A new way of adjusting anti skate!

But I wonder if in at least some cases, the manufacturer marks the dial as a guide only.

Agreed Lew, it is just a reference scale from the manufacturer

I am very impressed on my analog rig sound, the DL-301 although cheap it is incredibly good, rivals my digital, better soundstage

@lewm I still not get it how the OP goes about doing this floating arm. Is he attaching some kind of string to the headshell and then zeroing the digital scale with no AS and go from there? 
Every tonearm has some degree of AS even when the setting is at 0, so even the smallest angle on the string would affect the value.

I use Analogmagic as my baseline, then move from there.

I believe that with either the Wallytractor (which  has the limitation of not having all the spindle to pivot arches) or the Smarttractor and Analogmagic I can set the cartridges very easily and precisely.

what are your thoughts?

The SME V antiskate dial has a recommended number to match the VTF, which according to some things I’ve seen out there equals about 10% of the VTF in actual force. YMMV… 

Tangential fan for decades, now....

Skating is something best done on a rink; anti-skating should be relegated to the name of an aunt....;)

WT'Bot?! *L* 

Lew it is headshell offset angle. The reference is to the arm's pivot not the record. The equation works fine. The variation is in the kinetic coefficient of friction which changes with groove velocity. The recommended value is 9 to 11%. I just round it of to 10%. 

You can not hold the gauge vertical. All that I tried gave unreliable readings this way. I used a 1 to 1 pivoted arm to change the force from horizontal to vertical. The scale sits on the platter as usual. The floating arm which is drifting outward because of the antiskating force is then located against a pin in the vertical arm of the 90 degree lever. The force is transferred to the scale and you have a measurement. The lever arm should place some downward force against the scale which you cancel out with the tare button. The quality of the bearing is critical. Cheap bearings out of router bits will not work. Ask me how I know! I used a tiny, oil free, ceramic ball bearing. You want a scale that measures down to thousandths. I'll email you a picture when I get a chance. 

Took most of my first cuppa joe this morning to parse this thread.

 I seem to recall adjusting this visually after balancing my tonearm in neutral, and sort of compromising on too little vs. too much movement of the TA as I made AS adjustments at outer-mid-inner points of the platter. 
 

then adjusted VTF and as a final check, looked at the cantilever position to make sure it was centered- it was.  I used a Tracking Wizard disc for TA setup initially.

Now I could have done something like played a 1 kHz tone from my Ortofon setup disc, run the cartridge output through my oscilloscope and compared L-R values in real time.

Nah. Visual and auditory seem to work for me so far.

My dad was a tool and die maker, got into plastic injection molds in the 1960’s. Company he worked for got the contract for the very first Bic pens and butane lighters. He passed on a 1% stock ownership option he regretted to his dying day. A WW2 vet, he merely said he was a Zippo man and let it go at that. I used to stop by the shop to watch him work and he showed me once how he could judge 1/25,000 inch thickness change using a thumbnail. The human machine can be nearly as accurate as machine measurements- he used laser interferometry for projects for NASA with a millionth inch tolerance, “rule of thumb” being too broad an application for such refinement.

upshot here is the last comment I read was the last I think I need before I pour another cup and move onto some paperwork-

“@lewm

9,731 posts

12-28-2021 1:59pm

Use an amount that does not give you distortion in the R channel (too little) or in the L channel (too much) and does not result in a deviated cantilever after several hours of play.  And then, forgeddaboudit.”

Wise words. Thanks.

Mijostyn, There you go again! Velocity is NOT a factor in determining the friction force. Friction force is very simply equal to the net force vertical to the contact surfaces of two objects (VTF in this case) times the coefficient of friction, which is different for any two materials in contact. So pre-supposing an effect of velocity on the skating force is invalid, if the angle in the equation for skating force is equal to the headshell offset angle. If velocity was a factor, you would have to change AS significantly for 45 vs 33 rpm LPs. Not to mention that the outer groove velocity is so much greater than the inner groove velocity that "velocity" would dominate the problem of setting AS. In your last post, you say the angle IS the headshell offset angle, but then you go on to say, "The reference is to the arm’s pivot not the record". I am not sure what that means. Headshell offset angle is the angle by which the headshell is "bent" with respect to the arm tube, as I am sure you know. It’s a constant at all times. But tracking angle error (TAE) is constantly changing during the course of play. This aspect of TAE causes a constant shift in the direction of the friction force vector which alters the magnitude of the skating force. So I posited that the "angle" in your equation could be defined as TAE + headshell offset angle. At the null points, TAE is zero but headhell offset alone still causes some skating force.

