The Woody String Bearing System

The Woody tonearm would be classified as a constrained unipivot with a short string bearing (a unique string bearing design) and viscous damping.

Unipivot tonearms can be classified as constrained and unconstrained. Unconstrained unipivot tonearms, a VPI arm for example, can dance around laterally during tonerarm handling and just after stylus touchdown.

Constrained unipivot tonearms handle like an arm with gimbal bearings. The constraint allows the arm to rotate a small amount about its axis, but snubs further rotation. The three constrained unipivot arms that come to mind are the Nottingham, Durand, and Woody arms.
 

The Nottingham arms uses a tricky internal nylon monofilament snubber system that I have never figured out.

The Durand arms have a lateral pin projecting horizontally from the armwand at the pivot. This pin is at right angles to the armwand axis. This pin bears lightly on a horizontal rail, preventing the armwand form rotating about its axis. Lateral balance is adjusted so that the pin barely touches the horizontal rail. The pin acts as a snubber. Adjusting the height of the rail adjusts azimuth. The most expensive Durand arm model allows azimuth adjustment on the fly.

The constraint system of the Woody tonearm is uniquely configured to allow adjustment of azimuth on the fly (while the record is playing). You can read about the Woody constraint system and azimuth adjustment on the fly at the following link: http://vtaf.com/id98.html .

There are several examples of string bearing tonearms, including the Well Tempered arm by Bill Firebaugh, the Frank Schroeder tonearms, the Clearaudio Concept tonearms, and the Woody.
 

The Well Tempered arms by Bill Firebaugh use a pair of long strings above the armwand. The string pair is twisted about 90 degrees, creating radial stiffness. An oil damper below the arm adds stability and damping. The Well Tempered arms are generally acknowledged to be tricky to set up and very fine sounding.

The Schroeder tonearms use a single long string above the armwand, and a strong magnetic attractor below the arm. The magnetic attractor adds lateral stiffness and electromagnetic damping. The Schroeder arms are generally acknowledged to be very fine sounding.

The Clearaudio Concept tonearm uses a powerful magnet above the armwand to lift the entire weight of the armwand system, with a wire below the armwand to resist the uplift of the powerful magnet.

The Woody uses a novel, compact, and unique string bearing arrangement above the armwand. The unique configuration of the bearing creates lateral stiffness and freedom to pivot. An oil damper below the arm adds stability and damping, and is incorporated into the azimuth adjustment system (which works on the fly). The Woody arms are generally acknowledged to be very fine sounding.

The Woody string bearing occupies a space that is about .12 inches tall by about .06 inches wide. The bearing is located just above the armwand, and supported from a vertical axis knob at the center of a platform above the armwand. The knob allows a twist to be put into the bearing to create anti-skate (which can be adjusted on the fly). The bearing consists of four strings (of very high strength, comparable to Kevlar) forming an inverted pyramid above the pivot point and an upright pyramid below the pivot point. The inverted pyramid is attached to the anti-skate knob. The upright pyramid is attached to the top of the armwand. The pivot is the point where the apex of the upper pyramid touches the apex of the lower pyramid.