Manufacturing a body lift kit - part two

10th April 2010
As I started to ponder the front and back sections of the body lift frame. I realized as I looked at the chassis that there was in fact more curves than I had originally seen when I appraised these sections. Specifically at the back I had tried to cut a section to fit the side rail by using a bevel gauge to find the angle. On revisiting the chassis it was evident that this was wrong as there was a very small angle 20 degrees at the end of the rear run sections that made the tubing hit it when it sat square along the chassis. Obviously this affected the way it was constructed. I cut the length of each diagonal on the rear of the chassis at 55mm which allowed a small overhang so that it could be trimmed when I had cut the curved top piece to make it fit flush for welding. I then measured 50 mm up each length and marked a center point to cut a triangle out to make the lower angle using trigonometry (tan 20) * 80 mm I worked out the base would need to be 28 mm. I measured and cut this triangle section out and bent the metal to form the correct angle . The curved section that sat around the access panel for the gear lever linkage was going to need to be created entirely on a curve. This would prove to be one of the most difficult pieces to get correct as there was no way to cramp it to the chassis to hold its shape like I had done with the other parts to weld them. The process of getting this curve took some time to get correct as it had to be accurate as the brake line ran directly behind it. I cut the back inspection plate curve at 20 mm intervals there was twenty cuts needed to form the semi circle curve. The rear section bottom angle was made by cutting one 30 mm piece out of the top edge of the box centered on 50 mm from the end of the tubing this gave enough material to be removed to create an angle of 20 degrees. The mitre between the diagonal upright and the curve section was very difficult to get to fit neatly luckily I had a very good friend John to help me and we eventually managed to get a reasonable fit. The front box section I decided was going to be needed to be constructed in two sections. The reason for this was it would be easier to construct two curves each side instead of four in one piece of box section. This allowed for the pieces to be cut and marked so achieving a good curve going over the tunnel that represented the original as much as possible. The lower angle approaching the tunnel was measured at 35 degrees using trigonometry (tan 35 degrees) * 80 mm I calculated that a triangle of 58 mm on the top base edge was required . I then cut slits at 10 mm intervals to allow the rest of the metal to be curved. The front two sections where then cut so the butted up to each other in the center. as you can see at this point the front and back sides had not been trimmed to length. I decided that the two curves front on back were stable enough to be welded off the car chassis. This was good as I wanted to get some experience of welding this material and in filling the gaps I had created with the slits. I knew I would need this as when I returned with the welded section sections I would have a large welding tacking job at hand. The picture right shows all the parts cut to shape. Some of the parts would need to be shortened after the sections front and back where joined together on the chassis. The reason for this was to try to ensure the parts hugged the chassis neatly. With everything cut I was waiting for a replacement welding helmet to turn up so that I could start welding. I was very pleased with the work and the help of my friend both with some of the difficult pieces and the use of his chassis to fabricate this lift kit onto. Whilst waiting for my welding helmet to arrive I noticed that the radius of the curves on the front cross section where different radius's top and bottom of the middle section. This would mean the front section would need the top of it to be remade to the same radius at the bottom. I decided this was something I could do once it was welded.

Manufacturing a body lift kit - part one

28th March 2010.

I had been searching the Internet for a body lift kit that would allow the body to be raised on my Buggy so that the pressure ducting from the turbo would fit under the rear of the body. I had originally considered that I would fiberglass the rear body area , but a good friend had suggested this as another option and it was then I realized it would solve two of my problems, the second being head room. I had really not wanted to change the look of the car to much and after looking at different hood designs I was aware that my head would go through a soft top with the current set up. I had thought that I would have to lower my floor pans to allow the seats to be placed lower than the chassis. This is a large amount of work and the body lift kit idea seemed to cater for both problems. I had found that in America I could buy a BugPack body lift kit. Pictured left. This seemed a little delicate for my off road requirements so I started to source some material to make the lift kit from.

I found a supplier ARC Fabrication Ltd in Hastings that supplied me with 80mm x 40xmm 3.1mm x 1.5m lengths this was ideal as I had been told that I needed four to go around the perimeter of the shortened chassis. I picked up the mild steel box section and started to ponder the best way of fitting it around the complex shape of the floor pan.

There was at least six curves to negotiate and luckily a good friend had a chassis that I could build the lift kit onto and was very helpful through the build process. I had put a thread on VZI asking which was the best way to curve the box section as I new there was several ways of achieving this. The consensus was that bending the material put stresses into the side walls of the material and that cutting and welding was a better option.

I decided I would have to see if there was a mathematical rule for calculating the number of cuts and the distance between the cuts to negotiate a curve. I had been told already that the curve on the leading edge of the chassis near the front needed six cuts that where spaced at 20mm intervals apart to negotiate this curve but had no idea how this had been calculated. This meant I needed to research this as I had to get over the tunnel and this was going to be very difficult without some maths to simplify it.

I started by working on the side rails. Initially these had looked like they only had one curve but in fact they had two on each side. I started by marking the rail were the curve started to come in at the front this gave me a position to start cutting into the rail. I marked the chassis were this mark intersected it so that it could be used as a reference marker to re-align the rail in the same position. I then marked out six cut marks 20mm along each rail, so that the 20mm intervals fell around where the curve was going to come. This gave me my cutting marks. Cut the box section using 1mm metal cutting disks these cut quickly tthrough heavy metal. It is very important to wear safety equipment with these cutting disks as they can easily cut through anything quickly. Three sides of the box section was cut so that it lost its rigidity and was able to be bent around the chassis to form an even curve.I used the 4" C-cramps to initially cramp the longest side onto the chassis. This gave a fixed point so that the the other half of the box section could be levered into position. I used a piece of wooden batten to pull each of the cuts out so making the distances regular and more easy to weld. The process was then repeated for the other side.

It was soon noticeable that the box section cut across the front edge of the floor pan. This didn't look very neat and I decided that if another curve going the opposite was was placed at the end it would bring the end of the box section back in line with the chassis. The angle of this curve was much tighter than the previous one and I decided to make six cuts at 15mm interval to allow for the tightness of the curve. You can see in the picture opposite that the box section now followed the perimeter of the chassis sides. I had only bought with me a few C-cramps and really did not have enough cramps to cramp both sides down hard. The result of this was that I new I would have to return and complete the front and back sections. I had decided to make the front sections out of two pieces and the rear section out of three pieces. The reason for this was to simplify the curves so that the box section would fit flusher with the chassis. I will return to make the front and rear sections in the next article.

Supplier
Arc Fabrication Ltd
Unit 1/2 Bulverhythe Works, Bulverhyth Road, St Leonards on Sea Tel 01424 715220