In the above, I confusingly wrote, "So pre-supposing an effect of velocity on the skating force is invalid, if the angle in the equation for skating force is equal to the headshell offset angle." That’s wrong on the surface. I meant to emphasize that velocity is not a factor, regardless of angle. And as a separate matter, the equation quoted by Mijo is also invalid if it is dependent only upon headshell offset and not TAE.

@normb ,  listening for distortion and watching the cantilever displace as it hits the record are sort of arbitrary. To get a good cartridge to distort requires very high groove velocities that over estimate the AS force required. The cantilever displacement was useful in the days of high compliance cartridges but not with the ones we use today. They are too stiff. Frank Schroders advice to set it so the arm slowly drifts inwards when placed between grooves in the run out section is probably the best low tech way of setting it. The equation I mention above is very specific except there is no one value for the kinetic coefficient of friction. There is a range. Using the Wally Skater and my device are really very simple and you know exactly what you are doing with a very specific target which is reassuring. Then you just forgetaboutit.  I have also used my modified gauge to verify that the Schroder method does indeed come close and using the blank record method consistently over estimates the AS force. I did not study cantilever displacement because by     the time the cantilever starts deflecting with my cartridge the AS is way off.  

TL;DR after @millercarbon’s and @lewm’s first posts (both of them being excellent, and I agree with them).

Trigonometry aside, and one thing that is lost on most individuals is "what are you adjusting for?"

The obvious answer is distortion, but all too frequently (and very much like tracking force), being able to track the most challenging A-S track on your test record is not necessarily ideal.

Excess tracking force and anti-skate (even if within your cartridge manufacturer’s specs, as far as tracking force is concerned), will likely compromise the dynamic presentation.

That’s a big "no-no" in my book, and the more I do this stuff, the more my final tuning steps address dynamics.

Now, in no way does this mean that I like distortion (quite the contrary), but given the choice of very good distortion performance with outstanding dynamics, vs. outstanding distortion performance and mediocre dynamics, I’ll always choose the former.

You might say that in phrasing the above choice the way I did is a straw-man argument, but the fact is that dynamics fall off a cliff very quickly with either too much tracking force or too heavy a hand with anti-skate.

I make a big deal about this in the free setup report you can pull down from my website.

... Thom @ Galibier Design

The best way I've seen, as well as explained was by the the Soundsmith guy, forget his name. He just places the stylus in the dead wax or run out groove and observes the behavior or movement of the tonearm/stylus. Too quick, bad...nice and slow and smooth, just right...thats how I've been doing it.

Mijo, for the Nth time, stylus velocity is not a factor in determining the magnitude of the skating force.  Thus your statement, "listening for distortion and watching the cantilever displace as it hits the record are sort of arbitrary. To get a good cartridge to distort requires very high groove velocities that over estimate the AS force required.", contains an invalid suggestion that stylus velocity affects the skating force. Also, further up the thread you intimated that the coefficient of friction will vary across the surface of an LP.  No it won't. For any formulation of "vinyl" used to manufacture a typical LP and the diamond stylus, the coefficent of friction is a constant.  Otherwise, it would not be called "the coefficient of friction".

I apologize for the pedantry, but at least we can get the basic science right. Then we can disagree on everything else. Which is cool.

@lewm, you are using the WRONG definition of groove velocity. It is not the linear speed of the record by the stylus. It is the actual speed of the stylus in the groove which is a direct result of the degree of modulation. The higher the modulation the faster is the groove velocity. The higher the groove velocity the stronger will be the force Friction) pulling the stylus away from the pivot. GOT IT!

No. Not to mention the fact that the skating force pulls the stylus toward the spindle. I agree that groove tortuousity does affect the skating force but not because it affects the magnitude of the friction force. Because.... for the Nth +1 time, friction is not a function of velocity. You can’t bend the rules of the basic science to explain the observation; you have to find another cause that does fit the science.

