Join Date: Nov 2002
Location: Newport News, VA
Basically, it is just added support for the relatively weak (in comparison to say... a Dana 60) axle tubes.
As for JP mag... it is written by guys and gals just like you and me. I learned a long time ago to form my own opinions about things. Almost everything I've learned, I learned from the "school of hard knocks" and mistakes. Rarely do I make the same mistake twice. Honestly, I have stitched up the tubes on probably 7-8 AMC20s without problems. Yeah.. if you tried to run a long continuous bead of weld you can warp it.. you can warp anything if you try to. Key is to weld small areas and move around. If I do a 1" stitch on one side, I flip it over and do the next one on the opposite side. Then, I go to the other axle tube and do the same while the first one cools a bit. It's not difficult to predict how the metal is going to react with the heat distortion and the expansion/contraction associated with the welding heat. With a little experience and some common sense, you can keep distortion to a minimum.
One thing I am striving for on this axle is to keep the truss from "pulling" up on the ends of the axle tubes. If you were to jump a Jeep (trying to bend the axle), it will bend "up" at the axle ends(sort of like a smiley face). Ideally, a truss across the bottom of the axle would be the best way to prevent bending the axle housing as the truss would be loaded in tension upon the tires' impact with the ground. However, who wants a big chunk of steel welded across the bottom of their axle housing to drag around on the ground?.. So, most trusses (we're not talking Baja racers here), are a compromise and welded on the top of the housing. While maybe not as effective, it does still help to increase the axle housing's resistance to bending. However, if care is not taken, the truss itself can actually pull up on the axle tube ends as the welding cools. I made this truss so that it sits on those two ends with about a 1/8" gap under the center (between the housing and the bent tube piece). I'll weld the ends first (a little at a time to prevent warping), then I'll clamp the center down to the cast section and weld it. That will slightly "load" the truss.. pushing down a little on the ends...