Radius arm clearance in axle end.

[Stuart Giles]

It's a very long time since I worked on a Bowdenex setup, but IIRC, they used a special nut that had a machined rebate on the Bowdenex supplied radius arm nuts. the rebate was a close fit in the hole in the front sandwich plate leaving the hexagon on the outside. This was necessary because the two plate sandwich increased the thickness such that a factory nut couldn't pull up on the radius arm thread. ISTR the thread is 5/8 x 16 WF, as per the halfshafts.