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The Encyclopedia of Horology

Wristwatch · Manual-wind wristwatch

Gruen Precision Wristwatch, Caliber N510SS

Partially verified

This is a vintage Gruen Precision manual-wind wristwatch reported by the seller to date from the 1960s. The piece features a gold-tone base metal bezel with a stainless steel back, measuring 33.2 mm in diameter. Its silver sunburst dial is fitted with applied gold-tone Arabic numerals at 12 and 6, baton hour markers, luminous dots, and luminous hands. The source reports that the watch is powered by a 17-jewel Swiss Gruen caliber N510SS manual movement operating at 18,000 beats per hour with a sweep second hand.

Front view of the Gruen Precision wristwatch dial, gold-tone bezel, and brown strap
Front view of the Gruen Precision wristwatch dial, gold-tone bezel, and brown strap — SECOND HAND HOROLOGY. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
secondhandhorology.com
Category
Wristwatch · Manual-wind wristwatch
Maker / attribution
Gruen Watch Co.
Reference
510 RSS
Catalogue / lot identifier
WA-3361
Source-reported date
1960s
Country
Switzerland

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Dial and Visual Presentation

The watch features a silver sunburst dial configured with applied gold-tone Arabic numerals at the 12 and 6 positions alongside baton indexes. Luminous dots accompany the hour markers, paired with matching gold-tone luminous hour and minute hands and a central sweep second hand.

Visual markings reported on the dial include the Gruen name, 'Precision', 'Waterproof', and 'Swiss'. The watch is fitted with an aftermarket two-piece brown leather strap with a gold-tone buckle.

Evidence for this section
  • “original silver sunburst dial with gold Arabic numerals and baton hour markers, luminous dots and luminous gold matching hands”
  • “The dial is signed with the Gruen name, Precision, Waterproof, and Swiss.”
  • “It comes on a beautiful new, brown, two-piece leather strap with a gold buckle.”

Case Construction and Dimensions

The round case measures 33.2 mm in diameter (35 mm including the crown), with a lug-to-lug distance of 41.8 mm and a thickness of 9.2 mm. Lug width is listed as 17.7 mm, tapering to a 16.5 mm band width.

The listing notes a base metal bezel paired with a stainless steel back. Reported case-back markings include 'Gruen Precision Waterproof Shock Resistant Anti-Magnetic Base Metal Bezel Stainless Steel Back Stainless Steel Back Gruen Watch Co. 510 RSS'.

Evidence for this section
  • “Case diameter: 33.2 Case with Crown: 35 Case Lug to Lug: 41.8 Case Thickness: 9.2 Lug Width: 17.7 Band Width: 16.5”
  • “Case Back Signed: Gruen Precision Waterproof Shock Resistant Anti-Magnetic Base Metal Bezel Stainless Steel Back Stainless Steel Back Gruen Watch Co. 510 RSS”

Movement Specifications and Cataloguing Constraints

The internal movement is not visible in the provided primary photograph; its details rely entirely on the seller's transcription. The movement is reported as an unadjusted Swiss-made Gruen manual-wind caliber N510SS with 17 jewels, operating at a frequency of 18,000 beats per hour (2.5 Hz) with a stated 42-hour power reserve.

The seller dates the piece to the 1960s, though no serial number or factory ledger documentation is provided in the source to verify this date. Additionally, historical dial designations such as 'Waterproof' reflect original period trade labeling and are not verifiable indicators of modern water resistance.

Evidence for this section
  • “original Gruen Precision movement caliber N510SS with 17 jewels, a frequency of 18,000 beats per hour (2.5 Hz), a 42-hour power reserve, sweep second hand, unadjusted, and is Swiss made”
  • “Movement: Gruen Watch Co. Swiss Seventeen 17 Jewels N 510 SS”
  • “vintage Gruen Precision wristwatch dated from the 1960s”

Open research questions

  • Does Gruen caliber N510SS correspond to an ebauche base from an external maker (such as A. Schild) or an in-house Gruen caliber?
  • Can reference 510 RSS be cross-referenced with Gruen dealer catalogs or reference guides to confirm the precise manufacturing window within or beyond the 1960s?
  • What specific luminous material was applied to the dial dots and hands on this model during its period of production?

Source evidence

Recorded claims and source quotations for Gruen Precision Wristwatch, Caliber N510SS
FieldSource-reported valueSource quotation
Movement CaliberN510SS“original Gruen Precision movement caliber N510SS with 17 jewels”
Frequency18,000 beats per hour (2.5 Hz)“frequency of 18,000 beats per hour (2.5 Hz)”
Case Diameter33.2 mm“Case diameter: 33.2”
Case Back Reference Marking510 RSS“Gruen Watch Co. 510 RSS”
OriginSwiss made“and is Swiss made”
Reported Power Reserve42 hours“a 42-hour power reserve”
Case Length Lug-to-Lug41.8 mm“Case Lug to Lug: 41.8”
Case Thickness9.2 mm“Case Thickness: 9.2”
Lug Width17.7 mm“Lug Width: 17.7”

Visible details

  • Gold-tone round case with prominent lugs and a fluted crown at 3 o'clock.
  • Silvered dial signed 'GRUEN PRECISION' below 12 and 'WATERPROOF' above 6.
  • Applied gold-tone Arabic numerals at 12 and 6 alongside baton hour markers.
  • Gold-tone luminous hour and minute hands with a sweep second hand.
  • Mounted on a dark brown textured leather strap.

Research qualifications

  • The internal movement and case back markings are not directly visible in the primary photograph.
  • Historical waterproof markings should not be relied upon for current water exposure.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Vintage GRUEN Precision Wristwatch 17 Jewels Swiss Caliber N510SS Watc – SECOND HAND HOROLOGY

Reviewed 2026-10-21 · Record 6fd73dc123

Terms in this record

Glossary explanations for terms named in this object’s record.

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