Bill Tindall, E.Tn.
m4 and 3V both quit abruptly.

suggests to me that the shape of the wear is different than V11. This factor would be reflected in the vertical force vs distance curves in the K&K work. Will study these graphs and see what I can see. Well...I didn't see anything revealing. The longer wearing steels approached the transition from down force to up more slowly. But all the steel had approximately linear curves through the transition from down force to up force.

****Something interesting in the K&K paper translated. The slope of this curve is dramatically different with grain variation as a variable.(Figure 11) Blade lifted in just over half the distance with 7 degree up sloping grain than flat grain. This variable is critical in this experiment.