Do 45 RPM records need higher anti-skate setting?

Skating force is generated by the friction between the stylus and the vinyl. That's it. I researched it a few years back and learned that the coefficient of friction, which will determine the friction force generated, varied widely like from 0.1 to 0.5 among different records up until the 50s. Since the late 50s the coefficient of friction has been pretty consistent- about 0.20-0.25. That would result is some milligram differences in skating force from record to record. That being said, I have a couple of records and perhaps it is more about their dynamic range, that I have to turn the anti-skating setting up a tad because I will here a little bit of distortion in the right channel. That does the trick. By the way, one of those records in my mind is recorded at 45 rpm incidentally. It is the Apassionata and it is very dynamic. It is an RCA direct to disc. Very high on the goosebumpometer.

Atmasphere, Tonywinsc,
I used to think, as a previous poster, Omsed, posted, that antiskate should be the same irrespective of speed because dynamic friction would apply.
But over the years I have continued to be open to new information I previously wasn't aware of, and willing to modify my ideas if the facts didn't fit them. (Wish that were the case with many scientists).

The OP said all was well with his deck until he played this particular record, and that the problem was solved with an increase in anti skate. If that was the case, then the problem was not with the record, but too little antiskate.

This might fly in the face of conventional engineering opinion, but only if the facts are ignored. The logical answer is that there was more friction, therefore more skating force. And the reason for that would be, as you noted in your example, Tonywinsc, increased modulation, as per studies by George Alexandrovitch, (JAES, 1961). His study showed that on an unmodulated groove, friction remained constant with groove speed, increasing only with downforce. On a modulated groove, friction increased for the same downforce, and also with decreasing radius.

There has been a lot of good, reliable, proven, information on skating forces available for many, many years, which is why virtually every arm was, and is, supplied with antiskate.

John
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We said way back up the thread that groove modulations might in effect alter the coefficient of friction. The only question is and was the magnitude of that effect. I think now it is significant; who could argue with Dr. Alexandrovitch?

But did he really find that "friction remained constant with groove speed"? That speaks to the original question, whether there would be higher skating force at 45 vs 33, and is contrary to our previous conclusion. I can see that the coefficient of friction could go up with decreasing radius, because groove modulations become more tortuous. Have you got an actual copy of this 1961 publication?

I've had conversations with several tone arm manufacturers; they seem to agree that there is no standard for anti-skate forces to be applied to an arm. Put another way they all seem to have different ideas about it.

Thats not surprising to me because we are dealing with varying groove modulations from the first track to the last.

I own two pivot tonearms. Anti-skate is a guess.
To be correct therefore pivoted arms need a different anti skate setting for 33 and 45 RPM records and even different positions along the record.

The best explanation I have personally read that describes this phenomena is from someone that actually tested pivot arms and antiskating. From the Eminent Technology ET2 manual. Page 46

"Antiskating and Frequency Modulation Distortion of Different Tonearm Geometric

Pivoted tonearms are designed so that the head shell holds the cartridge at an “offset angle” with respect to an imaginary line drawn through the tonearm pivot to the stylus tip. The arc traced by the stylus tip extends past the record center and is defined as “overhang”.

This design approach minimizes tracking error. There have been many articles written about the geometry of this design approach. Pivoted arms create several side effects which reduce phono cartridge performance. The first is a skating force which results from two different parts of pivoted arm design.

There is a force component (vector) that is directed toward the center of the record. It results from the stylus drag force vector not falling in line with the pivot point of the arm. This force pulls the tonearm inward and the stylus can be observed as bending outward. This force and the resulting bending can be demonstrated by connecting a rubber band to a pivoted arm around the cartridge body and pulling it straight (away) from the tonearm. Note: the motion of the tonearm is inward and results in bending of the rubber band (cantilever).

If you corrected these forces with an anti-skating mechanism such that the stylus did not bend (you can not really do this because the frictional force and resultant bending varies with groove modulation, stylus shape, tracking force, etc...) there still exists another component of skating.
This second skating force results because of overhang. There are frictional force vectors that result which are not directly ahead of the stylus. The surface of the record is not really moving straight ahead with respect to the stylus tip. As a result, there are force components directed ahead and toward the center of the record. The magnitude of the inward force depends upon the degree of overhang. "

Lewm,
Check out the link to Alexandrovitch and other papers via this link.

He found that with an unmodulated groove, there was no change in friction with radius ie groove speed. With a modulated groove there was an increase in friction, and this increase increased towards the centre, despite, apparently, the reduction in groove speed.

Ct0517,
I don't get the thing in the ET manual regarding the two skating forces. Certainly there is a tiny component of skating force due to the stylus contact point and the cantilever bearing point being in different places, but as far as I am aware that is not a major consideration in terms of the overall picture. But all skating depends on overhang, because it is that which gives rise to the fact that the groove and arm pivot are not in a straight line, thus causing the forces, unlike in the ET which is a linear tracker. If it was set with overhang it would skate too.

John