Rolex - Oyster Speedking Precision - 6420 - Unisex - 1957

Rolex Oyster Speedking Precision 6420 – 30 mm – manual wind – caliber 1210 – silvery dial – 1957

A classic vintage Rolex Oyster Speedking Precision, reference 6420, implemented in a compact 30 mm stainless steel Oyster case. This example dates from 1957, with the inner case back bearing the date code “II.57.”

The silvery dial has a pronounced vintage look with applied Arabic numerals and drop-shaped hour markers, dauphine-like hands, and a blued central seconds hand. The watch is powered by a mechanical Rolex hand-winding movement.

The watch shows clear age and wear consistent with its age. The dial displays patina and local discolorations. Importantly, the plexiglass is cracked. The mounted brown leather strap and buckle are not original.

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Basic information

Brand: Rolex
Model: Oyster Speedking Precision
Reference: 6420
Year: 1957
Case back date code: II.57
Diameter: 30 mm, excluding crown
Case material: stainless steel
Movement: mechanical hand-wind
Caliber: Rolex 1210
Dial: silvery
Functions: hours, minutes and central seconds
Glass: plexiglass
Bracelet: brown leather strap, not original
Buckle: steel, not original

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Important details

The Oyster Speedking 6420 belongs to the compact vintage Oyster models from Rolex and was produced, among other years, during the 1950s.

This example has several features typical of the period:
30 mm Oyster case
Smooth polished bezel
Screw-down case back
Rolex-signed screw-down crown
Mechanical hand-winding movement
Central seconds
Silver/Off-white Precision dial
Blue-steeled central seconds hand

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Year of manufacture

Year: 1957

On the inside of the case back the marking reads:

II.57

This case marking dates the case back to the second quarter of 1957.

Additionally, the reference 6420 is clearly marked on the inside.

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Case

Diameter: 30 mm excluding crown
Material: stainless steel
Form: classic Oyster case
Bezel: smooth and polished
Case back: screw-down
Crown: Rolex-signed screw-down crown

The case has the characteristic compact proportions of a Speedking from the fifties. The polished surfaces show fine hairlines, scratches, and signs of age.

Inside the case back are among other markings:

MONTRES ROLEX S.A.
GENEVA
SWITZERLAND
PATENTED
STAINLESS STEEL
6420
II.57

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Dial

Color: silver / off-white
Indices: applied Arabic numerals combined with drop-shaped hour markers
Minute scale: black peripheral minute track
Hour and minute hands: dauphine/ lancet-shaped with light inlay
Seconds hand: central blued
At 12 o’clock the Rolex crown and the inscriptions read:

ROLEX
OYSTER SPEEDKING

At 6 o’clock:
PRECISION

The dial shows clear natural signs of aging. The surface bears patina, small spots, pinpoint discolorations, and other age-related irregularities that give the dial a clearly seasoned vintage character.
The applied indices and hands also show visible aging.

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Glass

The watch is fitted with a domed plexiglass.

The glass shows clear signs of use and age and is cracked. A prominent crack runs across a large portion of the glass. Additionally, at the edge around 5–6 o’clock there is damage.
Because of this, replacement of the plexiglass is recommended.

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Movement

Caliber: Rolex 1210
Type: mechanical hand-wind
Jewels: 17
Frequency: 18,000 A/h
Functions: hours, minutes and central seconds

The movement is wound by hand via the crown. It is a classic Rolex hand-winding caliber from this generation of Speedking models.
The movement is Rolex-signed including “MONTRES ROLEX S.A. GENEVA SWISS”.
There is no recent service history noted. For a vintage mechanical watch of this age, periodic technical maintenance is advised.

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Crown

The grooved crown bears the Rolex crown marking.
The crown and surrounding case area show wear appropriate for the age of the watch.

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Caseback

The watch has a screw-down stainless steel Oyster case back.
The exterior shows several fine scratches and hairlines. The interior bears the Rolex factory marks, reference 6420 and the important date code II.57.

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Bracelet

Bracelet: brown leather with crocodile pattern
Condition: used
Originality: not original
Clasp: simple steel pin/buckle clasp
Originality of clasp: not original

The strap shows signs of wear, including creasing, wear at the lugs, and wear around the holes. Especially at the lugs there is clear wear of the leather.
Current fit is around 19.5–20 cm, depending on which hole is used.
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Condition

Case: used vintage condition with hairlines, scratches and signs of age.
Bezel: light scratches and minor signs of wear.
Dial: clear patina, discolorations, small spots and other signs of age.
Hands and indices: visible aging and patina consistent with age.
Glass: clearly damaged; the plexiglass has a prominent crack and damage to the bottom edge.
Caseback: several fine scratches and hairlines.
Bracelet: not original and used, with clear wear and creasing.
Clasp: not original, with normal signs of use.

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Water resistance

The Oyster construction includes a screw-down case back and screw-down crown. Given the age of the watch and the damage to the plexiglass, water resistance cannot be guaranteed.
For any contact with water, a full service check and pressure test are necessary.

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Overall condition

A characterful Rolex Oyster Speedking Precision reference 6420 from 1957, with the compact 30 mm Oyster case, hand-wind caliber 1210 and a strongly aged silvery dial.
The watch presents itself clearly as a vintage piece and shows obvious marks of its age. In particular, the patina of the dial and the cracked plexiglass front are important points of attention. The brown leather strap and steel clasp are not original.
The date code II.57 on the inside of the case back is a nice and concrete detail that allows this piece to be dated to 1957.