Keystone Watch Co. Patent "Dust Proof" Pocket Watch, c. 1887
Record status
Individual type · partial
Period
c. 1887
According to the Pocket Watch Database blog, this pocket watch dates to circa 1887 and was manufactured by the Keystone Watch Co. The movement is an 18-size design featuring gilt-damaskeened plates and 10 jewels.
Its distinctive feature is a patented dust-proof windowed attachment covering the balance wheel, intended to seal the internal mechanism from outside debris. The watch incorporates Abraham Bitner's patent micrometric regulator alongside other patents granted during Bitner's tenure. Source documentation records that the movement is cased in a gold-filled Essex Watch Case Company case under the Standard trademark.
Evidence at a glance
- Linked sources
- 1
- Photograph views
- 1
- Catalogue references
- 0
Counts describe this entry’s documentation, not authenticity, rarity or completeness. Photographs may show one specimen; check each caption and licence.
Technical characteristics
- Type
- Dust-proof pocket watch
- Place recorded
- United States
- Case Manufacture
- Essex Watch Case Company gold-filled case
- Regulator Patent
- Abraham Bitner's Patent Micrometric Regulator
- Maker / attribution
- Keystone Watch Co.
- Dust Proof Mechanism
- Windowed attachment covering the balance wheel
- Movement Size and Configuration
- 18-Size, Gilt-Damaskeened Plates, 10 Jewels
Design
- Visible features
- • Curved transparent window covering the balance opening adjacent to the balance cock • Gilt-damaskeened movement plate engraved with 'PAT. DUST PROOF.' and partial serial digits '570' • Steel micrometric regulator index arm positioned over a graduated scale • Threaded fine-adjustment screw mechanism and tension spring fitted to the regulator arm • Blued steel screws securing regulator components on the balance cock • Hinged metallic case rim visible along the left margin
- Reported Casing, Hands, and Source Scope
- The source documents that the complete watch was fitted with '“Keystone” shape gilt hands' and housed in a gold-filled case manufactured by the Essex Watch Case Company, marked under the '“Standard” name and trademark'. Furthermore, the source notes historical retail through the 'Atkinson Bros. company' in the late 1880s via watch clubs. However, physical verification from the provided primary detail image is limited strictly to the balance cock, regulator, transparent window, and adjoining plate edge. The full dial layout, the complete serial number, the remainder of the movement, and the exterior of the Essex case are not depicted in this image and remain unverified by direct visual inspection.
- Reported Movement and Patent Specifications
- According to the source documentation, the movement is an 18-size, 10-jewel mechanism featuring gilt-damaskeened plates, assigned an estimated total production run noted as 'ETP ~7,400'. The dust-proof function relies on a 'windowed attachment covering the balance wheel – essentially “sealing” the mechanics of the watch from outside debris'. The watch mechanism incorporates 'Abraham Bitner’s Patent Micrometric Regulator' along with several other patents granted to Bitner during his period of leadership at the Keystone factory. The movement is dated approximately to circa 1887 in the source title.
- Visible Balance Cock and Dust Proof Construction
- Macro examination of the movement reveals a specialized curved transparent window secured over the balance wheel opening adjacent to the balance cock. This construction corresponds directly to the patented design feature intended to enclose the balance assembly. The adjacent movement plate displays gilt damaskeening and is engraved with the designation 'PAT. DUST PROOF.' alongside visible partial serial digits '570'. A steel micrometric regulator index arm extends over an engraved graduated scale, controlled by a threaded fine-adjustment screw mechanism, tension spring, and blued steel fastening screws. Along the outer margin, a hinged metallic case rim is visible.
Identification
- Source note
- Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.
Catalogue references
No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.
Research required
- Research required: Full dial, entire movement layout, and case exterior are not depicted in this macro detail view
- Research required: Only trailing digits of the serial number are visible on the plate edge