Is my anti-skating too strong.

@mijostyn

Actually I do run a linear tracker - Eminent Technology ET2

Not an English major, but understand force vectors - studied Engineering at University. However, most of the english on this thread is such poor quality, it is the very reason many are arguing the same point from opposite sides of the tangent, or debating at cross purposes.

You blank record analogy is false.

If you understood what a tangent is, you would know that the null point is momentary in time is the stylus passes through ( assuming the record is spinning ) with a pivoted arm.

When the stylus is tangent to the groove (null point) the pulling force caused by the friction with be inline with the tonearm’s linear offset, thereby causing a rotational torque around the tonearm’s pivot.

The forces are far more complex than you posit. The primary force (drag ) is on the stylus/cantilver, not the arm. As the stylus passes through the point tangent it is momentarily pulling the cantilever in a straight line. Yes, you have a hinge between the cantilever/elastomer and the arm, but this gets very complex if you want to model that. Furthermore you need to factor in whether the arm bearings are offset, and what sort of cartridge cantilver mechanism is in play.

This is why it is much more prudent the eyeball the cantilever under dynamic conditions to ensure it is remains straight and is not getting pulled one way or the other. Using formulae and theory to set antiskate is not the best in my view.

If you talk to cartridge retippers such as the original Garrot Brothers and AJ van den hul, they will tell you most cartridges they reveive have uneven wear arising from incorrect antiskate settings.  

For the record not only do I run a linear tracker, but also a cantileverless cartridge - Ikeda Kiwame. Antiskate arguments are moot.

As an aside, when I had a hiatus from audio tinkering some years ago, I ran a high compliance Shure V15vxmr in the ET2 for 10 years. The cantilever was still dead straight after 10 years of running, despite the high horozontal mass of the ET2. 

It is a bit confusing that some posters are saying that overhang or offset angles "cause" the skating force.  The WallyTools videos posted here that shows that, under specific conditions, skating forces can even be in the opposite direction, add to the confusion because they do not attempt to explain why this is so.  Overhang and offset angles don't directly "cause" skating forces, but, they do create the conditions that give rise to skating forces because they create the geometry that causes the force of friction (drag) to pull the arm in one direction or another.  

The drag developed at the point of contact of the stylus with the wall of the groove is pulling along a line that is a tangent to the points of contact of the stylus.  Whether this tangent is in the same direction as the cantilever or to the left or right of this line is dependent on the alignment of the cartridge at that particular moment.  For a reference point, imagine that a spherical stylus, when viewed from directly above, is a clock face with the axis of the cantilever bisects the 6 o'clock and 12 o'clock position.  When that stylus is at a point on the record where the contact is at the 9 and 3 o'clock position, the drag is directly along the line of the cantilever.  Will this result in skating force?  The answer is:  it depends.  If the alignment is such that the cartridge is perfectly straight (no offset angle to the headshell and cartridge), at that perfect tangency point on the record, there is no skating force because that drag is pulling straight back to the pivot point of the tonearm and that pivot is resisting that drag.  But, if the alignment is a conventional alignment, such as Lofgren B, at the point of perfect tangency, there is a substantial skating force, because the drag along the same line as the cantilever is pulling at a point to the right of the pivot point (because of the offset angle) and the pivot cannot completely resist that pull.  On the setup with a cartridge facing straight forward with no overhang, at points outside of the perfect tangency point on the record, the points of contact will not be at the 9 and 3 o'clock position, but something toward the 10 and 4 o'clock position; this means that the drag direct (tangent to these points) is aimed to the right of the pivot and so there is skating force.  At the point inside the point of tangency, the points of contact are toward the 8 and 2 o'clock position, so the direction of drag is to the left of the pivot an the skating force is now in the opposite direction.  The reason there is ALWAYS a skating force in the conventional direction with conventional alignments (e.g., Lofgren) is because these alignments minimize the deviation from perfect 9 and 3 o'clock contact (always less than 2 degree deviation) which is MUCH less than the fixed offset angle; this means that the drag is ALWAYs to the right of the arm pivot point even if does deviate over the diameter of the record.