I am not at all sure I am correct, but my best explanation is that in tracing the tortuous groove, the stylus is pulled along at a "speed" dependent upon the platter speed and the distance of the styus from the spindle. The ins and outs of the groove walls however cause rapid instantaneous changes in stylus velocity, in order for it to negotiate the groove. Each instantaneous change, because it forces a change in velocity at the stylus tip, is an "acceleration". Acceleration is defined as a change in velocity, up or down. So now you have a mass (the moving mass of the cartridge) that is constantly accelerating. This would create or rather require the stylus to endure tiny forces according to Newton’s First Law of Motion (F = ma). It is those tiny Newtonian forces, which have a vector direction in the general direction of the friction force, that add to the net skating force.

I just thought of another possibility: The tortuosity of the groove causes the stylus to mistrack.  Even when we don't hear it, there is mistracking to one degree or another.  During a mistracking event, by definition the stylus loses or nearly loses contact with the vinyl, or the stylus may be driven against the vinyl.  Either type of event would have a minute and transient effect on the instantaneous VTF, the force normal to the groove.  That could indeed increase and decrease friction for fractions of a second. That could cause the ups and downs of the skating force, but not because of "velocity" or "speed" or whatever you want to name it.  Mistracking can occur in the outer grooves, where velocity or speed is maximal or during the inner grooves, where velocity or speed is minimal, and is probably worse at the inner grooves.

I am not at all sure I am correct, but my best explanation is that in tracing the tortuous groove, the stylus is pulled along at a "speed" dependent upon the platter speed and the distance of the styus from the spindle. The ins and outs of the groove walls however cause rapid instantaneous changes in stylus velocity, in order for it to negotiate the groove. Each instantaneous change, because it forces a change in velocity at the stylus tip, is an "acceleration". Acceleration is defined as a change in velocity, up or down. So now you have a mass (the moving mass of the cartridge) that is constantly accelerating. This would create or rather require the stylus to endure tiny forces according to Newton’s First Law of Motion (F = ma). It is those tiny Newtonian forces, which have a vector direction in the general direction of the friction force, that add to the net skating force.

Then could you explain why if you put the stylus on a glass platter or blank vinyl disc, neither of which have a tortuous groove, the skating force still occurs ? 

Sure.  Nowhere did I or anyone else say that groove tortuousity is the sole cause of the skating force.  In fact, I think it's a minor factor causing minor ups and downs of the baseline skating force, which is due to friction of the stylus in a vinyl groove. 

Skating force is due to overhang. No overhang, no skating force. That simple. This is why tangential tracking arms have no need of anti-skate. Tracking tangentially generates no skating force. 

Once there is overhang then there is skating force, but only when playing a record. This is so obvious it should go without saying. But someone keeps insisting otherwise. If the velocity is zero, there is no skating force. If there is velocity with overhang then there is skating force. Clearly then skating force is related to velocity. QED.

"No overhang, no skating force." Wrong. Underhung tonearms produce a skating force except for the one instant that the cantilever is tangent to the groove (the single null point that one can achieve with an underhung tonearm). Haven’t we been through this before? All pivoted tonearms produce a skating force. So if simplicity of the explanation of skating force is your goal (as simplicity is usually your goal), and if you don’t like "friction", then you can say "no pivot, no skating force". 

Also, for the Nth +2 time, speed of rotation per se is not a factor, once the LP is spinning.  If it were, wouldn't skating force get much worse when you play a 45 rpm LP vs  33 rpm LP? And wouldn't the skating force be much worse at the outer grooves of any LP vs the inner grooves? Please read my post a few posts up from here.  I could be wrong about how groove tortuosity adds and subtracts from the net skating force, and I would be happy if you can point out where and why.  Some things actually are complex and resist attempts to simplify.

Gentlemen, I am both enjoying and learning from this discussion. I wish that I had the mind to understand all of it. I am not joking. Discussions like this are valuable to me in other courses of mechanics. 

 It would be easy to assume one point of the discussion to be the end all, and then someone points out an overlooked fact and the discussion must either accept or deny the viability of that fact.

