Fidelity Research FR-54 Tonearm. ANTI-SKATE???

Yes the skating force is due to friction between stylus and vinyl groove.It therefore stands to reason that the size of the contact patch afforded by different stylus shapes would affect friction and therefore affect the skating force and therefore affect the amount of anti-skate required.

On mono LPs the audio signal is encoded on the horizontal only. Any vertical deflection of the stylus is canceled using a mono cartridge. So it’s not a good idea to use a mono LP and cartridge to set AS if you’re then going to use the same setting for stereo. But I confess I don’t precisely know offhand what you would hear with a mono LP and a mono cartridge and aberrant anti skate. 

Unfortunately, the anti-skate force is never exactly right from one second to the next. So to some degree I share the notion: forget about it, unless you are hearing gross distortion in one channel or another, which you noted. And you did the right thing to correct that. NOW you can forget about it.

 I would never challenge the result of your listening tests. I am happy that you have arrived at what appears to be a satisfactory amount of anti-skate. However, please don’t deny the laws of physics. No matter how many grams you put on the end of your string, the resulting AS force at the stylus tip will be much less, in grams. What you have really demonstrated is that the amount of AS needed is much less than the VTF, in grams. A few other people besides me mentioned that at the beginning of this thread. 

Mijo, Way up the thread, Elliot wrote, "Well, it sounds darn good 1.5g down/2.5g out, but I don't have any experience with playing Mono LP with Mono Cartridges*; This Cartridge; This Arm."  This was at the point where Elliot assumed the 2.5g weight was creating 2.5g of AS force, but that doesn't matter.  Where did he say that with 2.5g weight at that VTF (1.5g), the stylus drifted outward in the run-out groove?  If that's the case, it's odd that apparently excess AS sounds so good. Are you really denying the physics of the thing? (I mean to say that the 2.5g weight must deliver much less than 2.5g of AS. I can make no claims regarding how his particular set-up might react.  I can imagine that for his particular stylus shape, whatever that is, he may need even less AS than he has now.)

Don’t believe me. Believe Archimedes and Isaac Newton.  Oh, and you could choose to believe the guys who discussed the FR54 on one of those other forums, when they concluded the AS mechanism delivers an AS force about right in magnitude for a 1.5g VTF.
And how do you plan to "test" (the amount of AS force, presumably)?

"I have a hard time believing 2.5g weight is giving only 1.5g outside force, especially as it attaches 1/2" forward of the pivot."
Please consult the Wikipedia page on levers.  The 2.5g weight is going to provide much less than 2.5g of side force precisely BECAUSE it attaches to the arm wand so close to the pivot. We are concerned with the force generated at the other end of the arm wand (the lever), at the stylus tip.  Work is Force (F) acting over a distance (s).  W = F*s. According to laws of conservation of Work, the Work done by the dropping 2.5g weight must equal the Work done on the stylus tip (with minor losses due to friction).  So, notice that the length of the arc traversed by the arm wand at its attachment to the string, as the string and weight drop, is much, much shorter than the length of the arc traversed by the stylus tip as it goes across the LP surface.  Call the two distances s for the AS device and S' for the stylus tip.  Because Work or Energy is conserved, F*s = F'(the AS force on the stylus tip)*S'. Because s<<S', then F'<<F.  The force at the stylus tip must be much lower than 2.5g.

I did some research for you.  The manual IS available on Vinyl Engine but only in Japanese.  However, there are several older threads on this tonearm that are also mostly to be found on VE.  The consensus seems to be that your impression is correct; AS is not adjustable.  On the other hand, several persons agreed that the single weight provided gives approximately correct AS for a VTF = 1.5g.  So, you should be fine.  In future, you might check VE for answers to questions like this one. I found no evidence that FR ever provided a set of weights to accommodate different VTF values.  Apparently, Mr Ikeda was not obsessed with AS.

I’ve never seen an FR 54, so I have no comment on its particular AS mechanism. My only point was that because the anti-skate weight itself weighs 2.5 g is not sufficient data to conclude it is putting 2.5 g of anti-skate force on your tone arm.  The net anti skating force might will be less than 1.5 g which is your VTF right now.  I suggest you examine the tonearm more closely. Maybe there is a way of changing the angle of the string, which also would change the anti-skating force. Also I would check the manual that was once provided with the tonearm. If there indeed were various anti-skating weights for different VTFs (something I’ve never heard of), it should show up in the manual. If it does not show up, I think you are just missing something . I am actually surprised that by now some other owner of an FR 54 hasn’t chimed in to explain what’s going on. Perhaps you can find the manual on vinyl engine, if you don’t already have one.

To get you started, an AS device creates a class 3 lever. Where the tonearm is the lever, the pivot is the fulcrum, and the cantilever is the load.  See here: https://en.wikipedia.org/wiki/Lever
That's if the AS force is applied to the arm wand.  In some cases, the AS force is applied to the short arm that holds the counterweight, to the rear of the pivot, and the AS force pulls the short arm inward.  In that case, we have a Class 1 lever.

 The force with which the anti-skate weight is pulling outward on the tone arm is related not merely  to the weight in grams of the AS weight itself. It’s also dependent upon the distance of the connection between the weight and the arm wand from the pivot point. it’s a lever in principle. So if you can get out your old geometry text you can figure out how much AS force is actually pulling on your arm. And you don’t want so much as a 1.5g AS force for a 1.5g VTF. Much less will usually do.