Its been a while since Zack and I have been free on the same weekends, but yesterday we put in a solid 4+ hours and finished the steering mechanism. Kira pitched in on the second half of the build, too.
The steering tube is a 3/4″ diameter steel tube that pivots on two aluminum L-brackets. We drilled these brackets way back when with a step drill. That got us to maybe 0.002″ smaller than the OD of the tubing. So we used a dremel with the little sanding drum attachment to open up the bracket hole. If you end up doing things, be sure to move the sander over the surface of the hole as evenly as possible and to never stop in one place. Aluminum is really soft, so it only takes a few passes.
The brackets are just screwed into the frame with wood screws. We used the steering tube to align the two brackets. I’m pretty sure this kind of alignment works better than any amount of measuring we could have done.
Also, things are starting to differ quite a bit from the CAD of this go-kart that I first posted. That’s cuz my SolidWorks license expired…so…we don’t need CAD anymore.
The steering rod block (or whatever its called in the go-kart world…) is connected to the steering tube and its what pulls/pushes the steering rods to turn the wheel assemblies. Here we cut the corners off so that it had clearance to turn all the way.
Next we put the steering block on the steering tube, and just drilled holes through both of them for screws. We drilled two holes from both sides since my drill press ain’t the greatest and can’t really be trusted to drill deep holes without wandering off.
My recommendation is to first drill out both the block and tube with the tap drill size, then take the block off and drill it with the clearance drill size, then put the two back together and use the holes in the block as a tap guide for tapping threads into the tube.
You can also drill all the way through, tap one side of the block, and drill everything else out as clearance.
Woohoo, homemade tools are totally awesome!
Next we worked on connecting the steering tube with the steering wheel. While visiting MITERS this past November, I came across this sweet piece of scrap (I think courtesy of the EV team?) that makes a perfect steering wheel. Although, any bar or round thing would probably work for this.
Here Zack is drilling holes for mounting a small plate to the center of the steering wheel. This plate will then be pinned with the steering tube.
Below you can see this plate clamped to the back of the steering wheel. We also used the step drill and dremel method to make the 3/4″ hole in the center. Here we used a hand drill through the holes in the steering wheel (that were drilled on the drill press) to mark the matching hole locations needed in the mounting plate. Marking the holes like this means they will automatically be aligned.
The steering wheel was a bit rough on the edges, so we cut up an old bike tire for a cover. (Any of you recognize the tire? :p)
Now the fun part of putting it all together: For the steering rods we used 5/16″-24 threaded rods. Its not the greatest method, but it will do. Threaded rods are great in tension, but not in compression. I’m hoping to get away with the compression part, since 5/16″ is pretty beefy. The Real Way to do this is to use both a threaded rod and tube (which is good in compression).
Below you can see the steering wheel mounting plate and the old bike tire zip-tied onto the steering wheel. We used segments of PVC tubing as spacers in the steering column.
But the truth is, until we get motors, this is just a 4 wheeled scooter.