Kuzma 4Point vs Airline - is it worth the upgrade?

Syntax, the 4Point is not as you describe. Perhaps there was a gross mismatch with the cartridge, or maybe the cartridge was poorly set up or imcorrectly loaded. Big, bold, dynamic, tonally rich, low noise, and nuanced are what my customers and I hear. But don't take my word for it: certainly in this price range one should pursue an audition.

Dealer disclaimer.

Jfrech: Two bearing points are the horizontal plane and are permanently hidden, and two points are in the vertical plane. The latter are clearly visible and are akin to two inverted unipivots. It's obvious when you see it.

Kuzma dealer.

Hiho, thank you as well. The photos are very helpful.

Dover, the comparison of two points with a knife edge is flawed since the force is concentrated at two points, not over what is presumed to be a line but due to machining accuracy and tolerances cannot have the forces uniformly distributed.

The Morch DP6 tonearm is a two point bearing design and one spike/cup is height adjustable in order to change azimuth. Perhaps the set screw on the spike of the Kuzma 4Point is for that too.

Adjusting one of the spikes to adjust azimuth has some problems. For one, it is a relatively crude adjustment. For another, adjusting it would very slightly increase or decrease the distance between the points (Pythagoras' theorem).

The 4Point azimuth adjustment is accomplished nicely via the grub screw in the bottom of the arm tube which is perpendicular to it, seen in the photo of the upside down arm for the purpose of showing the vertical bearing spikes. The section of the arm tube near the pivot is about 1 1/4" long, to which the rest of the arm tube is attached. Very fine azimuth adjustments are possible.