Total Time Spent: ~15 Hours

Journal

Day 1 - June 6

Brainstorming what parts to use: - Engine: either a cheap aliexpress engine, or a predator 212 if budget allows - Motors: either cheap hoverboard motors, or a good one like an my1020

(The more expensive ones would obviously be better, but I'll see how much everything ends up costing in the end) - Metal will likely be random scrap metal I have around, or some from metal recycling. Not too sure where to get metal. - Wheels are pretty good and cheap at harbor freight - Or can possibly use the hoverboard wheels - Not sure where to get parts for steering mechanism

I've created a rough model of the go kart:

I tried to keep it simple while still keeping it professional.
And I kind of kept adding stuff to it as I made it. At first it was just a super basic frame. Then I turned it into a truck. Then when doing the steering wheel I added the elevated beams on both sides. The result turned out pretty cool.

Total Session Time: 3 Hours

Day 2 - June 7

Today was focused on figuring out what parts to use and creating the BOM. I had a rough idea when designing the CAD model, but only for things like the wheels, engine, and motors. For smaller stuff I had to spend quite a while thinking about it.
A few notable parts: - Steering wheel and seat: I tried look for cheap parts for both of these but all of them ended up way too expensive. Nobody is paying $30 for a plastic steering wheel. I opted to 3D print the steering wheel myself and buy a plastic folding chair for the seat. Folding chair is a little rough, cause I'm gonna have to cut the legs off to make it actually fit well. - Sprocket and chain: This was probably the hardest parts to find. Since the engine is this cheap chinese one from aliexpress, it needed a specific type of sprocket that would still fit on our rear axle. For this itself, it probably took around an hour to find. - Motor controller: Finding a good motor controller was harder than expected. I was planning to use one of those box ones with wires sticking out, but after getting feedback from soneone in the Hack Club slack, I found out about BLDC controllers which I ended up using. - Bearings: The tough part about bearings is that I needed a specific inner diameter and outer diameter. It was easy to find one or the other, but not both. The only place I was able to find both was on a specific site for bearings, but it was $5 for each one. I don't think Highway would like that very much so i opted for some cheap bearings on Amazon that arent the exact size, but close enough.

The total price of the kart ended up at just over $300. It's a little more than I was expecting, but it is lower than the $350 at least. That's if I can even get this accepted as a 10 point project...

I also spent some time refining the CAD model. The previous version was the right design but wrong proportion. It was far too big, so I shrunk it down. I also found that in the shrunken down version, it was only about 2 ft wide, so I ended up also having to make it wider and also make it a little longer. A couple more changes too, like the sprocket and chain, steering wheel model, and wheels.

Total Session Time: 6 Hours

Day 3 - June 8

Since the CAD model and BOM are pretty much done, I spent today refining both of those, as well as looking for some parts to buy.

CAD Changes

Originally I was planning to build the seat of the go kart from scratch out of wood, but decided it would only cost a little more to just get a standard foldable chair. Although I already decided this yesterday, I didn't update the CAD model accordingly, so I found a chair 3d model, stuck it on the car model, and chopped its legs off to where its much closer to the ground

BOM Changes

After double checking each of the links on the BOM, it turns out the hole saw kit didn't have a 1-3/8" saw, which we definitely needed. I had to look for a different one that did have it, and this new one has many more sizes but it's like $10 more. Hopefully Hack Club won't mind, because I kind of need them and buying them individually would feel like a waste.
I also added a throttle to the BOM that I will use to control the hoverboard motors.

Finding Parts

I'm guessing we're supposed to wait for the grant before buying any parts, but I'm going to buy some now and hopefully get it reimbursed later. First I wanted to get the two metal rods I need, one for the rear axle, and one for the steering. I picked up the steering axle at a Home Depot, but they didn't have the axle rod I needed. So I ended up having to go to a different much larger home depot to get it. I also looked for hole saws at both but they are way too expensive. I also picked up some washers that I'll need.

Oh yeah, and I finished most of the README file. Should be able to submit this whole project soon 👍

Total Session Time: 6 Hours

Day 4 - June 9

Today was fairly short. I fixed one thing and submitted the project.

I posted my project in highway-pitstop and it seems to be getting positive reactions. One person replied on it and said it would be helpful to know more specifics about the hoverboard motor. After seeing that I tried to find the exact model (which i couldnt find last time a tried) and I did end up finding it this time. It ended up being 400 watts instead of the expected 350 watts. It was an easy fix though, the same motor controller i picked also has a 400w version. The go kart should be nearly perfect now.

Day 8 - June 13

So two days before, alexren replied to my project and pretty much has concerns about if I can finish the project on time. I do believe i can so i replied, but it seems like alex hasn't really seen any replies.

Then yesterday, I decided to just start working on the project anyways regardless of if it gets accepted or not. Maybe even just starting it now can prove that i will finish it on time. I've had all my metal lying on a glass table covered in tools and it was all kinda dirty. I basically spent the whole day cleaning it all up and moving it all into the garage so i can start working there.

And now finally, today, I started doing real work, starting with learning to weld. I tried welding two pieces together but it didn't really work. Then I tried with something else that's a little bigger and it actually worked. But when i tried to weld something for a third time... my whole table shattered.

I guess I should have expected that from welding on a glass table... But tomorrow i'll buy a welding blanket and start welding on a plastic table instead

Total Session TIme: 4 Hours

Day 12 - June 17

For the past few days, I've just continued practice welding. I remember a day or two ago I kept trying to weld 2 pipes together, and it just kept snapping apart. But I bought new electrodes and they work like magic. Those 2 pipes I probably still have to grind down the excess, but I tried on 2 new ones and they are now solidly attached. Now I've basically got 2 long steel pipes, which I'll use for the two sides of the bottom part of the frame. Tomorrow I'll start cutting the ones that go in between, and maybe even weld them.

Day 15 - June 20

I've kind of wasted the past day and a half trying to get the engine to work. I swear it's like I tried everything. New gas, starter fluid, starting it manually, still nothing. I guess all I really did those past 2 days was weld 2 more pipes together. Now I've got 3 of these long pipes. Today I finally caved and bought a new engine.

It's a predator 212. I don't think I would have bought it if there wasn't a sale on it. I got it for $120 which is pretty pricey, but it's not bad considering its like double the power for double the price. I successfully got it to run, and it was so much easier to start then the Aliexpress one. Just fill it up, flick a thingy, and pull.
There are three problems though: 1. It doesn't have a clutch 2. It's pretty big 3. The sprocket I bought will no longer be compatible

For the clutch, I can easily buy one from Amazon to put on it. I've been looking for new sprockets and another concern is if the gear ratio will be enough. I could probably just return the other sprocket I bought for the previous engine. And for the size, I'm not sure. I might just have to raise the bed even higher, and put a hole in it for the gas.