Oops I sent before done. To continue - it doesn't matter AT ALL if the scale is accurate on an absolute basis. All that matters is that its results are nearly identical over multiple passes (repeatable). Because ultimately, if you're going to set up a table really right, the VTF that you measure is only a starting point and later a reference point.
Every cartridge/tonearm/table combo has different characteristics (not to mention interplay between VTF and anti-skate settings), so the manufacturers' VTF recommendation is just a rough estimate which becomes immediately irrelevant. You'll ultimately adjust VTF up and down BY EAR until it SOUNDS AND TRACKS BEST. and then you'll re-measure with the scale to note the result ONLY so you have a reference for when you need to reset the VTF later - e.g., your cartridge suspension has softened up. But that's all - the scale by itself only serves as a somewhat random starting point even if it's accurate to a gazillionth of a gram.
(Nor does it matter, as has been speculated here, whether the arm is in it's exact vertical "playing" position. Do an experiment if you'd like - lift your scale up on top of an old Mariah Carey lp with a couple of quarters and watch how much the VTF changes. Not much - it's a simple vector calculation.)
Every cartridge/tonearm/table combo has different characteristics (not to mention interplay between VTF and anti-skate settings), so the manufacturers' VTF recommendation is just a rough estimate which becomes immediately irrelevant. You'll ultimately adjust VTF up and down BY EAR until it SOUNDS AND TRACKS BEST. and then you'll re-measure with the scale to note the result ONLY so you have a reference for when you need to reset the VTF later - e.g., your cartridge suspension has softened up. But that's all - the scale by itself only serves as a somewhat random starting point even if it's accurate to a gazillionth of a gram.
(Nor does it matter, as has been speculated here, whether the arm is in it's exact vertical "playing" position. Do an experiment if you'd like - lift your scale up on top of an old Mariah Carey lp with a couple of quarters and watch how much the VTF changes. Not much - it's a simple vector calculation.)