Patek Philippe Calatrava 18K Yellow Gold Ref. 3445J 1960's

DETAILS
Manufacturer: Patek Philippe
Model: Calatrava
Reference Number: 3445J
Movement: Automatic
Condition: Very good (worn with little signs of wear)
Gender: Men’s/Unisex
Time Period: 1963
Retail / Compare-At Price: n/a collector’s item
Our Best Price: $16,950

CALIBER
Movement: -
Caliber: 27-460M
Jewels: 37

CASE
Case Material: 18K yellow gold
Case Diameter: 35 mm
Thickness: 10 mm
Waterproof: -
Water Resistance: -
Material Bezel: Fixed 18K yellow gold
Glass: Acrylic (apparent scratches on the glass that can be eliminated by polishing the crystal)
Dial: Champagne with radial brushing 
Dial Numerals: Yellow gold applied baton hour indices, outer perlé minute track around the outer rim

BRACELET / STRAP
Bracelet color: Blue
Bracelet Material: Leather
Clasp: Tang
Clasp material: Gold plated

FUNCTIONS
Hours, minutes, guichet date at three o’clock, subsidiary seconds dial at 6 o'clock

OTHERS
Yellow gold applied stick-shaped hour/minute hands small second hand
Solid two-body round case and bezel are polished/brushed, excellent condition
Solid 18K yellow gold screw-down case back
Sharp straight 18K yellow gold angled lugs with crisp and visible hallmark in the back
18k yellow gold pull/push recessed knurled crown with Calatrava cross engraved
The caliber 27-460 is stamped with the Geneva Quality hallmark, and it has the Patek Philippe seal. It's rhodium plated, with fausses cotes embellishment, a shock absorber device, and a straight-line lever escapement. It includes a self-adjustable balance spring stud carrier, an adjustable-mass balance with a Breguet over coil spring and a Gyromax balance that's adjusted for heat, cold, isochronism, and 5 positions, and a centrally mounted solid 18K yellow gold rotor, consummately decorated with engine turning.
This mechanism oscillates at the frequency of 19,800 vph (3 Hz). 
The caliber 27-460 M, successor of the caliber 12-600 AT, was the first automatic watch movement with a date produced by Patek Philippe in a series in production for 25 years, from 1960 to 1985.
This caliber 27-460M offers the same exquisite finishing as the 12-600 AT movement in the ref. 2526.
Walt Odets called Cal. 27-460 "the reigning queen of that half century" and "the most elaborate and costly simple automatic watch movement ever produced."
Caliber 27-460 M was also called "La Grande Dame des automatiques Suisse"
Incomplete (no box, with extract from the Patek Philippe Archives dated 1963)