The skating force that acts on a stylus to cause the arm to swing towards the spindle is generated by the friction between stylus and record. It acts along an axis which is tangent to the curve at the point where the stylus meets the record.
If there is no groove, then that simply means the amount and nature of the friction force is different depending on the stylus profile and how much, or how little, it digs into the blank record surface.
In other words, in an arm with conventional geometry, the stylus will have skating forces acting on it if there is VTF and the arm has overhang or underhang, unless something stops it.
The point to remember is that the stylus is stopped from skating by the inner groove face. It is not pushed by the outer.
When playing an LP, with enough VTF the stylus will stay in the groove, but there will still be unequal downforce on each channel. With anti-skate applied, these forces can be equalised. That's the way it is.
There is always a skating force.
If there is no groove, then that simply means the amount and nature of the friction force is different depending on the stylus profile and how much, or how little, it digs into the blank record surface.
In other words, in an arm with conventional geometry, the stylus will have skating forces acting on it if there is VTF and the arm has overhang or underhang, unless something stops it.
The point to remember is that the stylus is stopped from skating by the inner groove face. It is not pushed by the outer.
When playing an LP, with enough VTF the stylus will stay in the groove, but there will still be unequal downforce on each channel. With anti-skate applied, these forces can be equalised. That's the way it is.
There is always a skating force.
Depending on arm length and stylus, it will usually be from 10 to 30 % of VTF. The force varies across the record, so it might change from say 20 to 30 % of VTF from outer to inner groove in the case of a 9" arm.
If, with particular set ups, users prefer not to use anti-skate, then they presumably feel the trade-off is worth it.
This doesn't mean there is no skating force. This would only be the case if there was no overhang, no offset, and no pivot, ie a linear tracking arm. Zero offset arms have skating forces except at one point on their arc.
(Sometimes centrifugal forces are suggested as the cause of skating - the stylus ejected from the groove as if it had been spun and then released. In normal usage, any "centrifugal" force would be that acting away from the centre, pulling the arm. The "centripetal" force is described by the force preventing the arm from moving away from the centre, i.e. acting towards the spindle, as in the case of an object being spun on the end of a string, where there are no additional forces acting on the object. However, the centripetal component of this nature due to the rotational velocity of a tonearm about its pivot is, of course, virtually zero, as it is hardly rotating at all - slower than the hand of a clock.)
