A new way of adjusting anti skate!

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...

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. 

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!