Classic clip...nice one
For reference, the noise one can hear when Ron (RIP) is cutting the lacquer/acetate is actually a vacuum sucking the disc to the turntable, so it doesn't slip when it is cutting.
He also looks at the grooves being cut via a magnifying glass, in order to check the depth and distance between the concentric groove.
The guy who used to cut my acetates used to love looking at the grooves of vintage acetates to see what measurements they were using...what an anorak!