- Museum number
GOLD-PLATED BRASS CASED PIN-PALLET LEVER WATCH.
Ingersoll Junior pocket watch.
Movement with steel plates and pin-pallet lever escapement; keyless winding and hand setting.
White paper dial with Roman numerals and subsidiary seconds.
Blued steel hands.
Brass case with snap-on back and bezel.
- Production date
Diameter: 46.50 millimetres (case)
Diameter: 37 millimetres (dial)
Thickness: 13.80 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Ingersoll movement type 7A
A paper dial with metal backing fixed to the plate by tags.
Frame: A full plate layout with a bridge for the balance. The plates of nickel silver. The barrel bridge is screwed to the back plate with two screws. The back plate is supported by three brass cylindrical pillars and the keyless block and secured by screws.
There is a bridge for the third and fourth wheels rivetted to the front plate beneath the dial.
Barrel and Mainspring:
Going barrel internal diameter 16.0 mm., height 2.5 mm.
Mainspring: height 2.45 mm., thickness 0.19 mm.
Arbor: diameter 4.6 mm., not snailed.
Hooking: Pressed in from the barrel wall.
Train: All brass wheels, with three crossings for the escape and four crossings for the centre, third and fourth wheels.
Jewelling: No jewels, the balance staff has cone ends running in steel cups, that in the front plate can be adjusted for correcting the endshake.
Escapement: A pin pallet lever escapement, straight line layout, long lever, effectively a double roller, with the round steel impulse pin set in the balance arm and a small roller of steel. Brass lever, steel pallet pins. An equal impulse escapement.
The escape wheel brass.
No. of teeth embraced 3 ½.
Balance: A single arm monometallic balance with a plain rounded rim. The balance diameter 12.15 mm., thickness 0.55 mm. A blued-steel flat spiral spring with approximately 13 turns pinned into a stud bent down from the balance bridge.
Means of Regulation: Blued-steel index on the back plate registering against a stamped divided scale with 'F S'.
Train Counts and Beat Rate:
Great wheel (barrel) 66
Centre wheel 64 pinion 8
Third wheel 60 pinion 8
Fourth wheel 63 pinion 8
Escape wheel 15 pinion 7
Beat rate 14,400
Motion work: cannon pinion 8 (pressed onto the centre arbor which can slip in the wheel and pinion assembly)
Minute wheel: 24, minute pinion 8
hour wheel 32
Winding system: Stem set rocking bar keyless winding. The barrel ratchet wheel is held down by a steel cock.
Dimensions: Movement diameter 39.7 mm., height 9 mm.
Note: The latest patent recorded on this type is 1925. For full details see registration nos1983,1012.74 - 80 and 1983,1210.122.
- Not on display
- Latest: 4 (2017) verdigris
- Acquisition date
- Britain, Europe and Prehistory
- Registration number