11-08-12: DoverThanks very much, Dover. That all makes sense to me, and is consistent with the observations I described. Which would say that as anti-skating is fine tuned by ear, a visual check should also be performed to confirm that no perceptible left or right cantilever deflection occurs, as viewed from the front of the cartridge, as the stylus enters the groove of a rotating record. Perceptible deflection occurring most readily, as a result of non-optimal adjustment of anti-skating force, in the case of high cartridge compliance, low tonearm effective mass, and also, if my understanding is correct, low cartridge weight. All of which is what I happen to have, relatively speaking.
Although the stylus is being pulled inline with the cantilever, there is a resultant force on the arm itself pulling the arm toward the centre due to the cartridge offset and overhang. Now the arm also has an inertia resisting this inward force proportional to its effective mass. Therefore there is more than likely a conflict of forces on the cantilever - inward force applied from the offset & overhang versus inertia of the arm. To my mind the amount of antiskate required is that required to keep the cantilever in line with the groove. I very much doubt that this would be 0, but it would also be influenced by the horizontal compliance of the cantilever pivot.
FWIW, with my Soundsmith re-tipped Grace F9E Ruby and my undamped Magnepan Unitrac unipivot arm I've settled on an anti-skating force equal to about 56% of the arm manufacturer's recommendation. I suspect that their recommendation is based on setting anti-skating force equal to tracking force, which is a ridiculous notion IME.
Doug, thanks also. The concluding sentences of your two posts above seem to sum up the bottom line -- as is usual in audio, things are system dependent.
Best regards,
-- Al