Create the Welded Base
With the bulk of the work on the stone tabletop complete, the last major phase of the project is to create the metal base and, finally, join the top to the base. For this piece, the base is created from several pieces of metal salvaged from a junkyard: a piece of cylindrical schedule-40 pipe, a plow disc base and leaf springs from an old truck. Unless you are experienced with welding techniques and safety, take your design and metal to a welding shop or create a different type of base.
You can choose any height that you desire. Cut the pipe to size using a cutoff saw with an abrasive blade (Image 1). Smooth and grind away rust from the cut edges of the pipe. Do the same thing with the plow disc base by tracing the area where the pipe sits and then grinding away the rust in a ring. When welding the pipe to the plow disc base, clean metal should sit on clean metal.
Make sure the pipe is sitting level on top of the base. This is where a magnetic level comes in handy. If you need to make adjustments, use whatever you have, like knives or chisels, to hold it in place until the pieces are welded together. Tack the pipe to the base to hold it in place and then go around welding the entire base in sections (Image 2). Once the two pieces are welded together, clean off the old rust on the new base (Image 3) with an angle grinder and a grinding stone.
The base is nearly complete, but it needs something to provide support along the length of the heavy table top. Place two steel strips nearly parallel into the pipe portion of the base to get this strength. Using a cutoff saw, cut the leaf springs of an old truck to length, cut out two notches on either side of the pipe using a plasma cutter (Image 4) and set the springs into each notch. Level the springs, tack weld them, and then weld the entire thing into place.