Is my anti-skating too strong.

My pal had a Grace badged Rega Planar 2, a Grace F9, and a Grace 747 arm.  In the info he had, Grace said to look at the cantilever as the record plays, then to adjust the anti-skate to make the cantilever stay as straight as possible.  This makes perfect sense, and allows for different settings for records, with varying amounts of info to be fine tuned.  I tries it on his Grace and my two arms, and it does work out very well.

Yes, if you had anti-skate engaged that could do what you describe, and the advice to disable for all arm adjustments, and make anti-skate the last is correct.  But experiment, that is the best way to learn.  Learn how to tell when you have over- or under- compensated by arm behavior and by sound. 

MC, Yes, if you can draw a straight line from stylus tip, through the cantilever, that intersects the pivot point, then you have zero skating force.  And to Larry, yes the reason conventional pivoted tonearms that are mounted so the stylus overhangs the pivot and which incorporate an offset headshell NEVER exhibit zero skating force is because, even at either of the two null points (where the cantilever IS tangent to the groove walls), the offset headshell alone creates a skating force.  But no, MC, not every pivoted tonearm exhibits a skating force at all times. Underhung tonearms, of which there are only a few, that have zero headshell offset, will give only one null point on the surface of an LP, but at that one null point, the skating force is momentarily absent, because the tonearm meets the criterion stated in my first sentence. (Pivoted tonearms that incorporate complicated mechanisms for maintaining tangency to the groove at all times are not part of this discussion.)


Mijo, "mu", the coefficient of friction is non-negotiable and is not dependent in any way upon surface area.  Testpilot got it right. It is a constant for any two materials.  There are tables showing coefficient of friction for a wide variety of material pairs.  Someone else mentioned velocity.  No, friction force is not dependent upon velocity, either.  Also, can you say where you got the idea that a stylus tip gouges a grooveless LP? Before you go quoting the "tremendous" pressure of a stylus tip on vinyl, which is arrived at by extrapolating the teeny-tiny surface area of a stylus tip to a square inch and multiplying the VTF accordingly, I doubt the validity of making that extrapolation.  But I am open to contrary evidence that I might be wrong.


In my opinion, the reason that running the stylus on a grooveless LP does not mimic the skating force generated while playing music is that in the process of negotiating the tortuous groove, the stylus tip is constantly subjected to acceleration and deceleration (acceleration = change in stylus velocity, as someone else mentioned; deceleration = negative acceleration).  Each tiny acceleration requires a Force (F = ma), because the stylus tip has mass, pulling the stylus in the same direction as that of friction.  That force is adding to the friction force in a way that does not happen when there are no grooves and no music.

lewm- MC, Yes, if you can draw a straight line from stylus tip, through the cantilever, that intersects the pivot point, then you have zero skating force.

No. Wrong. That is not it. It's overhang. Last chance. Not gonna keep repeating. Explained perfectly clear already. Skating forces come from overhang. Period.

There's videos where Michael Fremer says this exact same thing: skating force is caused by overhang. No overhang, no skating. Nothing to do with the stylus, cantilever, or anything else. Michael Freaking Fremer! But then he tends to address an audience of people who want to listen and learn. 

Well I have tried my best lewm. You have the info. Everyone has the info. What you do with it is up to you. Choose wisely.

Stylus overhang, along with headshell offset angle, was posited (by Baewald and Lofgren back in the early 40s, probably) in order to make it possible for there to be two null points on the playing surface of an LP.  "No overhang, no skating" is flat wrong.  An underhung tonearm with zero headshell offset does generate skating force everywhere on the surface of an LP, except at the single null point.  Why do you insist upon your too simple explanations of nearly everything?

You were correct to fault me for my sentence: "Yes, if you can draw a straight line from stylus tip, through the cantilever, that intersects the pivot point, then you have zero skating force."  Because I neglected to say that at the condition described the cantilever must be tangent to the groove.  THEN you have zero skating force. That's a description of an underhung tonearm with zero headshell offset angle at its single null point on an LP.  MF is not at all my guru when it comes to the physics of playing an LP.  He is often parroting something he was told and is sometimes wrong.  In this case, he was being too simple, like you.