Heritage 1854› Movement Library› Model 81
Service Manual · Heritage 1854

The
Model 81

9¾ Ligne Calendar · Model 80 Base

A calendar movement built on the Model 80. The entire calendar mechanism is housed between the date frame assembly and the dial, so it lifts off as a stack without disturbing the movement underneath.

Hand-wound Calendar V-Conic Model 80 Base
The Model 81 movement, dial side and movement side
Factory Service Manual · Model 81 · Dial Side & Movement Side
Technical Specifications
Ligne9¾
BearingsV-Conic
ConstructionTwo plate, full plates
Basic movementModel 80
CalendarBetween date frame and dial
Dial fixingFour tabs through the date frame
ManualService Manual · Model 81
Size (mm)18 × 21.95 mm
Height4.90 mm
Jewels0
EscapementPin lever
Beat rate18,000 bph
Power reserve41 h
Size in mm, height, jewels, escapement, beat rate and power reserve: ranfft.org

A Calendar on the Model 80

The TIMEX Model 81 is a 9¾ ligne calendar movement which utilizes the basic Model 80 movement with the “V-conic” bearing system and rugged two plate design. The entire calendar mechanism is housed between the date frame assembly and the dial.

Note: The movement underneath is the Model 80, and this manual does not repeat its servicing. For the base movement, its cleaning and its lubrication, see the Model 80 guide.

Exploded View

Model 81 movement, exploded view
Model 81 · 35 Components
Ref.Component
100Dial Plate Assembly
118Movement Plate Assembly
145/2Date Frame Assembly
180/1Barrel Assembly
201/12nd Wheel Assembly
2103rd Wheel Assembly
2274th Wheel Assembly
242Cannon Pinion Assembly
255Hour Wheel Assembly
260Minute Wheel Assembly
401/1Crown & Stem Assembly
416Ratchet Wheel
423/1Rocking Bar Bushing
437Rocking Bar Assembly
439Rocking Bar Spring
443Set Lever
450Intermediate Wind Pinion
450/1Winding Stem Pinion
452Wind & Set Pinion
495Ratchet Wheel Washer
495/2Winding Bridge
498/1Hour Wheel Washer
705Escape Wheel Assembly
710Pallet Lever Assembly
721Balance Wheel Assembly
740Hairspring Wedge Pin
751Dial
850Hour Hand
851Minute Hand
852/1Sweep Second Hand
2556Date Wheel Assembly
2557/1Date Ring
2576Detent Spring
5118Pillar Screw
5443Set Lever Screw

Disassembly for Cleaning

Getting the movement out of its case first? Case types and dust seals

Removing the Dial and Calendar

A

Remove the sweep second hand, the minute hand and the hour hand.

B

The dial assembly is clamped to the movement by means of four tabs which are inserted through slots in the date frame assembly into two holes in the dial plate, and then bent under the plate to secure the assembly. Bend the tabs slightly to free the dial from the movement.

C

Then lift off in order: dial, date ring, hour wheel washer, hour wheel assembly, date wheel assembly, date frame assembly, cannon pinion assembly.

The Model 81 calendar stack lifted off the Model 80 movement
Fig. 81.3 · Calendar Stack

The Dial Tabs

•

Cross section showing a dial tab passing through the date frame assembly slot and the dial plate tab hole, bent under the movement plate.

Cross section of the dial tab through the date frame and dial plate
Fig. 81.3 · Dial Tab

Reassembly

Lubricant change, June 1974: Timex Service Bulletin No. 111 replaced the factory oil for this model. Moebius Synt-A-Lube oil is used instead of Elgin M56B oil or Tenneco #415 oil. (It supersedes Bulletin No. 108.)

Assemble the detent spring, if loose, into the date frame assembly. Place the date frame assembly on the Model 80 movement, being sure the date frame bosses are located in the two holes in the dial plate. Then assemble in order: date wheel assembly, cannon pinion assembly, hour wheel assembly, hour wheel washer.

Lubricate the cannon pinion bearing area and the date wheel bearing area with fine watch oil, Elgin M56b in the factory. Position the date ring on the date frame assembly.

Lubricating the Date Ring

•

Lubricate the face of the date ring and the detent spring with fine watch oil, Elgin M56b in the factory, as shown.

Lubrication points on the face of the date ring and the detent spring
Fig. 81.4 · Date Ring & Detent Spring

Insert the dial tabs, which should be straight, through the slots in the date frame assembly. Hold the dial in position and bend the four tabs under the dial plate.

Hands & Date

To Position Hands for Proper Date Change

•

With the dial assembled to the movement, pull the crown and stem assembly into the set position and rotate the crown clockwise until the date starts to move. Continue to rotate slowly until the date jumps into place, then stop rotating. Replace all hands at the 12 o’clock position. Be certain the sweep second hand is set below the chamfer on the top of the staff.

Cross section showing the sweep second hand set below the chamfer
Fig. 81.4 · Setting the Hands

Test the assembly for proper function of the hands and calendar mechanism.

To Set the Date

Pull the crown out to the set position and rotate the hands forward clockwise until the date shown in the window changes. The date may now be advanced rapidly by first rotating the hands backwards past 9 o’clock and then rotating them forward past 12 o’clock. The date will advance each time the backward and forward cycle is repeated.

Setting the time correctly: The date may also be advanced by rotating the hands forward through 24 hours. After the correct date is set, and remembering that the date change occurred at the equivalent of 12 o’clock midnight, set the time properly for AM or PM. Otherwise the next date change will occur during mid-day instead of at midnight.