I noticed the same thing on my Nighthawk arm, and Richard at Supatrac told me that this is simply abrasion of the ceramic paint on the surface of the "thrustbox'' at the pivot point and is normal. Neither the pivot screw nor the metal of the "thrustbox" itself is being abraded. And most important, I have heard no evidence (from playing records) that this phenomenon has degraded sonics.
I noticed the same thing on my Nighthawk arm, and Richard at Supatrac told me that this is simply abrasion of the ceramic paint on the surface of the "thrustbox'' at the pivot point and is normal. Neither the pivot screw nor the metal of the "thrustbox" itself is being abraded. And most important, I have heard no evidence (from playing records) that this phenomenon has degraded sonics.
Abrasion around the pivot contact area is normal. The steel thrust surface is 2.5mm thick so I expect the thrust box to last for hundreds of years. Remember that the bearing point does not bear the weight of the arm, so contact pressure is minimal and wear slow.
The pivot point itself is very easily replaced - even end users can replace it - so I expect that SUPATRAC arms are far less obsolescent than tonearms which have expensive, difficult-to-replace and fragile bearings which require extremely careful calibration. The pivot contact area is between the pillar and the thrust surface so you need to look for it to see it.
If the cosmetic aspects of your tonearm matter more than the performance then there are many visually-exquisite brands to choose from. My goal is ultimate performance, reliability and longevity. The Nighthawk's appearance is determined 99.9% by its function.