  Much appreciated from this reader. All the best>

@lewm , call it whatever you like Lew but the "pull" on the stylus increases with groove velocity (modulation). It is usually referred to as friction but I understand your distinction. According to the equation the kinetic coefficient of friction changes with groove velocity which results in the variation in skating force. Groove velocity does not change over the surface of the record which is why the skating force does not change much over the surface either.  

@lewm, you are right that the linear speed of the record by the stylus which decreases as the arm gets towards the center of the record does not change friction. Thus if you had a blank record the friction would be the same anywhere on it.

Although it is termed as friction, as groove velocity increases more energy is required to keep the stylus moving. The stylus has to be accelerated harder which would increase the force the groove places on the stylus which would increase friction. This happens momentarily as the stylus is forced to change direction but the additive effect is to increase friction.

Overhang has almost nothing to do with skating unless you play the label area. It is almost purely the result of a pivoted arm having an offset angle. Decrease the offset angle and the skating force decreases. A straight arm has no skating. There is a relationship between tonearm length, offset angle and overhang but an offset arm will skate even if the overhang is zero. Try it millercarbon. Set your tonearm so there is no overhang and play a blank disc with your anti skating defeated and watch what happens. 

@dover , The skating force you see on a blank disc is due to raw friction, as Lew understands it and the offset angle. The pull on the stylus is the result of friction plus the energy required to change directions which increases with groove velocity. That "pull" is the kinetic coefficient of friction in the equation above.

Mijostyn, I would take issue with a few of your points, but I will settle for this one as being the most egregious: "According to the equation the kinetic coefficient of friction changes with groove velocity"

Please show me that equation from a reputable source. As you are probably tired of reading, I have been saying over and over again that the friction force is independent of velocity, once the stylus is "moving". I only base this statement on every single physics reference I can find. So I need to see a reference to refute the notion. For all objects at rest, there is a quantity some call "stiction" or static friction, which is a way of saying that you need to put in a bit more energy than just enough to overcome friction, in order to get a body moving from rest. But otherwise, all is "kinetic". So there is no need to stipulate "kinetic".

On a separate note, I agree with MC that overhang does have a lot to do with the skating force, as it, combined with headshell offset angle, results in a constantly changing net Tracking Angle Error across the surface of the LP. Without the constant variation tracking angle error contributed by overhang, total TAE would be a constant, because the headshell offset angle is constant. Therefore, the skating force would be a constant, excepting the effect of groove tortuosity. Even at the putative two null points that can be achieved with an overhung tonearm with headshell offset, there is still some skating force. THAT skating force IS due only to the headshell offset angle, for those two instances in time. Underhung tonearms (which never are built with headshell offset angle, in my experience) do give zero skating force at the single null point available with such a tonearm, thanks to the absence of headshell offset angle. At the null point, underhung tonearms behave just like a SL tracker.

My experience is that anti-skate depends from the cart used. Those

with low compliance will need anti-skate those with high compliance

will not. I don't use anti skate with carts which can reach 60 microns

tracking ability test. 

 I don't use anti skate with carts which can reach 60 microns

tracking ability test. 

Perhaps you could save money by asking a retipper to turn the old stylus around so you can wear the other side out before you put a new one in.

@lewm ,  whether you like it or not lewm the skating force increases with groove modulation which is synonymous with groove velocity. I have explained it as best I can to get it through your stubborn countenance. Maybe AJ Conti can do a better job.   https://www.basisaudio.com/ajs-discussion-of-antiskate-forces/  You continually want to mistake groove velocity for linear speed. They are two very separate granted loosely related issues. There are only two coefficient of friction figures for any pair of materials, static and kinetic. The static coefficient of friction is related to the two materials in contact at rest which includes the "stiction" factor. The kinetic coefficient of friction is related to the two materials in motion which is the situation we are dealing with. The kinetic coefficient of friction does not change with linear velocity or what you would have playing a blank record, but it increases with increasing groove modulation which is synonymous with groove velocity. You object to the term groove velocity because it includes the word "velocity." When you see the term "groove velocity" just substitute groove modulation and I think you will be just fine. If not you can object until you are blue in the face but it won't get you anywhere except maybe a visit to the ER and I certainly do not want that so please do not stop breathing. We like having you around to argue with.    

