Anti skate and tonearm damping query

Dertonearm,

I do not understand why you assert that skating force is "null at any zero error point". If you're saying that skating force is null at points of zero tracking angle error (e.g., at the Baerwald or Loefgren points), that is simply untrue.

Skating force exists ANY time the axis of the cantilever is not aimed directly at the pivot point of the tonearm. Therefore, EVERY tonearm with a fixed pivot point and an offset cartridge mounting angle encounters skating force at all points that the stylus is riding on a spinning record.

Don't take my word for it, and let's not argue theory. Just try this simple experiment: find a record that's ungrooved (flat) at the null points of your particular alignment scheme. Set A/S to zero, spin up the record (the faster the better) and drop the stylus at one of the null points.

Unless you're using a linear tracker or a pivoting arm with no offset angle I guarantee it will "skate" inward.

Once you've performed this simple experiment you will revise your theory, because it doesn't meet observed phenomena.

If I've misunderstood your assertion, please explain in other words if you can. I fear your current assertion is potentially misleading for the less experienced.

Hi,
anti-skate force is a ~99% function of the OVERHANG!... have I been missing something?!

Without overhang, no vector force, no skating force.
If you had "underhang" you'd create a vector force once again, but it is not of practical interest other then in the consideration of the vector forces.

Axel

Dougdeacon...you're correct, but anti-skate decreases with velocity so that it becomes less and for all practical purposes, pretty much zero at the end of the LP. That being said, Highly modulated sections of the groove will create more skate than quiet sections all through the record. ...just clarification...I'm sure you know that.

Stringreen

That is not correct, stylus friction follows the classic Amonton law so the friction is independent of velocity. This can be confirmed by a modification of the test Doug Deacon used to demonstrate that Dertonarm's idea was completely false.

Using your blank disc and having satisfied yourself that skating has nothing to do with null points, set the antiskate on the arm so that the arm remains stationary at 33 RPM. Now change the speed to 45 RPM and observe the result.

Axelwahl antiskate is properly a function of offset not overhang.

Mark Kelly

Dear Mark,
use your test, whereby the tip of the stylus only touches the vinyl.
The contact area thereby sees no off-set, and simply assumes the shortest point between contact area and pivot = one of the vectors. Overhang to the spindle is creating another sector, with the spindle to pivot a third.

Thereby off-set is not involved, yes?

Axel