The rear taper was obviously the next job on the chassis. Having recovered from all the hacksawing, welding, and grinding on the front frame horns, it was time to get stuck into the opposite end.
So, out with the hacksaw again, and another mile . . um, twenty five feet . . of hacksawing. The rear taper is normally about 33" long, but because we're putting a hefty kick-up at the back we are adding about six inches - the remainder of the original tube - to this taper. This will give a nicer looking taper than welding in an extra parallel section, which would have been the alternative.
To equalise the stresses induced by welding, the taper is produced in two identical halves, although the bottom half has to be cut off so that the two parts can meet.
After grinding a generous chamfer on all sides of the joint, the next operation is to weld the two parts together, similarly to the front tapers. When the vee is cut from the tube, the internal stresses of the tube cause the two sides to close up. To counter this, the main tube is spaced off the weld jig by 1/8" (3mm), while the very end is clamped down against the jig. After the weld has cooled, the tube is released, and pops up about 1/8". Voila! A straight piece of tube!
The results of all that work: two, near identical, chassis rails. Placed top face to top face, the rear sections line up perfectly. The front tapers curve down by just over 1/8" because the weld is close to the bottom edge, but this shouldn't cause a problem. By the time engine and steering mounts are fitted, this will probably be un-noticeable.
Time for another rest: there's more sawing and welding to come, making the crossmembers and final shaping of the rails. But that will have to wait for now, until we know exactly what the front and rear supension configurations are.