@nandric , while the skating force might change a tiny bit with stylus profile, other than the prescribed VTF the cartridge has nothing to do with the skating force. 

Don't ever deny what dover states because he get angry. 

@nandric 

Where's your sense of humour ? 

Dear dover, it is called ''professional deformation''. I thought that we have
dispute and I am ''professional lawyer'' . If I lose nobody will hire me.

@nandric

So you think if you lose an argument on an audio forum, then no-one will hire you as a lawyer. Perhaps some of your recommended reading on philosophy, reason and logic might need to be revisited.

My way

At the risk of death by fire, I venture into this conversation as you both have points that are correct and some that I would address differently. 

There are many factors that cause skating force. Even a pivoted linear tonearm experiences skating force - albeit in both directions depending upon the playing radius and at a skating force at worst case at about 40% what a standard 9" arm would experience. 

Offset angle has nothing to do with skating force. You can watch my very quick and dirty videos showing this to be true HERE. (It's not terribly professional and I'd demonstrate it differently today but who has the time?!) However, because offset angle is directly related to overhang, one would be excused for being confused on this issue. Yes, underhung arms will exhibit skating force too, but the force will be in the opposite direction!

We should make the delineation between linear groove velocity (which I don't think mijostyn was talking about) and groove amplitude which is measured in velocity (usually cm/sec). Some firms describe this in microns where they measure the distance from the peak of the groove undulation to the centerline. Thus, Ortofon's 80/90/100micron torture tracks are actually double those figures in horizontal travel. A Lyra stylus is only about 100 microns wide. Think of the total excursion at frequency! That much velocity is unhelpful as a test track, IMO, and will cause too many unnecessary returns of cartridges to the manufacturer.

Make sure you download the attachment at the bottom of the article mentioned above. Skating force is determined by the Effective Moment Arm and the coefficient of friction between stylus and groove. Both are required to create a skating force. As you can imagine from the drawings in the download, Effective Moment Arm exists in pivoted linear trackers too.

The blank record method is highly variable based upon many things such as: radius test is done at, types/quantity of plasticizers in record, profile of VERY tip of stylus, zenith error, etc.

We have all the equipment to do coefficient of friction testing and intend to write the first publication on this since the 1960's, but zenith error studies come first as they are more impactful on sonic performance than confirming modern vinyl formulations and stylus tip profiles have substantively changed the recommended setting for anti-skating.

HERE is an interesting experiment in friction. Following a translation, we were able to calculate that ~10% of VTF is still the right target for anti-skating. The test needs to be more robust to be sure. Stay tuned for that...

Thank you. The method in my video is a starting point and most it is ok. I also measure distortion with Adjust+ on each channel and phase identity.

To measure the as-force out of the groove i test this

https://www.briefwaage.eu/shop/my-weigh-jim-federzugwaage-stiftwaage-5g.php

Dear dover, who pretend to have ever won any argument ''against''

me? You are only stating  an hypothetical case. 

Dear Mijo, I never said the skating force was not affected by groove modulation. In fact, I agreed that it IS affected by groove modulation, which I described as “tortuosity”. My objection was to your repeated insistence that velocity or speed affects the friction force. It does not. Not because I say so, but because the equation for friction force says so. Thus we have to find another mechanism for the effect of groove modulation on the skating force that does work with accepted theory. I described two possibilities: (1) groove tortuosity causes momentary acceleration of the cartridge moving mass that also pulls the arm inward, adding to the skating force, and (2) Groove tortuosity causes mistracking. Mistracking causes momentary variation in VTF. VTF does affect friction and the skating force.

Wally, It is my impression that underhung tonearms elicit a skating force in BOTH directions.  The force changes direction (where by "direction" I mean toward the spindle vs away from the spindle) at the single null point, where for one magical moment, there is zero skating force. So if you made a graph of the the skating force across the surface of an LP, for an underhung tonearm, you would get a straight line, give or take, that starts on the positive side of the X-axis, passes through zero at the X-axis, representing the null point, and ends up on the negative side of the X-axis.

