8638ST

Royal Oak II 8638 — 8638ST

1976–c. 1981

Steel with the blue T21 Tapisserie dial of the 5402.

1,456 sold: 423 (1976), 370 (1977), 291 (1978), 226 (1979), 129 (1980), 17 to 1990.

Steel 29 mm 8638ST No. 370 (1976, sold 1977) on bracelet 424: blue T21 Tapisserie dial with AP monogram at 12, hours and minutes only. · Photo: Audemars Piguet · Licence pending · Source: https://apchronicles.audemarspiguet.com/en/model/8638

Identifying details

Octagonal bezel
Eight-sided bezel around a round dial opening.
Integrated bracelet
Metal bracelet designed as one with the case.
AP monogram at 12 o’clock
Applied “AP” monogram below 12 o’clock, adopted for the 5402 from 1977 so the hour hand clears the logo.
Petite Tapisserie dial
Guilloché grid of small truncated pyramids (Stern’s “T21” pattern), the original Royal Oak dial.

Variants of 8638

Reference overview →

Switch between variants of this reference. The current variant is highlighted.
Variant	Production
8638STCurrent	1976–c. 1981
8638SA	1977–c. 1981
8638BA	1977–c. 1981
8638BC	1978–1979

Case & movement

Reference: 8638
Production: 1976–c. 1981
Case material: Stainless steel
Case diameter: 29 mm
Movement: Automatic
Date: No
Caliber: Audemars Piguet 2062

Dial, bezel & hands

Dial colour: Blue (Bleu Nuit, Nuage 50)

Unknown attributes are left out rather than guessed.

Movement

Audemars Piguet 2062

Small automatic (hours and minutes) on a Rayville ébauche (ref. 662) adapted with LeCoultre, which made the gold rotor. About 4,000 made 1976–1980, mostly for the ladies’ Royal Oak 8638.

Automatic · Introduced 1976 · 21,600 vph · 24 jewels · 38 h reserve · Ø 15 mm · 4.25 mm thick

Identifying details

Octagonal bezel

Eight-sided bezel around a round dial opening.

Integrated bracelet

Metal bracelet designed as one with the case.

AP monogram at 12 o’clock

Applied “AP” monogram below 12 o’clock, adopted for the 5402 from 1977 so the hour hand clears the logo.

Petite Tapisserie dial

Guilloché grid of small truncated pyramids (Stern’s “T21” pattern), the original Royal Oak dial.

Variant

Production

1976–c. 1981

1977–c. 1981

1977–c. 1981

1978–1979

Movement

Audemars Piguet 2062

Small automatic (hours and minutes) on a Rayville ébauche (ref. 662) adapted with LeCoultre, which made the gold rotor. About 4,000 made 1976–1980, mostly for the ladies’ Royal Oak 8638.

Automatic · Introduced 1976 · 21,600 vph · 24 jewels · 38 h reserve · Ø 15 mm · 4.25 mm thick

Royal Oak II 8638 — 8638ST

Identifying details

Variants of 8638

Case & movement

Dial, bezel & hands

Movement

Suggest a correction

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Royal Oak II 8638 — 8638ST

Identifying details

Variants of 8638

Case & movement

Dial, bezel & hands

Movement