantly apologize for it. I happen to think everything turns out fantastic and feel that absolutely no apologizing should be made. By her constantly apologizing for it kind of brings things “down”. I have learned that it is in certain people’s nature to let others know that something has not met their own standard. I can relate to that therefore…I apologize for the quality of this soap box car. It is being built with a “quick and dirty” mentality. Unfortunately I do not have the time to commit to a design that I would be proud of. The car does not meet my standards.
It’s onto the rear axle. The criteria? It needs to support the frame, roll, and brake. No problem. I have looked at typical soap box car brakes; they are usually nothing more then a chunk of wood that gets dragged on the pavement. No good! We need dependable performance with good wear characteristics. I had an extra Shimano rear disc brake set up off one of my mountain bikes so I decided to donate it to the project. It’s a hydraulic set up featuring a 160mm rotor. Since I was only going to run a single disc on the rear axle this meant that I was going to have to incorporate a live axle. This way both rear wheels and the disc brake rotor would all be connected solid to a rotating axle.
So the axle build was started by punching out the wheel bearings that came with the purchased 10 inch wheels. Next a ½” keyed axle, a couple of flange bearings, and three ½” hubs were purchased. 2 of the hubs were machined down in order to fit the 10 inch wheels. The hubs were machined to ensure a slight press fit into the hole where the wheel bearings were punched out from. The wheels then got spun up on the lathe at 900 rpm to ensure there was no excessive lateral run out. Once true, the hubs were then TIG welded into place. The 3rd purchased hub was then machined down to fit the 160 mm Shimano rotor. 6 holes were drilled and tapped and the rotor was bolt on. It too was inspected for lateral run out and was tested to be 100%.
So with the wheels reworked and the rotor set up fabricated I moved onto the axle housing. The housing material used was the same as the front axle, a chunk of ¾” gas pipe. I built, and welded on, a couple of axle flanges in order to support the flange bearings and the brake caliper. The axle support mounts were welded to the frame and the axle was bolted in using 1.5” muffler clamps. I was able to mock up the rear axle in order to check the caliper to rotor clearances. I needed to machine a couple of aluminum spacers in order to space the caliper out to allow for proper clearance.
With the rear axle complete it was time to move onto the pedal box and master cylinder set up. First a floor board was built in order to establish proper spacing. The driver was test fit in the cock pit and dimensions were measured. With the bracing welded in place the next step was to fab the brake pedal. I machined a section of aluminum the same dimension as a handlebar in order to clamp the bicycle master cylinder to it. Some vertical support brackets were cut up and welded in place to allow for mounting of the aluminum master cylinder mount. Next a very simple pedal pivot was made out of 3/8” cold rolled round bar. I had aluminum checker plate left over from the lathe stand project so I plasma cut a good sized brake pedal out and riveted it to the pivot assembly. The floor board was also cut from the checker plate as was a dead pedal for the right side.
So as things presently sit I have myself a rolling chassis with steering, brakes, and the works. Next everything needs to get tightened, adjusted and mounted solid and it will be ready for some trial runs before getting enclosed. I am not planning to make this car serviceable. The body is going to get welded on. My only access for service or repairs will be from the open undercarriage or what I can access though the cockpit.