If you have seen my first instructable, you will know that I have built a go kart. Well, I found that when going round corners it flipped very easy and the seat acted as a sort of roll bar to stop it fliping over completely.
This dameged the seat and I thought I would build a roll bar to strengthen up the whole machine and to stop it from damaging the seat when it rolled over.
The roll bar consists of about 4cm by 4cm box section. These are the following tools you will need to build this:
An angle grinder (or hacksaw)
A MIG welder or an ark welder
A drill of some sort (a piller drill is best, although a cordless drill will do fine)
Wire brush (unless you have a wire brush attachment for an angle grinder)
This roll bar is useless if you haven't already built the go kart.
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Step 1: Making the Curve - Cutting
This step is a really important one - you have to get it right!
To make the curve in the metal, first you have to cut out a small triangle shape in the box section. The pictures show all the measurements needed to cut out the triangle.
There should be 68cm at either end of the box section. When it is all completed, the overall height of the roll bar should be 95 cm, and the width should be 52 cm.
Do not copy the actual pictures as they are not to scale, please copy the measurements written on them. The pictures are only there to give you a rough idea of what it should look like.
Step 2: Making the Curve - Bending
This step is the easy part. Just bend all of the metal so that all the triangles are closed up. Then the roll bar will start to take shape.
Make sure the gaps are completely filled otherwise the angle will be two big and the bar will not fit on the go kart.
Step 3: Making the Curve - Welding
Now we get to the hard part - unless you like welding and you are good at it, then I guess it will be quite easy.
Make sure all of the triangles are closed up and just weld a tiny bit on to hold the metal in place. When all of the gaps are held in place by tiny bits of weld, and you have checked that the height, width and length are all correct, you can weld them fully.
Step 4: Attaching the Roll Bar
This step is quite hard as it involves a lot of thinking. The way I attached the roll bar onto my go kart was by welding a horizontal bar accross the bike half and then welding the roll bar to that.
This worked for me, but because there are so many different bikes this won't work for all of them. You'll just have to figure out how to attach it to your go kart.
Step 5: Painting the Roll Bar
First you need to get a wire brush, or an angle grinder with a wire brush attachment, and remove all the rust from the metal. This took me about 2 hours because all I had was a wire brush and very rusty metal. Cleaning the metal is the most important part of the painting process so take your time a be careful.
When all the rust has been removed from the metal you will want to paint it with Primer. This just stops any rust from reforming after it is all complete. I have got a picture off the internet of the kind of primer that I used. It works well for me and I would recommend it.
Next you can paint it with a spray can. I had a black can but obviously you can paint it whatever colour you like.
Step 6: Adding a Seat Belt
This is really only just to stop you falling out if you crash or flip the go kart.
You will need to drill a hole just under the first bend in the roll bar. Next, drill a hole at the very bottom of the roll bar and bolt the seat belt anchor to this.
Next, attach the bit that usually goes next to your head when your in a car. This should be bolted to the hole that you drilled first.
Now you can fit the seat belt roll assembly to the side of the bike, making sure that it is in the same orientation as it was in the vehicle it came from.