Today we went out and got the parts needed to fasten the wheels to the axles. The setup is pretty straightforward: Evelyn drilled holes into the end of each axle. This hole is where the cotter pin will go (the pin prevents the wheel from coming off the axle). A number of large (5/8″) washers are added between the frame and the wheel and between the wheel and the pin. Here is what the final result looks like:

The wheels themselves have integrated bearings, so the axle doesn’t need to rotate.

Here is a closer view of the front axle assembly. It gives you a complete picture of how it works:

You can see the “sandwich” of material. On the top is a 30″ piece of 2×4. Below are two 13″ pieces of 2×4 which have the dados / grooves cut into them. The 5/8″ steel rod which makes up the axle sits in that groove. To keep the axle in place, a 1×4 is screwed into place. This “traps” the axle — it can only get out from the ends, where the wheels are attached.

The front end is broken up into two 13″ pieces because we need to leave space for the big bolt which connects the front wheel assembly to the frame. We used a 5″ long 5/8″ bolt for this.

There are a number of washers to keep things smoothly moving (two at bottom, two at middle, two at top). Then two big 5/8″ #11 nuts are used to tighten everything together. Two nuts are used because I wanted to “jam” them together (making it more difficult to come loose). Once we have the frame done, I’ll probably come back and add some Loctite or similar to the threads.

For the frame we went with a triangular shape. A center 2×4 is the primary support, as the front axle assembly gets fixed to it (using the bolt shown above). The two side 2x4s were notched toward the front. You can see that they are held together with a short piece of 2×4 in the front (see above photo).

At the back the three 2×4 span is fastened directly to the rear axle assembly (which is also a “sandwich” of 2×4, slotted 2×4, and 1×4). that piece of gray 1×12 you see in the photo is our test seat.

Here is a view of the Kart from the side. We have about 4″ of ground clearance at the axles; about 8 at the center frame.

That’s a five foot ruler sitting on the cart. The wheels are about 38″ edge to edge (using 36″ axles, plus the overhand of the tires themselves).

Next up, putting stop blocks on the front axle assembly (to prevent jack-knifing) and probably some eyes and rope for steering. And, with the frame pretty much complete, we’re now able to brainstorm a seat and body for the kart.