Also, is it not the case that headshell offset angle does produce a skating force all by itself, at each of the two null points for an overhung tonearm, where the stylus is tangent to the groove but headshell offset still produces skating force?

Hi lewm,

Study the Effective Moment Arm in the download. Imagine how it would be drawn if the stylus were underhung at various radii. Your answers should be there! By the way, drop the idea of null points having a significant influence on skating force. If they did, a graph of skating force (independent of changes in coefficient of friction) would not be a parabola but more of a "W" shape with the lower Y-axis points in the graph sitting at the null points along the X axis.

So: drop thoughts of null points and offset angle. Think only in terms of Effective Moment Arm (look closely at how it is drawn/determined) and coefficient of friction.

Hi ninetynine. Measuring anti-skating force using a multivariate test as it seems you may be doing with a test record and an analysis of the electrical signal is fraught with many problems. Like a mosquito at a nudist colony beach, I'm not even sure where to begin!

Measuring crosstalk is the one and only multivariate test that I will allow done - and only because there is no alternative. This is because SO MANY things need to be right before you can trust the validity of the data you get from these multivariate analyses.

However, I have done a study of the cutterhead stylus alignments on the azimuth axis on 9 different test records and can confidently report that this industry is a bit of a mess. This industry has the technology to make styli that truly replicate the cutterhead stylus contact profile (Shibata was NEVER one of those) and equipment that can reveal the finest iota of information from the groove when all parameters are in alignment, yet the engineers making our test records - that we must trust to use to align our styli by - can't agree with each other by a factor of several magnitudes of unforgivable. We will be releasing data in our own study soon. 

I think we’re talking past each other. But I’ll take a look at your attachment.

Regards:

Published to AES, 1967: "The Skating-Force Phenomenon. What it is, how it's measured, and its influence on performance of modern, lightweight phono cartridges." JAMES H. KOGEN ...

6 pages

PDF, copy/paste Google search:  "1967 paper by Shure’s Chief Engineer James Kogen." 

Found at audio-creative.nl. 

* Skating decreases towards the spindle as centripetal force (est. influence  elsewhere @ 5%) increases.

* Downforce, stylus profile, depth of groove and groove velocity are factors. (Spindle to pivot distance is a consideration.) 

* Increasing or decreasing skating force will influence wear to either inner or outer grooves, as well as wear to either the left or right bearing surface of the stylus. 

(Wallytools- Shure devised a neat tonearm mounted device to measure skating. It's described in the Kogan paper.)

Conrad Hoffman has thoughts on the subject, http://www.conradhoffman.com/AntiSkate.htm

Descartes on First Principles: "It will accordingly be necessary thereafter to endeavor so to deduce from those principles the knowledge of the things that depend on them," Although Descartes never spun an LP it is likely the philosopher would agree that although it might fit many, one shoe doesn't fit every foot.

When skating is balanced, left and right channels are hypothetically equally amplified. The "phantom center channel" phenomena emerges. Very minor adjustments to anti-skating will move soundstage center left or right.

Through the early 1970's, VTA at 15* was typical. Sometime around 1974 (IIRC) 22* VTA as standard was agreed on. Later investigation found there was still a discrepancy of several degrees VTA/SRA from one manufacturer to another.  As with correctly aligning an advanced profile stylus, azimuth or SRA may vary. Stylus to cantilever fitting is not always precise. Setup by the book is sometimes an approximation, none the less a good place to begin. Presuming ones gear is in good condition, listening and knowing what to listen for should confirm the best practical application. 

Peace,

Timeltel, it’s great to hear from you. Hope you’ll stay around.

what with all it’s problems, drawbacks, and impractical aspects, it’s a wonder how good vinyl can be.

Dear Wally, From your excellent videos (excellent in terms of clarity and presentation), I get that when the line from the pivot to the stylus is perpendicular to a line drawn on the radius of the LP, there will be no tracking force. That is exactly what happens at the single null point one can achieve with an underhung tonearm. I also get your evidence that headshell offset angle has nothing to do with the skating force, but that is shown for a spherical stylus on a groove-less LP. (By the way, where did you get what appears to be a Columbia 6-eye LP with no grooves?)

