Pierce 861 SC

Pierce 861 SC | 17jewels.info - The Movement Archive

Pierce 861 SC


A rare representative when it comes to wristwatch movements is Pierce, formerly also known under the brand name “Eclipse”. Pierce is mainly known for its unusual designed chronograph movements and early automatic movements with rattle winding.

The Pierce 861 SC however, is a true windup movement with a center seconds indication and because of its size of only 8 3/4 lignes (19,3mm), it was suitable for smaller ladies' watches.

Pierce 861 SC: base plate

base plate

For the time being, the jewel count of 17 is unusually high and results of a double ruby-beared minute wheel. Besides that, the execution is the usual fair quality standard of the 1940s and 1950s.

Pierce 861 SC: gear train

gear train

The gear train uses compareatively large wheels. For space reasons, the escape wheel runs partially open on the dial side (the slanted rim of the dial side requires the opening).

Construction wise, it follows the usual standard with mainspring barrel, directly driven center minute wheel, thrird wheel, seconds wheel at 6 o’clock and escape wheel.

A second wheel on the third wheel pin drives the indirect center seconds pinion, which is located on top of the gear train bridge and fixed by a flat spring.

Pierce 861 SC: side view of the gear train

side view of the gear train

The swiss pallet lever escapement is controlled by a two-leg screw balance, which is already beared in two Incabloc shock protections.

The beating rate of 18000 A/h can be adjusted with the help of a long regulator arm.

Pierce 861 SC: w/o center seconds

w/o center seconds

The Pierce 861 SC uses a separate escape wheel cock. On its top, the flat spring for the center seconds pinion is fixed.

All visible bearings on the dial side have got a golden toned edging to give the impression of chatons, but in fact, they are only normal jewels.

Pierce 861 SC: Pierce 861 SC: Dial side

Pierce 861 SC: Dial side

The golden toned edging is not used on the dial side.

There, the yoke winding system, the Incabloc bearing and the slanting of the edges can be seen, as well, as the two screws for securing the dial feet.

Technical data

Caliber:861 SC
Caliber base:Pierce 861
Size:8 3/4''' (measured: 19,3mm)
Number of jewels:17
Escapement:Pallet lever
Balance types: monometallic screw balance (two legs)
Shock protection(s): Incabloc
Balance bearing / direction hairspring:Clockwise
Moveable stud:no
Adjust mechanism:Long regulator arm
  • lever
  • escape wheel
  • seconds wheel, third wheel, center minute wheel
  • mainspring barrel
Construction type:solid construction
Winding mechanism:yoke winding system
Attachment of setting lever:screwed
Setting lever spring:2 hole(s)
  • SCI (indirect center seconds)
References: Ebauches: Tome 2, 118
Feilner: Bl.22 888
Flume: K1 19
Inventory number:23013

Usage gallery

Pierce 861 SC: Pierce ladies' watch  (case missing)

Pierce ladies' watch (case missing)