Turntable speed accuracy

"2 mm on the wall" is meaningless, unless you tell us the distance from spindle to wall surface, but in any case it sounds like the effect of stylus drag is very tiny, probably not audible and probably not worth worrying about. Unless I misremember some of the earlier posts, it sounds like the Final Audio, as you have equipped it, is among the best of the belt-drives in terms of resisting stylus drag.

I picked up a Timeline as I was interested in how our Scully Lathe was doing while cutting lacquers.

The Scully uses a 1/8 horsepower Bodine AC synchronous motor, driving a transmission that then drives the platter via a drive shaft.

With the cutterhead cutting on the plate, the laser does not move- over the entire side you can't see the change even when you use a micrometer. Not bad for being built in the 1940s :)

Atmasphere - think of all the "wear and tear" of all the drive train over 70 odd years. I think whilst we have gained in technology, we have probably lost ground in metallurgy, it's the age of junk metals ( PC & non toxic manufacturing processes required ). I still marvel at the lack of main bearing wear in the Final TT which is now over 30 years old.
Love to hear playback via a lathe and good old Mcintosh MI200's that I lusted after years ago.

Lewm - distance from wall is 400mm if you want to do the maths.

Henry - just to say thanks for the inspiration - your video challenge has really upped the game for die hard analogue folk.

Dear Dover, I don't. But I am surprised you were even able to perceive (visually) a 2-mm displacement, although I guess over time you could measure a larger distance and then extrapolate backwards to determine 2mm per revolution.

Lewm - I positioned vertically a silver metal marker, about 25mm wide, on the wall - it was quite easy to check the moving distance from the leading edge.