Uploaded September 2020 | Updated September 2026, 2 weeks ago
Timing is affected by the verniers located on the rear of the clock at the upper and lower points where the pendulum balance springs are located and can affect the tension of those springs not unlike what Harrison did on H1 through H3. But this is where the similarity ends. John Harrison used temperature compensating gridirons on H1 and H2 and then a bimetallic strip on H3 to control the tensioning of the plain steel springs in line with temperature change. We have substituted springs made from Elinvar NiSpan-C; similar to the material used in better watch hairsprings. Elinvar maintains constant elasticity vs. temperature. This is as important to springs as Invar material is in keeping a pendulum rod a constant length vs. temperature. So once the verniers are set, there should be little fiddling with them to maintain reasonable time.
Timing is affected by the verniers located on the rear of the clock at the upper and lower points where the pendulum balance springs are located and can affect the tension of those springs not unlike what Harrison did on H1 through H3. But this is where the similarity ends. John Harrison used temperature compensating gridirons on H1 and H2 and then a bimetallic strip on H3 to control the tensioning of the plain steel springs in line with temperature change. We have substituted springs made from Elinvar NiSpan-C; similar to the material used in better watch hairsprings. Elinvar maintains constant elasticity vs. temperature. This is as important to springs as Invar material is in keeping a pendulum rod a constant length vs. temperature. So once the verniers are set, there should be little fiddling with them to maintain reasonable time.
