Do 45 RPM records need higher anti-skate setting?

Atmasphere,
It would seem so.

Lewm,
I think your take on it is right. All I would say is that rather than "headshell" offset angle, it is perhaps better to think of it as "groove" offset angle (which is what gives rise to the tracking angle error, as both the cartridge offset and headshell offsets remain constant while the groove offset angle changes, the error increasing markedly at the innermost radii, giving rise to higher skating forces there).
J
.

Ralph, Yes, but wouldn't you think that a 45 rpm version of any LP would have relatively lower groove tortuosity/modulation than the comparable 33, because the music signal is allowed more "room" at 45 rpm, per unit of time. Thus, I thought the OPs story that increasing AS helped was not consistent with the notion that groove modulation affected the skating force so as to increase it on average. If anything, I would expect a decrease in skating force, on average. That was a point i made way back up the thread.

45s are NOT cut with greater modulation (if they were the sound would be louder through the speakers), the goal of the mastering guys is same volume, so the idea that different anti-skate is required is far fetched. Same anti-skate.

Tracking angle error is negligible in the calculation of anti-skate, the magnitude of changing force being very small, tracking error only being +/- about 2 degrees even for a 9.5" tonearm. No arm's anti skate mechanism is within that range of accuracy, you can ignore that amount of change (that due to tracking error).

I have designed several arms, tested nearly any arm you can name, have dynamometers (force gauges) that can pick up the actual numbers. The theory coincides with actual measured results quite well.

We have some folks who are obviously not science people here (meaning not physicists, not engineers) "correcting" good information with misinformation. Overhang is not part of skating forces, RPM is not, 45's are not cut at a higher groove velocity (groove velocity that creates sound is vertical and horizontal movement), it is just the linear velocity past the stylus that is increased.

Dear Omsed, This is not a university class or a peer-reviewed forum. Anyone is free to contribute in any way he or she prefers. I can say for myself that when I try to explain something, I am in essence stating my own reasoning of the problem for the express purpose of receiving criticism or correction. I want to learn. Here, I take exception with two of your claims:
(1) Overhang DOES have something to do with the skating force. Because of stylus overhang, the stylus can never be tangent to the groove. That is the root cause of the skating force, because the force of friction is always tangent to the groove. Thus a force vector is created with a direction toward the inward path of the tonearm (the real force is not along the arc of the tonearm, but is inward) that in its net expression becomes the skating force. It also would appear that the offset angle plays a role in determining the direction of the force vector created by lack of tangency, the radial expression of which is the skating force. (Perhaps this is not clear, would need a diagram to demonstrate.)
(2) No one is arguing with your statement that vertical and horizontal movement of the stylus creates the electrical signal that is converted into sound. The point made by me and others was that those vertical and horizontal wiggles that the stylus tip has to trace whilst the linear velocity past the stylus remains constant might in effect alter the coefficient of friction between stylus and vinyl, transiently and variably, so as to contribute to variability in skating force. I am not at all sure that this is a real issue, but it is not nonsensical to contemplate it. And having posited these things, it then would seem possible that a 45, if anything, might induce less skating force than a 33, given that the exact same music is recorded on each. This could certainly be incorrect. Have you measured such phenomena?

By the way, are YOU a physicist? What is your background in what science? I am guessing you are an engineer.