We could have made brass inserts or something, but the main problem was they were old, the plastic was sun damaged, and there were only 3 of them. We found a few launch trailer wheels from the local boat club but these are plastic, with no bearings. Initially it was going to be pedal powered but this quickly changed to electric. Our youngest has “commissioned” (begged? instructed? persuaded?) me to help him build a go-kart. Here’s the kit, and the test setup to work out what all the wiring does (its not all labelled!) and to check it all works (it does). In practice its more likely to be about half that, but that will be plenty for a prototype.
Bolt together go kart frame full#
The motor will draw 10.4A at full power, so these should give us about 50 minutes running. We didn’t want large batteries taking space on the kart and making it too heavy.
Inside I suspect they’re pretty much the same. These turned out to be cheaper than motorcycle batteries of similar physical size and capacity, because we don’t need cold cranking current for a starter motor, so we don’t need large terminals. We also bought two 9Ah 12V UPS batteries. Without power this will just be a gravity racer, so after staring in bewilderment at the huge variety of cheap stuff available from China, we bought a “24V DC 250W Electric Scooter Motor Conversion Kit MY1016 250W Brushed Motor Set For Electric Bike Emoto Skatebord Bicycle Kit” from Aliexpress for £30. We don’t have a lathe, so to get the front wheel spindles made, we emailed a drawing to The Lathe Man, and a few weeks later the parts arrived. To go with this we walked down the road to our local bike shop and rummaged in their junk box for a caliper, and bought a length of cable. Very conveniently the inside diameter of the 25mm tube is 22mm, so some short lengths of the bigger tube will serve as mountings for the smaller tube.Īt the tip we found a bicycle wheel with a 160mm brake disc. The two tubes are 25mm x 1.5mm for the back axle, and 7/8″ (22mm) for the steering column. Below that are some flat strips for general construction, and some more 40×20 for the frame. Two sections of this will hold the front wheels. They are mostly off cuts that looked useful at the time. Having decided roughly how it was all going to go together, we headed off to the tip in search of bicycles, for parts, and to our (very) local Metal Supermarket. The green C section will be some very beefy box section, with one side cut off. Bottom right is how it all mounts to the chassis. Bottom left is the spindle (black), bearings (green) and spacer (blue).
Middle top is a section through the front wheel (red), bearings (green), spacer (blue) and spindle(black). Top left is an idea for the back wheel hub. 6 holes are much easier to mark out: for a circle of radius R, they are just R apart in a straight line. The sprocket carrier was much the same, but needing 6 holes for the brake disc.
It doesn’t really matter where this went, in relation to the main holes, but we tried to get it symmetric by eyeballing the two holes where they line up with the vice. Lastly the grub screw hole was drilled and tapped. When we were happy with everything, we drilled and tapped the bolt holes. Once the circle was spot on, we used the calipers to mark little arcs crossing the main circle.
Bolt together go kart frame trial#
This was done by trial and error using dividers from the outside edge. We put the hub on the axle, and put a bearing in the vice so we could easily spin the part round as we worked on it. To mark the four holes on the hub we needed to work out the straight line distance between each hole, so we could walk the calliper round the circle marking off each hole as we went.
For the wheels, we measured the bolts as being on a 70mm PCD.