My flexi-joint on the electric auger was not holding up so well to all the punishment I have been putting it to.
The shock-mount connectors are working just fine at absorbing jolts and off-axis loading, but I'm watching the fourth set of these suckers fail.
So I tried a Ford/GM steering doughnut replacement part, set up the way it was designed and it worked just fine for about three glorious, high-stress minutes before failing.
So my solution was to use stainless bolts to bolt straight through the doughnut and add some rubber washers atop the flanges capped with big washers, and adjust the nyloc-nuts to 'barely snug'. Under off-axis loading, this allows the bolts and rubber washers to flex just a bit, but under full torque load, the stainless steel bolts carry the full load.
After about five hours of high stress digging, the new system is working perfectly.
Problem solved.
-AC_Hacker