Our intrepid race team completed one of the major requirements for building a $500 racecar this weekend, construction of the roll cage. It wasn’t an easy task but having the proper tools, reading the rules eleventy times, and making sure to measure at least once made the job a whole lot smoother.
One of the tools we had this time that we didn’t use in the construction of our Buick was a tubing notcher. Previously we had mangled the tubing with a sawzall and a grinder to make the tubing fit on the Buick, it worked but it really wasn’t the ideal way to accomplish the job. This time around we picked up a tubing notcher attachment for the drill press and it made the process of fitting a section of tubing a piece of cake. It uses a metal hole saw on a guide to do the actual process of notching, the tubing clamp is also adjustable so you can alter the angle of the notch.
The first step to adding a roll cage to our team’s $500 Chevette was to place the main hoop. It was welded to the 2×3 square tubing we installed that tied the front and rear subframes together and replaced all of the rusted out floor boards. Once the hoop was in place, it would provide a base for all of the other bars required.
The next addition to the cage were the rear stays. These are to be located as close to 45 degrees as possible according to the rules our cage was built to comply with. This ended up working out well in the layout of our car as the beam that the rear suspension mounts off of would be the end point of the rear stays when set at a 45 degree angle.
Once the stays were in place we moved on to one of the larger pieces of tubing we would need to make, the main hoop diagonal bar. The main hoop diagonal bar does exactly as its name implies and runs diagonally in the main hoop.
More work was required on the main hoop and a harness bar was added. This is a two piece bar that intersects the diagonal bar and will provide a place to mount our racing harness. It also further strengthens the main hoop. The halo bar was also added, that bar runs forward off of the main hoop towards the windshield. This halo bar will connect the A pillar bars to the main hoop and tie everything together.
The aforementioned A pillar bars were the next step in the process of building a roll cage for our $500 car. These ended up being a bit trickier to fit to the halo bar as the angle they intersected with the halo bar was very shallow and we weren’t able to notch it with our tubing notcher. We ended up notching the A pillar bar as much as we could with the notcher and then finishing the job with a sawzall. Starting the job with the notcher provided a good base to work from and led to a better fit instead of only using a sawzall. One of our main goals was to follow the contour of the A pillar of the body as closely as possible. This is the safer in two ways, in regards to the chassis itself and it also is safer for the driver as it won’t interfere with their line of sight.
A dash bar was then fit between the A pillar bars. This bar is optional in the rules but is highly recommended. The dash had been removed in our car, so it was extremely simple to add this bar that will really strengthen the front portion of the cage and provide an excellent mounting location for the gauge panel.
The next portion of the cage installation was the door bars. Multiple designs are allowed but we decided to go with the “X” design. Our driver position requires a little extra elbow room and the X design created the most. The passenger side received a single door bar as that is all that is required for the rules.
At this point our cage was mostly complete, we did want to add one more bar to our design to ensure our team’s safety. The windshield that was in the car when we purchased it was smashed, so it was replaced with an old lexan windshield from a local circle track team. We wanted to prevent any debris from pushing through the lexan and to also strengthen the halo bar in case of a roll over. We added a bar from the dash bar to the halo bar that has been called the “Earnhardt Bar” after NASCAR mandated it due to a crash involving the #3 car. Once all of the welds are completed it will provide the finishing touch to our $500 racecar roll cage bringing us one step closer to actually racing this heap.