In Part 1, I showed pictures of the basic frame of the car, as well as the mounting of the rear wheels. In Part 2, I will explain and show the mounting of the front wheels.
I should start off by saying that this is not a go-cart, is not meant for high speed or heavy drivers, and is supposed to be basic enough to not require welding. And I’m learning enough with this go-around that I would likely not do a lot of this the same way a second time.
That said, the front wheel mounting mechanism outlined in the plans is really pretty neat and creative. A kingpin assembly is built up from a galvanized pipe T, with male reducers fitting into each end of the “top” of the T, and a three-inch length of pipe screwed into the “vertical” part of the T to allow for the tie-rod. The wheels are mounted by drilling through the T pieces perpendicular to the three-inch tie-rod post (study the pictures and it should make sense):
The T’s are then mounted “sideways,” with the reducers attached through the two 3/4″ thick wood cross-members to galvanized pipe caps. The wheels spin freely on their axles using the stock bearings (and the stock axles, which happened to be just long enough), and rotate left and right on the reducer threads for a very simple but effective steering mount.
I mentioned previously that some of the supplies available today in the big-box hardware stores are not of the same quality as the supplies available 20+ years ago when these plans were written. One example of this is the tie-rod that is supposed to be used to connect the two front wheels together (not shown in any pictures yet). The plans call for a threaded rod that mounts a steering rod receiver and is bent on both ends to fit into the steering arms on the kingpins. Unfortunately threaded rods today are incredibly cheap metal, and will invariably break when bent. But in the end I discovered that this is a very limited tie-rod design anyway, and allows for absolutely no adjustments after mounting. I surely don’t expect to be able to fully align the front wheels, but there is an advantage to being able to at least rough-tune the alignment.
After stopping at Coventry Cycle Works in Portland last weekend, I came away with some really great ideas for a steering mechanism (I was thoroughly impressed with this place, and am grateful for the assistance they provided!). I learned about a connection called a heim joint that is essentially a ball-and-socket assembly that allows more freedom of motion than a straight bolt and tie-rod might. If I build another of these cars, one of the changes will be in the steering assembly, and I would really like to mount the wheels differently and make use of a pair of heim joints. This would likely coincide with a much lighter kingpin assembly, too, since the galvanized pipe, although creative and cheap, is bulky, heavy, and a “brute force” solution instead of a “finesse” solution.
The cross members are spaced to allow them to slide over the front of the frame, and the top cross member is screwed to the frame sides. The notches in the frame just in front of the front wheel assembly are for the tie-rod, and will be covered with a strip of aluminum to provide a more finished look in the completed vehicle.
At this point, the frame is complete, the rear free-wheel is mounted, the drive axle is bent and mounted, and the front wheels are mounted. I still need to finish the mounting of the rear drive wheel, but will wait to address that in Part 4 since I’m not really sure how to do it yet.
The next post, Part 3, will cover the rough building of the fenders and body, and will get the series of posts caught up to where I actually am right now with the project.
Tags: Pedal car