Another build thread? Yep, my track-style T

[J. Robinson]

The biggest thing on my punch list before disassembly was the K-member/driveshaft loop. I didn't build this piece when I had the body off because I was afraid that I might mis-measure something and it would end up interfering with the floor or driveshaft tunnel. The alternative, of course, was to get under the car and build the assembly in place. I put this off as long as I could (I hate working on my back and welding overhead), but the time has come...

I began by setting the roadster up on jackstands. I put a stand at each corner and then used shims (pieces of old paint paddles) to level the frame front and rear. The K-member assembly is going to be welded in solidly, so I don't want any twist in the frame while fabricating/installing this assembly.

Fabrication began by forming and welding an oblong loop of 1/4" x 1 1/2" flat steel. The radius of the loop was determined by the contour of the driveshaft tunnel underneath. Next, I measured the distance between the frame rails (23 1/4" inside), subtracted the outside width of the loop (5 1/4"). I divided the remainder (18") in half (9") and cut two pieces of 1" tubing to that length. The purpose is so that the total length of these pieces, when assembled, will fit between the frame rails with the loop surrounding the drive shaft.

I built a temporary fixture from scrap lumber to help me get these pieces welded together straight and even. I had determined from my measurements that the loop needed to rise 3" above the top of the crossmember. I had actually added 1/4" to my inside frame width measurement so this piece would be 1/4" too long when assembled/welded. This allowed me to grind a slight "fishmouth" on each end to help with fitting and welding to the frame. I removed the driveshaft, fit the new crossmember in place, squared it with a tape measure and tack-welded it in place.

Next, I made the bottom crossmember piece from more 1" tubing. This piece was cut to length (+1/4"), bent slightly to fit directly under the driveshaft loop, fishmouthed to fit, and tack-welded in place.

Finally, I made two diagonal braces from 3/4" tubing to fit from the top crossmember tube, next to the loop, to the upper frame rail about 16" forward.

The final picture shows the whole assembly tacked in place under the car. When this is all welded solidly in place, the frame rails will be restrained from twisting and from "diamonding".