Posts Tagged ‘wooden go kart’

When I was in high school I took an automotive bodywork class. The course included repairing dents, painting cars, welding, playing with a plasma cutter, etc.  Great stuff.  It was a good class and I learned a lot, but one of the most vivid things I remember is the teacher telling us that painting anything, cars or otherwise, is 80% prep work. You can have the most expensive paint, the best gun, a great environment to paint with, but if you don’t prepare it’s all worthless. I remember this as well as the fact that the teacher inexplicably drove his truck through the gate of the body shop yard, but that’s a different story.

A quick break before we dive into our prepwork.

With our kart clearly we’re not painting a full size car, but I did feel we needed to do a fair amount of prep work before we even could consider applying any color to our kart. The first thing we needed to do was remove the wheels, exhaust, etc. It was a bit sad in a way, to have put so much effort to getting the exhaust just right, the wheels in place, the steering linkage, etc. only to say “OK guys, now let’s take it all apart.” Amazingly the boys were not only fine with this, but they really dug in and helped… no really… seriously… what you don’t believe me?

Before we began they asked if they could sit in it one more time before we took most of the pieces off. Oh, and of course, they asked if they could have an Otter Pop as well.

With our Otter Pop break out of the way they got out their tools and went to work. First we put the kart up on our saw horses. The height was just perfect for the boys with the work right at eye level. You could almost say it was their car lift of sorts.  Next I told them we first needed to remove the front wheels.

We started with removal of the front wheels.

I had them each remove one wheel, pull it off and set it aside.  With the front wheels off we then moved to the back. With the wheels off I asked them to place the washer and nut back onto the wheel axle so we wouldn’t lose them. One of the boy’s asked me “What did you call that Dad?”, I replied “What, you mean this washer?”.

He then asked me in a very matter-of-fact way “Why do they call it a washer, it’s not cleaning anything?”. You know he did have a good point. Leave it to a six year old to point out the obvious.

The rear wheels were somewhat of a two-man, or rather two-boy, job in that one of them had to hold a nut that ran through the frame while the other loosened it from the outside.

While they were doing this I was reminded of working in various repair shops years ago, and being under a car that was on the lift at roughly the same level. I was working at a local Montgomery Wards Auto Center.

I had just started working at this shop a day or so before and hadn’t had a chance to bring my own tools into the shop, so my boss graciously let me borrow his. He had a brand new Snap On roll-away. This was the big-daddy of tool boxes. Now things of this level tool box are commonplace, but this was roughly 25 years ago. This tool box had everything, including a built in stereo.

I had a small, front-wheel drive, car on a hoist in front of this tool box. I lifted the hoist, raising the car where the wheels were at my eye level. I then proceeded to remove the wheels, starting with the rear. Let me remind you we had a front wheel drive car,  in the air… with no rear wheels. You can probably guess where this is headed.

Once I removed the second rear wheel I immediately realized I had the car a bit too far forward on the hoist… and it began to take a nose dive into my boss’ tool box. Yes, I soiled my pants, but only after I jumped on the rear bumper as it shot into the air to level the car.

Luckily it didn’t slide off the hoist, and my boss was never to the wiser. For at least a week after that experience I never lifted a car higher than 12″ off the ground on the hoist.  Word of advice… don’t do that.

A bit of wood putty here and there never hurt anyone.

With our wheels all removed from the kart we then removed the exhaust. With this stuff out of the way we could sand all our rough spots and fill in the screw holes with a bit of wood putty. I say a “bit” but one could go so far as to say I applied it quite liberally.

Where we used the most putty was where I wanted to make as smooth a transition as possible to our moulding on the tail. This process required adding putty, drying, sanding, and repeating for what seemed like days. The weather was a bit cool so the putty didn’t want to dry as fast as it otherwise would have.

After some time sanding we were all covered in saw dust and powder from the dried wood putty. Without any suggestion the boys ran off and found some safety goggles to help them with the dust in their eyes. I was really surprised to see how much they were into our progress, it was great to see.

Once we sanded off all the rough edges we took some 3M painters tape and covered the steering spindles and the top of the steering column.  Had I had the room and flexibility I would have preferred to use spray paint, but we went ahead with a foam brush and applied a nice couple of light coats of Kilz exterior primer/sealer to the entire kart.

A white ghost of a go kart. Thank you iPhone for the lackluster lighting.

The wood was all ready to have the primer applied. As for the steel part I wasn’t sure if it would stick. To be sure I went ahead and roughed it up with some really fine sand paper. The kart was really looking ugly at this point, but I knew it would work out in the end. Or at least I hoped so.

We let the primer dry for a day or so, then applied a second coat just for good measure. I’m beginning to see the result of our hard work.  At this point I realized that in pretty short order I’d have to decide on a color for this thing.

Since day one I’ve been on the fence as to whether I should go traditional, “Bugatti Blue”, or something a bit different but with the same vintage feel.  Decisions, decisions.