@dover, good thing because the forces acting on the tonearm cartridge system ( they are imminently attached to one another) are very simple. 
But since you Mention the Eminent Technology arm, it is a rip off of the Walker Proscenium arm. Both are arms in search of a cartridge that does not exist. The cartridge would have to have three times the horizontal compliance in relation to vertical compliance. Thus both arms exhibit much more distortion than proper pivoted arms. Air bearings are simple devices. You can easily buy a bearing and make your own air bearing arm more easily than you could make a gimbal pivot arm. Companies like SME or SAT could easily make air bearing arms but choose not to for good reason. The distortion added by tracking error is far less than what is added by an inordinately high horizontal effective mass. Linear trackers with motorized carriages are superior but difficult to design and build, far beyond a company like Eminent Technology or Walker. Better yet are arms like the Reed 5T and Schroder LT. Both arms have secondary horizontal bearings, one motorized the other magnetically guided that otherwise function as normal pivoted arms. They just stay tangent to the groove but, more importantly do not generate any skating force which is even more important from a tracking perspective. IMHO the Schroder LT is a brilliant design powered by the pull of the record on the stylus which transfers it to the cantilever, which transfers it to the cartridge, which transfers it to the tonearm and finally to the bearing platform pulling it forward while a magnet keeps the arm properly aligned. Brilliant. I wish I were that smart.

@mijostyn

But since you Mention the Eminent Technology arm, it is a rip off of the Walker Proscenium arm. 

Unfortunately your comments on the Eminent Technology tonearm are wrong and ill-informed.

Bruce Thigpen, the designer and owner of Eminent Technology products, was the designer of the old Coloney/Mapleknoll  air bearing turntables and tonearms. Bruce moved on to form a new company and developed the Eminent Technology ET2 and other products.

Lloyd Walker took over the Coloney/Mapleknoll turnable business and designs and then developed the Walker Proscenium TT's from Bruces early designs. The Eminent Technology ET2 preceded Walkers own updates on the Mapleknoll TT's and air bearing arms.

Both are arms in search of a cartridge that does not exist. The cartridge would have to have three times the horizontal compliance in relation to vertical compliance. Thus both arms exhibit much more distortion than proper pivoted arms. 

The ET2 is far more sophisticated than the Walker arms. The patented decoupled counterweight, adjustable VTA on the fly using an arc block so that vertical pivot to stylus stays constant regardless of VTA position remains. As far as I know it is the only arm linear or otherwise that accomplishes this.

With the counterweight decoupled the horizontal effective mass of my ET2 is well under 20g, Thats less than many current heavyweight arms.

The decoupled counterweight in the horizonal plain ensures that the arm has different effective mass horizontally and vertically - similar to the Dynavector arms - which results in a substantially reduced peak resonance in the bass.

Your comments above on compliance and distortion are ill informed - you clearly have no understanding of the ET2 design. The effective masses both vertically and horizontally can be tuned individually to the cartridge via adjustable weights/position of weights on the I beam & variable decoupling rates.

The Walker has none of these features.

With regard to air bearing arms with motorised carriages - you can see them crabbing across the record - they dont work. I've worked with both.

If you want to get into Thales etc - well they have their own downsides - due to their design they lose rigidity thorugh their complexity - not the best way to measure the groove with a rattly arm. 

It is just like unipivot versus gimball bearings - there is no best - simply pros and cons of each design.

You mention Schroeder - his Reference arms hanging on a piece of string do not provide a stable platform for the cartridge. They are a joke. 

You should spend more time reading up on arm designs, it will help you optimise your own turntable regardless of which arm you prefer.

Thank you Dover.  Finally someone who understands the principles and issues attaching to different arm designs.

Horizontal effective mass of a parallel tracker can inherently be much less than a pivoted arm.  Many parallel designs have arm tubes that mimic a pivoted arm because designers lack imagination and do not start with a clean sheet.  The stylus need only be two or three inches from the sliding bearer.  See Simon Yorke Aeroarm.
Dover, please note Aeroarm has adjustable VTA on the fly.

Yes, motorised carriages are nonsense.  They cannot constitute a low-friction bearing and will always cause drag or pull on the stylus in the groove.

Well engineered air bearings are very low friction, potentially far lower than gimbal bearings on pivoted arms.  Positive design features are very accurate machining - Aeroarm has a 5mu air-gap.  And vibration-free high and constant air pressure to fill the air-gap and keep the bar and tube in a steady-state relationship and not impose jitter or eddys.  Operating theatre compressors aren't cheap but do an excellent job.  They should be sited in a different room, a long way from the TT.  Don't use fishtank compressors, even big ones.

It is fundamental to prevent the stylus moving relative to the TT chassis, save as driven by the groove walls.  All other movement is other than what is in the groove and will be transmitted as distortion.

So pivoted arms hung on strings are utter nonsense.

Unipivots are also inherently unstable in that respect, so difficult to engineer.  Damping will tend to cause drag, although nearly all are damped, usually with liquid or gel.  The only solution is to site the pivot high relative to the record surface, but there will still be a tendency for the contraption to swing and allow the stylus to move from lateral perpendicularity in the groove.  Even a little of this is VERY bad.