A new way of adjusting anti skate!

No. Not to mention the fact that the skating force pulls the stylus toward the spindle. I agree that groove tortuousity does affect the skating force but not because it affects the magnitude of the friction force. Because.... for the Nth +1 time, friction is not a function of velocity. You can’t bend the rules of the basic science to explain the observation; you have to find another cause that does fit the science.

I am not at all sure I am correct, but my best explanation is that in tracing the tortuous groove, the stylus is pulled along at a "speed" dependent upon the platter speed and the distance of the styus from the spindle. The ins and outs of the groove walls however cause rapid instantaneous changes in stylus velocity, in order for it to negotiate the groove. Each instantaneous change, because it forces a change in velocity at the stylus tip, is an "acceleration". Acceleration is defined as a change in velocity, up or down. So now you have a mass (the moving mass of the cartridge) that is constantly accelerating. This would create or rather require the stylus to endure tiny forces according to Newton’s First Law of Motion (F = ma). It is those tiny Newtonian forces, which have a vector direction in the general direction of the friction force, that add to the net skating force.

I just thought of another possibility: The tortuosity of the groove causes the stylus to mistrack.  Even when we don't hear it, there is mistracking to one degree or another.  During a mistracking event, by definition the stylus loses or nearly loses contact with the vinyl, or the stylus may be driven against the vinyl.  Either type of event would have a minute and transient effect on the instantaneous VTF, the force normal to the groove.  That could indeed increase and decrease friction for fractions of a second. That could cause the ups and downs of the skating force, but not because of "velocity" or "speed" or whatever you want to name it.  Mistracking can occur in the outer grooves, where velocity or speed is maximal or during the inner grooves, where velocity or speed is minimal, and is probably worse at the inner grooves.

I am not at all sure I am correct, but my best explanation is that in tracing the tortuous groove, the stylus is pulled along at a "speed" dependent upon the platter speed and the distance of the styus from the spindle. The ins and outs of the groove walls however cause rapid instantaneous changes in stylus velocity, in order for it to negotiate the groove. Each instantaneous change, because it forces a change in velocity at the stylus tip, is an "acceleration". Acceleration is defined as a change in velocity, up or down. So now you have a mass (the moving mass of the cartridge) that is constantly accelerating. This would create or rather require the stylus to endure tiny forces according to Newton’s First Law of Motion (F = ma). It is those tiny Newtonian forces, which have a vector direction in the general direction of the friction force, that add to the net skating force.

Then could you explain why if you put the stylus on a glass platter or blank vinyl disc, neither of which have a tortuous groove, the skating force still occurs ? 

Sure.  Nowhere did I or anyone else say that groove tortuousity is the sole cause of the skating force.  In fact, I think it's a minor factor causing minor ups and downs of the baseline skating force, which is due to friction of the stylus in a vinyl groove. 

Skating force is due to overhang. No overhang, no skating force. That simple. This is why tangential tracking arms have no need of anti-skate. Tracking tangentially generates no skating force. 

Once there is overhang then there is skating force, but only when playing a record. This is so obvious it should go without saying. But someone keeps insisting otherwise. If the velocity is zero, there is no skating force. If there is velocity with overhang then there is skating force. Clearly then skating force is related to velocity. QED.

"No overhang, no skating force." Wrong. Underhung tonearms produce a skating force except for the one instant that the cantilever is tangent to the groove (the single null point that one can achieve with an underhung tonearm). Haven’t we been through this before? All pivoted tonearms produce a skating force. So if simplicity of the explanation of skating force is your goal (as simplicity is usually your goal), and if you don’t like "friction", then you can say "no pivot, no skating force". 

Also, for the Nth +2 time, speed of rotation per se is not a factor, once the LP is spinning.  If it were, wouldn't skating force get much worse when you play a 45 rpm LP vs  33 rpm LP? And wouldn't the skating force be much worse at the outer grooves of any LP vs the inner grooves? Please read my post a few posts up from here.  I could be wrong about how groove tortuosity adds and subtracts from the net skating force, and I would be happy if you can point out where and why.  Some things actually are complex and resist attempts to simplify.