RE: Skating forces and a zero offset tonearm

Posted by Lew (A) on November 4, 2019 at 07:28:52

In Reply to: Skating forces and a zero offset tonearm posted by Not Yet There on November 4, 2019 at 05:48:27:

I think I wrote this somewhere else not too long ago. For a tonearm with no headshell offset, and only if it UNDERhangs the spindle, there will be only one point of tangency to the groove wall across the surface of an LP, and at that single moment, there will be zero skating force. At any other point on the LP surface, there will be a skating force that is directly proportional to the tracking angle error (the angle by which the cantilever deviates from perfect tangency to the groove). As someone else also pointed out below, the direction of the skating force will change from inward to outward, before vs after the stylus passes through that one point of tangency. Therefore, it is difficult to conceive how one could implement an anti-skate mechanism for such a tonearm, and none of the few underhung/offset-less tonearms on the market even try.

In order for a tonearm with no headshell offset to make any sense, it must be underhung. If it is designed to overhang the spindle, there will never be tangency to the groove and there will always be tracking angle error and skating.

For conventional tonearms that do overhang the spindle and do have headshell offset, as you know, there are two achievable points on the surface of the LP where the cantilever will be tangent to the groove, but even at those two moments, there is still a skating force, due to headshell offset. Such a tonearm (99% of our tonearms) always exhibits a skating force varying in magnitude but always directed inward.

Anyway, that's what I think after thinking about it.

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Follow Ups Full Thread

Topic - Skating forces and a zero offset tonearm - Not Yet There 05:48:27 11/4/19 (8)

Viv Lab Rigid Tonearm - Mel 09:05:18 11/4/19 (1)

RE: Viv Lab Rigid Tonearm - Lew 14:02:23 11/4/19 (0)

RE: Skating forces and a zero offset tonearm - Lew 11/4/1907:28:52 11/4/19 (5)

RE: Skating forces and a zero offset tonearm - Not Yet There 08:59:47 11/4/19 (3)

It's really hard to explain in words... - Lew 14:00:04 11/4/19 (2)

RE: It's really hard to explain in words... - flood2 19:06:00 11/4/19 (0)

Thanks for the great analogy Lew. Rather elegant explanation. Nt - viridian 14:13:35 11/4/19 (0)

Thanks! - FenderLover 08:29:48 11/4/19 (0)

Follow Ups

RE: Skating forces and a zero offset tonearm - Lew 11/4/1907:28:52 11/4/19 (5)

RE: Skating forces and a zero offset tonearm - Not Yet There 08:59:47 11/4/19 (3)

It's really hard to explain in words... - Lew 14:00:04 11/4/19 (2)

RE: It's really hard to explain in words... - flood2 19:06:00 11/4/19 (0)

Thanks for the great analogy Lew. Rather elegant explanation. Nt - viridian 14:13:35 11/4/19 (0)

Thanks! - FenderLover 08:29:48 11/4/19 (0)

RE: Skating forces and a zero offset tonearm

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