Until the next afternoon I can squeeze in some progress…

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Lower control arm ready for it's anchor bolt.

As I noted earlier, all of the parts from this project are readily available at most hardware stores. At this point I have my frame more or less together. Prior to squaring it I had to temporarily mount the upper and lower control arms. Once that was done I then removed them and drilled the holes for the king pins (or spindles). The spindles are used as a mounting point for the wheels, but also will provide roughly 40 degrees of turning radius. Go karts are definitely much more fun if they do more than just go straight.

The spindles each consist of 1/2″ galvanized pipe T fittings and are anchored in place via 3/8″ to 1/2″ pipe connectors. It’s really quite a simple and clever setup.  First, I set a center point 1/2″ in from the end of both the lower and upper control arms and drilled a 7/8″ hole about 1/4″ deep using a hole saw fitted to a hand held drill. In rummaging through the endless drawers of my Dad’s tools I realized he had a number of these which made me wonder, why? Some of them had wood bits still within them from the various projects he had done over the years. Luckily for me he wasn’t one to hesitate to run out and buy a specific tool for a task that he would use only once.

After I drilled the larger, outside hole, I then drilled a smaller hole the same size as the threads of the pipe nut in the photo. The idea here is that the nut would be carefully threaded into these holes. Once threaded down the nut would sit nice and flush in the control arm. To get that nice and flush fit took quite some time since I had to sand, and file carefully to slightly enlarge the hole otherwise the control arm would crack or split altogether. You will want to thread this bolt through so that a few threads are exposed on the opposite side of the control arm. At one point I wasn’t able to easily thread it far enough so rather than push it and risk cracking the control arm I took the hole saw out and drilled down a bit further, allowing the bolt to sit slightly lower in the hole.

At this point the thought did enter my mind as to whether or not this would be strong enough for the boys to ride on, let alone to even drive. I figured that the existence of these plans at least implied it was tested after being built, so I put that thought in the back of my mind and pressed on. In all likelihood the overall structure will only get stronger as more of it gets assembled… right?

Bottom control arm with both spindle holes set.

Bottom control arm with both spindle holes set.

Next I mounted the lower control arm back onto the frame. You can see the holes in the top of the frame rails where I had previously mounted the arms for squaring up the frame. From here you can also see the narrowing of the frame to accommodate the turning of the front wheels. I’m not sure how critical having the frame narrow like this is, since the result is that the back is a few inches wider. The plans call for this so I’ve gone ahead and followed it verbatim. As I quickly realized later, that narrowing is a bit of a pain for a number of reasons but I’ll get to those soon enough.

Before I follow up with the upper control arm I need to now insert the T fittings that get sandwiched in between them. First the large connector nut is carefully screwed into all four holes; two on the lower and the two upper.  Next I insert the T fitting into each nut on the bottom, carefully not forcing it to turn too far, and keeping it slightly loose so that it can turn easily. I’ve also added a bit of white grease to the threads for good measure. The easier these turn back and forth the easier the overall turning will be for the kart, so it’s important to spend the time here to get this right.

In addition to the goal of  free spin here, I found I also needed to account for the vertical space limitation. That is if I had the threads backed off too far the control arms wouldn’t mount back onto the frame without a big gap, but if I threaded them in too tight they wouldn’t turn freely enough. I could always insert a shim or something to account for that extra space, but I really didn’t want to do that.

After an hour or two of sanding, threading, some “Dad is the go kart done yet?“s, more sanding and more threading I was able to get the nuts through and the T fittings in place comfortably.

T Fittings mounted in lower control arms.

T Fittings mounted in lower control arms.

With the T fittings mounted onto the bottom, and enough play to both spin, but tight enough to fit in the space between the two control arms I then mounted the upper control arm back into place. Once the arm is in place and screwed back onto the frame you realize that there really isn’t anywhere for the T fittings to go. Even if they were to completely unscrew (which is virtually impossible since they’d be attached to tie-rods) the control arms have them sandwiched in place so again, a simple and pretty clever assembly overall. My Dad would be proud. 🙂

Once both control arms are in place you can see where the threads on the top of the upper control arm, and bottom of the lower control arm, come through just a bit.

Upper and Lower Control Arms with T Fittings in Place

Upper and Lower Control Arms with T Fittings in Place

The plans call for a 1/2″ electrical conduit lock nut to help to secure these in place.  Although these would do the trick they’re not very attractive. You could also use a galvanized pipe cap, but I realized that a brass garden hose cap fits perfectly and could be polished up quite nice. You can see the brass cap here in this picture with everything all in place nice and tidy like.

So far we have our frame, we have our upper and lower control arms, and spindles all mounted. I’ve even gone so far as to drill the holes into the spindles allowing for me to mount the wheels.

Oh wait, wheels. That’s right this thing needs to roll!!??