It is rigidly mounted on helix shaft. Pointer stops of molded rubber prevent pointer over-travel without damage. Samarium cobalt magnet mounted at end of range spring rotates helix without mechanical linkages. Sapphire bearings for helix are shock- resistant mounted. They provide virtually friction-free rotation for helix.
Rotation is damped with high viscosity silicone fluid.
Helix is precision milled from an alloy of high magnetic permeability, deburred and annealed in a hydrogen atmosphere for best magnetic qualities. Mounted in sapphire bearings, helix rotates to align with magnetic field of magnet and transmit pressure indication to pointer. Zero adjustment screw is conveniently located in plastic cover, accessible without removing cover. Range spring calibration is screw adjusted. Rate adjust and rate adjust lock are coaxial and are factory set and sealed.