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![]() Grasshopper escapement Pallets positioned by spiral springs, just visible. Escape wheel 5 spokes, 1 rev. in 5 mins. 100 pins, 0.6mm ∅ Escape wheel rim 5mm cross-grain balsa sandwiched between two layers of 1 mm ply. Pinion six 3mm ∅ pins each with a 4 mm brass sleeve. Sleeves are free to rotate. Hour-wheel with 72 teeth each 5 x 5 x 17 mm, sanded to involute curve. and sandwiched between two layers of 1 mm ply. Hubs 12 x 1 mm brass tube two 10mm ball-bearings on 5 mm steel axles. Hour hand is turned by a daisy wheel. Pendulum varnished spruce. Pendulum weight: steel tube, 35cm long 4.5cm outside diam. |
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VariationsWhen this clock was shown at the University of Tokyo in 2007 it ran very slow so I had to raise the weight of the pendulum by about 5mm. I believe this was because of the reduced gravity in Tokyo (35.6°N) compared to Berlin (52,5°N).According to the World Gravity Network map, Potsdam: 981.274 Gals, Kyoto: 979.72 Gals. ← I also showed it in a exhibition in Burg Eisenhardt, a castle in the Mark Brandenburg, which has high ceilings. I took the opportunity of making a two second pendulum - about four metres long. (Since it ticked slower I had to make a new escape wheel: with 75 pins instead of 100.) |