Cutting steel for the go kart build can be done in many different ways. I'll show you how to do it with four different methods. First, mark the steel, then drill out any holes for tabs, then cut out the dimensions for the brackets and tabs. For tubing, cut the lengths, and angles. If you focus on cutting all the steel plate and tubing first, you will be more efficient and finish faster!
Mark Steel for Precise Cuts
Marking steel is done with a straight edge and a marking tool. The straight edge can be your square, or protractor. Because steel comes with rust or mill scale, a pen or pencil is hard to see when cutting and may not be visible. Many welders use soap stone because it marks well, and shows up under an auto-darkening welding hood when in cut/grind mode. I chose a different path, and used a razor blade in a sheet-rock knife to do the marking. It gives a precise line and shows up well under my garage lights. For more precise cuts, I choose which side of the line to cut as the cut off wheel is about 1/8″ thick. I suggest marking all of the tabs and brackets from a 3/16″ plate all at once.
3 Steps to Drilling Holes in Steel
After marking where the holes will go in the 3/16″ plate and tubing (brake and throttle pedals need holes drilled in the tubing on the bumper), there is a three step process to drilling holes:
- Hold a center punch over the steel, and hammer the end to make a divot. This prevents the drill bit from ‘walking’ or moving along the steel as you start to drill the hole.
- Use a small diameter drill bit to make a pilot hole. Drill all the way through
- Use the actual size drill bit, to drill out the pilot hole.
Cut Tubing and Plate
There are many ways to cut steel. For all intensive purposes, you only need one tool (an angle grinder) to do the job of all of these other tools. Let’s go over the pros and cons of each:
- Chop Saw: This is great for cutting tubing, and angles up to 45 degrees on tubing, but is not going to work when cutting a large section of plate. The angle grinder can do the job of a chop saw with more precision if you mark your steel correctly.
- Plasma Cutter: This is used to cut thick and thin metal by melting it with plasma, then blowing it away. You hold the torch with your hand and it cuts in any pattern you can move your hand to. A plasma cutter costs a lot of money, and you don’t need to cut anything but straight lines with this build.
- Jig Saw or Reciprocating Saw: I use this mainly for wood working, and it can cut plate relatively well with no dust or funny smelling fumes. A reciprocating saw can be used with metal cutting blades. Cutting with either of these tools is great with steel plate, but will be sloppy on tubing, and will be a huge hassle.
- Angle Grinder: This is the one tool to have as you can use it for the entire build, it is cheap, and does the job of all of the above tools, plus it can sand, grind, polish, and scuff up the metal surfaces. It cuts fast, and wheel attachments are cheap. I used a 4 1/2″ angle grinder for almost all of my cuts.
Bevel Edges, Remove Burrs
Once you have your cuts made, the metal may have little slivers of metal that were nor removed during the cut (called burrs). You can easily remove burrs by running a wire wheel on your angle grinder over them.
If you have a small welder, you can bevel and deburr the edges of the steel for better fitment and weld penetration. Beveling the edge of the tubing is usually done at a 30 to 45 degree angle to the cut where two pieces of tubing will be welded together. To make a bevel, simply put a grinding wheel on your angle grinder and grind off an angled portion of the edge to be welded.
Now that you have all of your steel cut and prepped for welding, let’s start putting this steel together and welding it up!