A replica wallingford clock

摘要

To get the correct tooth shapes on the spiral contrate gear, cuts at several settings had to be made before the final form was reached. After all was satisfactory the flange was turned off and the finished gear is shown in photo 30. The mating wheel is a simple 12-tooth spur gear. The next part of the train consists of straightforward gears, pinions, a contrate, a few worms and worm wheels. Some of the worms were two-start and as the arbors of the mating wheels are not at right angles the teeth of these wheels had to be cut at odd angles. To be correct they should have been spiral cut but the early craftsman had to straight cut them with chisel and file so I straight cut them as well.