Watch with chaff-cutter escapement by John Grant

Made:
1804 in London
Watch with chaff-cutter escapement by John Grant (watch; lever movement) Watch by John Grant, London, 1804-5

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Science Museum Group / The Clockmakers' Museum
© The Board of Trustees of the Science Museumum

Watch by John Grant, London, 1804-5
Science Museum Group / The Clockmakers' Museum
© The Board of Trustees of the Science Museum

Watch by John Grant, London, 1804-5. Gold case, hallmarked for London and stamped with the makers mark 'IF'. White enamel dial with eccentric hour circle and subsidiary seconds. Gold hands. Signed 'Grant, Fleet Street, London, No. 2802'. Dust cap, signed 'Grant, Fleet Street, London, 2802.' Movement with escapement generally referred to as 'Grant’s chaff-cutter' escapement. In this form, the escape-wheel is at right angles to the plates and driven by a contrate wheel. The lever has its pallets in two planes, working across the plane of the escape wheel. The ‘fork’ of the escapement is in the form of a loop encircling the balance staff, impulse and locking taking place on the far side of the escape wheel. The two-armed compensation balance has sliding weights and a helical balance spring with no curves. There is no draw on the escapement. Signed on the movement 'Grant Fleet Street London 2802'. Presented to the Museum of the Worshipful Company of Clockmakers by John Grant (Junior) in 1874. Clockmakers' Museum No. 461

Details

Category:
Clockmakers
Collection:
The Worshipful Company of Clockmakers
Object Number:
L2015-3371
Materials:
gold (metal), brass (copper, zinc alloy), steel (metal), enamel, glass and diamond
Measurements:
overall: 78 mm x 62 mm x 26 mm,
type:
watch and lever movement
credit:
Lent by the Worshipful Company of Clockmakers