A bout 10 years ago I was paging through a copy of this very magazine and I saw one of the first tube-framed off-road rockbuggies, and I knew right then and there that someday I would need something like that. It made perfect sense: Have the body and the frame be one, and build them to maximize the execution of extreme trail riding. I wasn't looking for a competition motorsports rig-I wanted only a fun vehicle for off-road exploration, yet one capable enough to attempt everything from mud to dunes to gnarly rock trails. Now after years of planning, drawing, and taking notes about how my ultimate Fun Buggy would look, work, and perform, we finally started the buildup. In our last installment ("Fun Buggy Blueprints," Dec. '06), I went over the design and reviewed my drivetrain choices (small-block V-8, automatic overdrive transmission, aftermarket two-speed transfer case, front and rear steering 1-ton axles), and with excitement in the air I joined the guys from Poly Performance to actually measure, cut, notch, and weld the beginnings of this tube car.
This project is built with a mixture of lightweight sheetmetal structures made of chromoly with all the latest dimple dies, TIG-welding, and heat-treatment for strength as well as a simple cage design of twisted 1 3/4- and 1 1/2-inch DOM tubing. The design process we used had a complete computer aided design (CAD) blueprint showing us where most of the tubes go, and from there it was time to get started on the dirty work.
The work on this machine quickly taught me that fabrication is much harder than it looks. Of course, off-road buggies have been built for years, and that tube-buggy rockcrawler from 10 years ago only just started a rejuvenation of 4x4 owners bending tube and cutting and welding their own off-road creations. But with that growth in home fabrication comes a need to consider the intricacies of building your own vehicle from scratch, not to mention the many tools that make these projects easier. With the multiple forces of geometry involved in a vehicle that can really perform off road, it is important to build a safe and solid chassis.
Think it's too much for you? It may well be, but never let that lack of knowledge keep you from working towards your dream machine. Either work hard to hire a quality shop to build it for you, or get your hands on some tools and start learning on it in your own garage. You just may end up the next Jesse James of 4x4 fabrication.
 From the drawings we showed...  From the drawings we showed you in the December issue ("Fun Buggy Blueprints," page 128), you can see the sheetmetal-fabricated lower substructure within which the transmission and transfer case reside. Additionally the link suspension also ties into this subframe. I rounded up a few sheets of thin 0.090 and 0.080 chromoly sheetmetal to build the substructure with from CalTime Metals. The chromoly is inherently stronger than mild steel, and can be heat-treated to make it very resistant to deformation and abuse. However care should be taken when welding chromoly and it is quite a bit more expensive than mild steel. |  With the drawings of what...  With the drawings of what each sheetmetal component needed to look like, we sent them out to be water-jet cut. Water-jet cutting is where super-high-pressure water is applied with a needle point in order to cut out shapes in metal with very precise results. Each side, end, and top piece was cut out along with various holes to lighten them up and minute tabs to help with alignment. Plus by flaring each hole we added more rigidity to every part. |  Light Racing offers this flared-hole...  Light Racing offers this flared-hole die set made from hardened high-carbon steel. Sheetmetal can be made stronger by cold-working it and adding depth. This provides increased structural integrity by supporting the sheetmetal on different planes, similar to how cardboard is made out of many pieces of paper. |
 The Light Racing kit works...  The Light Racing kit works with up to 0.090 chromoly sheet, and 0.125 mild steel plate. Simply cut out or holesaw the appropriate-sized opening in the material and then align the dies within the opening. Next put the dies in a press with between 12- and 40-ton capacity, depending on hole size and material used. |  With just the side panels...  With just the side panels flared you can see the increase in strength. The nonflared panel bends under the full weight of fabricator Drew Burroughs... |  ...but the finished panel...  ...but the finished panel flexes just slightly. We will use two of these panels to build the boxed substructures. |
 Burroughs starts the TIG-welding...  Burroughs starts the TIG-welding of the substructure with a Miller Synchrowave 250 machine and chromoly welding rod. This lower section will house the transmission and transfer case, will support the lowest skidplate of the belly, and also act as the frame mounting points for most of the suspension links. In order to completely weld these components, everything is clamped together and multiple small tack welds are burned in at the seams. |  Check this out! When Burroughs...  Check this out! When Burroughs had the sheetmetal sent out for cutting he had small alignment tabs added to the edges that would become corners. By simply lining these up and tack welding each part at these points, all the components will be assembled properly. |  Once the chromoly substructure...  Once the chromoly substructure was complete I sent it to Certified Steel Treating. Certified makes its living by changing the strengths of metal. I had two steps done to these pieces. First they were stress relieved and then hardened. Whenever welding is done to metal it can leave stress in the metals around the heat-affected zone of the weld. By going through a heating process known as normalizing, stress is relieved to help reduce the chance of cracks forming in the material. |