[rickst29]

The lift arms are about 3/4" thick, and I need about 1/4" of bolt shank sticking out the opposite side of the lift bar (next the the side of the shell) to use ALL the Threads of the terminating nut. Even if I squeeze the lift arm sides together a bit a tiny bit, there is "room" for only 1 or 2 extremely thin washers.

This "straight up bolt" style of 10mm ball mount post is not available with a shank longer than 1" (with 5/16-18 threading on the shank), or 25mm (M8-1.25 threading), which is nearly identical length.

The total length which I need, WITH my pair of really wide and thick washers (1/8 thick each), is about 1-1/2" inches. Wasting a bit more time and money, I bought some M8 - 1.25 12mm-wide round couplers off Amazon. At 20mm, the coupler length fits the lift bar thickness almost exactly.

I also bough some short M8 bolts, and cut down the shank on each of them (two bolts) so that the portion into the coupler, with the washer tight, is a bit less than 7 threads long. I put those in (with locktite).

From the outside, the lift bar ball mount post has about about 8 threads going into the coupler using the big washer alone. (I may add a lock washer between the body of the ball mount an d the big washer, in addition to some medium "locktite" in the coupler threads) This can be tightened to the limits of the 8MM SS bolts and coupler, although I will not push them anywhere near that far.

After attaching to the lift arms, I will add 5 or 6 thinner SS bolts and nuts (1/4" x 1-1/2" long, 20 TPI), arranged in a circle, close to the rim of each big washer. The bolts go wil go all the way through, using tight pilot holes through the lift bar "inside" and "outside" sheet metal plates. There is no "interior reinforcement" to prevent these bolts and nuts from collapsing lift bar from outside in, so I will be leaving the torque low on these "helpers".