Our old Powerwheels chassis has taken a beating over the past two years now. With that being said, the team decided to create a new chassis and retire the old one. The layout of the new frame is a rather simple design, yet it is structurally sound enough to get the job done. The rear end of the old frame will still be used in our newer since it seemed to be the only part of the old chassis that was not bent or structurally defected.
Andrew, John, and I priced out majority of the important parts, just to make sure that we fit within the budget of 500 dollars for the competition. The following days were then used to gather all the the materials and tools needed. I went to home depot to purchase 4 1 inch square steel stock and I also grabbed my Lincoln Electric welder. Opposed to the previous chassis design, we will be welding most of the frame together. Keep in mind, I am by no means a professional or good welder. I am at best a mediocre welder since welding is an art that takes years of practice.
Once John came to a final conclusion on the layout of the frame. It was then my turn to prep and weld the frame together which took about a 2 week process roughly. The prep work for welding is what takes the longest amount of time. So the first thing I did was take the angle grinder with a flap wheel and I sanded all the ends of the metal stock at the points of where they will be welded at. This prep is very important for any welder for the simple fact that it helps a welder produce clean welds, and it is a safety precaution. This prep takes off enough metal and removes and harmful chemicals that could be covering the stock. After I finished Sanding and grinding the ends of the stock. I then began to weld the stock to the existing rear frame section from the previous chassis.
I gathered all the tools and safety equipment that would be necessary for the process such as a welding helmet, gloves, welding tent, and a welding magnet. I made my own makeshift welding tent from some of the leftover posters we had in the shop here. Then warmed my machine up and began to setup the stock and the existing rear end together using the welding magnet. I used the flat side of the welding magnet to get both pieces of the metal to sit flush with each other when physically connected.
I begin the welding process by doing tack welds in small areas where the two pieces of metal join at. Once I check to make sure that both metal pieces or still flush with each other, I then begin to finish the welding process by closing up every gap between the metals. By this point, I now have completed the total length of the new chassis using just two out of the four pieces of metal stock.
To my dismay, I found out that my welding process did not generate a straight frame. How did this happen? So, consequently when welding you are heating the metal up to extremely hot temperatures. These temperatures are so hot that it can warp and melt the metal and that is exactly what happened to me. So the two longest pieces of metal stock are less than straight on the frame. The good part is that they weren't warped enough to the point of having to redo the welding.
I then began to cut and grind the existing pieces of metal stock to complete the frame by adding cross bars and torsion support bars. By adding these extra bars, this resultantly pulled the frame back to a near straight frame. Straight enough for our purposes that is.
I then proceeded to drill holes for the steering rack and mounted the wheels on.