Stylus force digital scales

Folkfreak, There are many digital scales on the market that feature non-magnetic weigh pans.  You are quite correct that any scale with a ferrous weigh pan would give an inaccurate measure of VTF and might even result in damage to the cartridge suspension.  However, as noted, this problem is easy to avoid.

cleeds, True, gravity is a constant for any particular location on earth, however, actual VTF will vary depending upon where the tonearm is located in its vertical arc.  This happens when you play a warped LP, for example.  Thus it is important to use a scale that allows VTF to be measured at least roughly in the same plane as that of the surface of a typical LP.  There would be a tiny variation in VTF, depending upon thick or thin LPs, not enough to worry about in my opinion.

Chakster, Like Raul often says, Relax and enjoy the music.  As many papers as there are on using a digital microscope to set SRA, it is nevertheless a skill that can only come from doing it regularly under the guidance of one of the very few experts in the field.  I advise you to do it by ear.  Azimuth is yet another can of worms.

@lewm funny thing is I even find this with audiophile approved scales with non ferrous pans. They record exactly the same with a static weight like a screw but once I load them with a cartridge they’re all over the place. Could it be that the strong magnets in a cartridge affect the mechanism not just the pan? Anyway I trust the design of the Rega (just like the cartridge man scale I owned before, although that was really prone to breaking down due to its battery design) and it’s one thing I no longer need to worry about

Thanks chakster, lewm and folkfreak, very informative.
As folkfreak points out, even scales with non ferrous plates can have inaccurate readings due to strong magnets of MC carts affecting the whole mechanism. That would explain little increase in values with my DS-3, I strongly believe now.
I will try the plastic Rega scale, thanks again for great input.

lewm

... gravity is a constant for any particular location on earth, however, actual VTF will vary depending upon where the tonearm is located in its vertical arc.  This happens when you play a warped LP, for example

Varying VTF while playing a warped record is the result of dynamic forces. What we're talking about here is static VTF, which does not "vary depending upon where the tonearm is located in its vertical arc."

Also, if you use a dynamically balanced arm, VTF will remain constant even while playing a warped record.