Makes perfect sense, thank you. Though I dare say the guys breaking the 27 spline 4340 shafts in JV are in the .01% of wheelers I was referring to as excluded from the 27 spline spline 4340 bunch is enough group.They are until they aren't. We have broken far too many 27 spline inners in JV in the HP 30 we are so fond of out there that is makes no sense to run 27 spline inners. None whatsoever.
Ever wonder why the TJ Rubi front 44 came with the same 27 spline stubs and unit bearings that the Dana 30 did? The reason that it came that way is the engineers understand that when the stub shaft is torqued to spec and is clamping the two halves of the unit bearing together, there is also something else going on. What happens is the flat face at the base of the stub shaft that butts into the back of the unit bearing is creating a lot of friction (just like bolts do) between those two faces. That friction greatly reduces the load on the splines and prevents them from breaking or twisting off.
Also why you almost never see a twisted off stub shaft but instead see broken yokes and u-joints.