Stylus Force Guages - why extreme accuracy?

In my opinion, you can do pretty good with a 0.01g accuracy scale from Ebay (search 0.01g scale, mine has a stainless steel platform. More exactly, mine is item #190001314544) and a little jig such as this which can be made for a few dollars. The jig ensures the VTF measurement is made at the record's height, which is important and something that the more expensive, record-specific scales do. I also have a 50g (half capacity) and 100g (full capacity) calibration weights for my scale. After calibration, in fact multiple measurements taken on various parts of the scale are really within 0.01g, which is why I recommend that particular scale. In addition, my dealer used a Winds scale on my turntable recently, so I had a chance to compare the two methods. Mine was about 0.08g-0.1g different from his reading. However, after using the calibration weights on the Winds, it looks like it was off about 0.05g (at least compared to the calibration weights..), so I'd say they're really close. Close enough, that it could be due to the heights where the two measurements were made. The Winds scale was placed on top of a record, while my method measured the plinth to record height, removed the record, and then calibrated my jig to mimic the previous record height. I used a steel ruler to measure, and IMHO my method was a bit more accurate at measuring VTF exactly at the record level.

I hope this is helpful!
-Marc

Most cartridge manufacturers have a recommended tracking force range, which allows for a bit of leeway plus/minus. I have used a Shure SFG-2 gauge for more than three decades, and have found it to be very accurate when checked against much more expensive digital gauges.

I am confused a bit by your comment about making final tracking force adjustments by ear. Are you referring to VTA (vertical tracking angle)? One DOES make final VTA adjustments by ear (after initially setting the tonearm to level), but I have never heard of making tracking force adjustments by ear. Seems to me that would mean there is no need for accuracy from the tracking force gauge.

Tracking force affects SRA, so adjustments by ear are important, right?:

I do VTA and VTF by ear. Use the gauges to get close. Ear for final dialing in....

Jfrech - Me too. Sdcampbell - may depend on your particular components, but on the tables and carts I've played with, lighter tends toward a more detailed sound and heavier toward a more romantic presentation. My by ear adjustments have stayed within the manufacturers recomended range but sometimes at the heavy end and other times toward the lighter.