AS 1803 (ST)

AS 1803 (ST) | - The Movement Archive

AS 1803 (ST)


The 11 1/2 ligne AS 1803 was released as so-called “Standard” caliber around 1970. It should be a cost-efficient but good quality alternative to check Roskopf movements, which especially on upcoming quartz crisis were a threat to the manufacturers under the roof of the Ebauches SA.

It bases on the caliber AS 1800 and extends it with a date indication and a semi-fast corrector.

AS 1803 (ST): base plate

base plate

Of course, all bearings contain rubies, even that of the center seconds pinion.

AS 1803 (ST): gear train

gear train

The AS 1803 (ST) already uses a modern gear train without a center minute wheel.

The mainspring barrel drives the second wheel (at 9 o’clock), which on the dial side only drives the hands. On the movement side, third wheel, directly driven center seconds wheel and escape wheel finish the gear train.

AS 1803 (ST): side view of the gear train

side view of the gear train

The two leg anular balance beats with 18000 A/h and is secured in two Incabloc shock protections. It regulates a swiss pallet lever escapement and can be adjusted on the hairspring key only.

AS 1803 (ST): empty dial side

empty dial side

On the yet empty dial side, you can see at position 3 o’clock half way to the center, the axle of the third wheel.

AS 1803 (ST): time display mechanism

time display mechanism

On this axle, mounted with a slipping clutch, there’s the wheel, which drives the hands, or to be precise, the changer wheel, which drives cannon pinion and hour pinion simulaneously. On the other side, this wheel engages with the keyless works (on the picture, the breguet clutch is missing).

AS 1803 (ST): calendar mechanism

calendar mechanism

The calendar mechanism uses an elaborate switching wheel (at 8 o’clock), whose switching finger is mounted moveable, so that it can realize a semi-fast calendar correction by turning the hands back an forth between 8 and 12pm.

A bit less elaborate is the lever at 11 o’clock, which locks the date ring, because its supporting spring loves to fly.

AS 1803 (ST): AS 1803 (ST): Dial side

AS 1803 (ST): Dial side

When the calendar mechanism is covered, the dial side of the AS 1803 makes a very robust appearance.

A nice detail on AS movement is the date font, which is, at least compared to ETA movements, more massive and so gives a hint, which movement (manufacturer) is used in a watch, even when you don’t yet see the movement.

Technical data

Caliber:1803 (ST)
Caliber base:AS 1800
Size:11 1/2''' (measured: 25,6mm)
lift angle:52°
Number of jewels:17
Escapement:Pallet lever
Balance types: monometallic anular balance (two legs)
Shock protection(s): Incabloc
Balance bearing / direction hairspring:Clockwise
Moveable stud:yes
Adjust mechanism:Hairspring key
  • lever
  • escape wheel, seconds wheel, third wheel, large driving wheel
  • mainspring barrel
Construction type:solid construction
Winding mechanism:yoke winding system
Setting lever spring:1 hole(s)
  • SCD (direct center seconds)
  • QG (date indication (aperture))
  • RDR (date corrector)
References: Flume: K3 36
Inventory number:22032

Usage gallery

AS 1803 (ST): Cauny skin diver

Cauny skin diver

AS 1803 (ST): Vulcaim gents watch

Vulcaim gents watch

These movements and watches are a kind donation from Chris to the movement archive. Thank you very much for your great support!