The frame is assembled starting with the lowest parts of the frame I call the frame rails. These are the longest pieces but are fairly simple bends. The most difficult part was the very back because it curves upward but also bends to the side. The BendTech software makes this as easy as possible by showing where the bends occur. You just have to stay alert and make sure the tube is installed in the bender to get the correct shape. The frame rails run from just forward of the instrument panel to the rear of the chassis and are connected in the front by the lower nose.
The front of each frame rail is butt welded to the lower nose which ties all three pieces of the lower frame together into one piece. After this is assembled I started to work on window frames.
The RT will not likely have a full windshield like a traditional auto, but will probably have a small wind deflector at the lowest part of where the windshield would be located. The entire front top of the RT is composed of the Windshield frame. It is a long sloping frame that mimics the nose in shape at the front and provides the windshield opening at the back. I make this piece as a left and right side and then butt welded the two halves together to form the frame. After this was completed, I fabricated two small nose uprights that suspend the front of the windshield frame above the lower nose. This is the first time I needed to cut the ends of the tube into a "fish mouth" shape because the lay perpendicular to the nose piece. I tack welded the uprights perpendicular to the lower nose and then laid the window frame on top of the uprights. I could now fabricate the left and right "A" pillars which will support the back end of the windshield frame.
The "A" pillars were bent and the proper fish mouth cut made in the ends to properly fit the frame rails and windshield frame. I marked where on the frame rails the A pillars would be located and then temporarily held them in place with clamps so they would not move front to back. I then carefully lifted the windshield frame and so that it now lay on the nose uprights and the A pillars. I jigged and squared all pieces until it was perfect and then tack welded it in place.
The hip rails form the sides of the cockpit and attach at the front to the A pillars. At the back they are tied together by the tail hoop. I started by making the hips rails and cutting the fish mouths where they attach to the A pillars. The I fabricated the tail hoop and butt welded all three pieces together to form an assembly. I also cut two straight "B" pillar lower braces that form the lower end of the "B" pillar as well as support the hip rail/tail assembly. I assembled all the pieces and carefully squared it to the frame rails then tack welded it in place.
The "B" pillar is the vertical frame at the back of the cockpit. It is one large hoop and sits on top of the hip rails where they are supported by the lower B pillar support. I also fabricated two A-B pillar supports that tie the top of the windshield frame to the B pillar, extending over the top of the frame. I set the B pillar on the hip rails and clamped it in place so it would not move. Then I set the A-B pillar supports in place and tack welded them at each end. Once I was sure everything looked and measured square I tacked the lower part of the B pillar to the hip rails.
The tail is braced by two long straight tubes that extend from near the back of the tail hoop to the top of the B pillar. They line up with the A-B pillar supports laterally. I cut and welded them in place.
The front suspension is tied to the frame by two uprights on each side of the nose. These uprights extend from the lower nose straight up and tie into the windshield frame. I cut and fitted each fore and aft upright in place, then welded them in place.
That pretty much describes the major pieces of the frame and how they were assembled. Additional braces and cross pieces were added for rigidity as well as for attaching future components such as seats and the rear suspension arm. At this point the frame is fully tack welded and looks very much like a small car frame!.