Have you repeated the experiments with either a non-spherical stylus or an LP with grooves, say a 1kHz steady signal? I realize that with grooves one would not so easily be able to visualize the skating force. As to the video in Russian, the set-up is cool but the dialog is unintelligible to me.

Where did I miss your definition of "Effective Moment Arm"? I haven’t a clue.

From the point of view of pure physics, I still don’t see why an overhung tonearm with an offset headshell, aligned according to any of the popular algorithms, would not exhibit a skating force at either of its two null points that is for that moment due only to headshell offset angle. Maybe you need grooves and/or a non-spherical stylus tip to show that. I do agree with you that a lot of so-called authorities have run to far with that ball, saying that headshell offset is THE cause of skating, which I agree it is not.

Regards Lew(m):

Thanks for the gracious "hello".

You wrote: "a lot of so-called authorities have run too far with that ball, saying that headshell offset is THE cause of skating". I too have heard that. One might ask those audio gurus what would be the effect if the headshell were turned away from the spindle, would then skating force direct the arm away from the label? An amusing proposition. 

It seems to me that no matter which point of the compass the headshell is aimed or however the tonearm is configured, the axis from stylus to pivot (and as you mentioned, over/underhang) is the primary  consideration.

Peace,

Answers to Lewm and timeltel questions are HERE. Be SURE to download attachment at bottom of page.

There is no centripetal force vector that consistently aims toward the spindle. It has been a long time since I read Kogen, but if he claimed the existence of centripetal force in skating then he either was referring to a condition similar to the one in my first slide of the download (depiction of the treadmill), which is a minor component of skating force, or he used the term in a figurative sense, not literal.

The profile of the very tip of the stylus will have no impact on the force vector directionality but may have an impact on coefficient of friction.

By the way, Wally passed away in 2018. This is J.R. Boisclair. I did not use my name as my moniker not because I am "hiding" but because I felt I should make it clear that I have a direct interest in this industry and it would be best if you knew who was doing the posting. Most people know WallyTools and fewer know my name. Cheers!

Agree, centripetal force, in the Newtonian sense, is not the issue.  I am aware that the "real Wally" passed away a few years ago. I just figured "wally" was a reasonable way of indicating that I was responding to your post.

Hi Wally, i can measure with Adjust+ the harmonic distortion with a 1kHz tone (0dB - 11,3cm/s) Does it make sense to adjust antiskating for identical distortion on both sides? Does 11,3cm/s this corresponds to normal music level?

I am bewildered. Several points made defy logic.

Antiskating has nothing to do with offset angle? I suppose you could say that the skating force is due to proper tonearm geometry of which offset angle is one factor.

A straight arm with no overhang has little skating when it is tangent to the groove.

A 12" arm with a smallish offset has a lesser amount of skating than a 9" arm with more offset. 

The water skier outside the wake has created an offset angle. If Wally wants to look at it from a different angle, it is a free country, but looking at it as a function of offset angle is perfectly appropriate.

Poorly set antiskating does not affect the volume of either channel and does not move the center image. It effects the groove velocity at which the cartridge will start miss tracking one channel or the other. Miss tracking causes distortion, very annoying distortion.

Boy, is it cold outside! Don't forget your gloves and hat!

My buddy in Burlington VT told me what you guys are expecting today. Wind chill of -25 degrees. I don’t own a coat for that. I am vacationing, if you can call it a vacation when you are already retired, at our house on the island of Vieques off the coast of Puerto Rico. The daily high temperature is about 85 and the low temperature is about 72. The beaches are beautiful and mostly empty.

An underhung tonearm all of which have zero headshell offset will have zero antiskate when stylus/cantilever are tangent to the groove or perpendicular to the LP radius in Wally terms. As for the effect or lack thereof of headshell offset angle in an overhung tonearm, I just took Wally’s conclusion at face value, that the demonstration applies for a spherical stylus on a grooveless vinyl surface. For me, that is just another reason not to set anti-skate using a flat vinyl surface with no grooves.

@lewm , I would say I am jealous but I just bought a new set of ski boots and skis. In this cold weather the ski areas can make snow like crazy. One good storm and we are all set. I have to justify the expense:) 

Do you have another system in your tropical abode?