@lewm I mentioned the scratching more as humour, but that is also the motion needed in the wrist if we put a spoke onto the record and help the stylus tip on it as the move from outside to inside.
I already gave the method for a relative test using a linear tracker and pivoted arm earlier. And an estimate of 0.11 Hz offset at 1kHz.
A relative measurement removes the platter speed and W&F from the equation.
But where does one get an LP with a tone on one side? If there a link?
@cleeds if we change the speed of the patter we would alter the tone’s frequency.
The tracking of a pivoting arm would look equivalent to linear motion of the overhang, moving slowly, in a linear tracker arm.
albeit, it is close to zero.