Seiko Base Metal and Stainless Steel Watch Case Back
Watch component (Case Back and Lugs) · N/A - This is a silver-toned base metal alloy and stainless steel component, not a gold item.
Purity: Non-gold; 0% purity. The item is composed of Base Metal and Stainless Steel as indicated by the stamps.
Type
Watch component (Case Back and Lugs)
Purity
Non-gold; 0% purity. The item is composed of Base Metal and Stainless Steel as indicated by the stamps.
Gold Type
N/A - This is a silver-toned base metal alloy and stainless steel component, not a gold item.
Weight
5-10 grams (total estimated weight of the case back and attached frame)
Description
This is a vintage Seiko watch case back and housing. The central disc is made of stainless steel for corrosion resistance against skin oils, while the outer housing is made of 'Base Metal,' typically a brass or nickel alloy that was originally plated (though the plating appears heavily worn or polished off). It represents a standard quartz-era dress watch component.
Key Features
Features the 2H20 movement reference, which is a slim, high-quality Japanese quartz movement often used in ladies' dress watches. The serial number 113885 provides specific production batch data.
Color & Finish
Silver-toned metallic color with a brushed/satin finish on the case back and a high-polish finish on the surrounding lugs/case frame.
Hallmarks & Stamps
SEIKO, BASE METAL, ST. STEEL BACK, 2H20-5630 RO, JAPAN MS, and a serial number '113885'. Marks indicate the manufacturer, material composition, movement-case reference, and production origin.
Dimensions Estimate
Approximately 25mm to 30mm diameter for the case back; lugs sized for a narrow strap (likely 12mm-14mm).
Gemstones & Inlays
None present.
Clasp & Closure
Snap-on pressure-fit case back design for sealing the watch movement.
Chain & Links
N/A - This is a watch case; it features integrated lugs for a strap or bracelet attachment.
Craftsmanship Details
Industrial mass production. The case back is stamped stainless steel, while the frame is a cast or machined base metal alloy. Functional and durable for its intended purpose but lacks luxury hand-finishing.
Authentication Indicators
The 'Base Metal' and 'St. Steel Back' stamps are classic 'red flags' for gold hunters—they explicitly state the item is not gold. The crispness of the Seiko stamping and the movement code format are consistent with genuine Seiko production.
Origin & Maker
Japan; manufactured by Seiko, a world-renowned horological brand established in 1881.
Era & Period
Late 20th Century (likely 1980s or 1990s based on the movement reference 2H20 and font styles).
Age Estimate
Circa 1991 (based on the first digit of the serial number '1' and the period of the 2H20 movement).
Cultural Significance
Represents the 'Quartz Revolution' era where Seiko became a global leader by producing affordable, reliable timepieces for the mass market.
Condition Notes
Fair to Poor. Significant surface scratching ('desk diving' marks), pitting on the base metal lugs, and wear to the original finish/plating. The metal shows signs of heavy use.
Value Estimate
Minimal monetary value; primarily value as a parts donor for a Seiko 2H20-5630 restoration. Melt value is $0 as there is no precious metal content.
Care & Maintenance
Clean with a soft microfiber cloth; avoid water exposure as the gaskets in a case of this age are likely degraded and no longer provide water resistance.
Similar Items
Often confused with 'Gold Filled' or 'Gold Plated' watches. Unlike those, this piece lacks any gold content markings and is strictly utility-grade materials.
Interesting Facts
In the vintage watch market, the term 'Base Metal' usually refers to an alloy of copper, zinc, and nickel. These were often gold-plated, but when the plating wears off, only the duller grey or yellowish base metal remains.