Heritage 1854› Movement Library› Model 27
Service Manual · Heritage 1854

The
Model 27

Day & Date · 13 Ligne

A 13 ligne day and date movement. It is the same as the Model 24 with a day and date mechanism added, so once the day frame assembly is off, the servicing is Model 24 servicing.

Hand-wound Day & Date 13 Ligne Model 24 Base
The Model 27 movement, dial side and movement side
Factory Service Manual · Model 27 · Dial Side & Movement Side
Technical Specifications
Ligne13
Diameter28.96 mm
Diameter (inches)1.140 in
TypeHand-wound day & date
Built onModel 24 movement
SettingDay and date set manually
ManualService Manual · Model 27
Height5.50 mm
Jewels0
EscapementPin lever
Beat rate18,000 bph
Power reserve42 h
Height, jewels, escapement, beat rate and power reserve: ranfft.org

A Model 24 with a Calendar

The Timex Model 27 is a 13 ligne day and date movement. The Model 27 movement is the same as the Model 24 movement except that a day and date mechanism has been added. When the day frame assembly has been removed, basic servicing techniques are the same as for the Model 24. The day and date can be set manually.

Note: Because the Model 27 is a Model 24 underneath, the disassembly, cleaning and reassembly of the base movement are covered in the Model 24 guide. This page covers what the Model 27 adds.
Timex Model 27, movement
Photo courtesy of ranfft.org

Exploded View

For the movement underneath, see the Model 24 exploded view.

Model 27 movement, exploded view
Model 27 · Day & Date Parts
Ref.Component
145Dial Rest
242Cannon Pinion Assembly
255Hour Wheel
498/1Hour Wheel Washer
751Dial
850Hour Hand
851Minute Hand
852/1Sweep Second Hand
2557/1Date Ring
2561/1Day Frame Assembly
2573Day Detent Spring
2575Date Lever
2576Detent Spring
5145Pillar Screw

How the Indexing Works

Date Ring Indexing

a

A finger integral with the date wheel on the underside engages and moves the date lever backward one tooth of the date ring.

b

At a pre-determined time the date lever is released, carrying the date ring forward one tooth.

c

A detent spring serves to prevent the date ring from backing up under shock, or when the date lever is being moved.

Model 27 day and date dial, showing the date ring and day ring
Fig. 27.3 · Date Ring Indexing

The Date Lever and Detent Spring

•

The date lever, detent spring and date ring seen from the dial side.

Detail of the date lever, detent spring and date ring
Fig. 27.3 · Date Lever & Detent Spring

Day Ring Indexing

a

A finger integral with the date wheel on the top side engages the day pinion and moves the day ring.

b

A detent spring holds the day ring in position and also aids in moving the day ring.

Model 27 day ring and day pinion
Fig. 27.3 · Day Ring Indexing

The Day Pinion and Date Wheel Finger

•

The date wheel finger engaging the day pinion. Use the exploded view as a guide in disassembly and assembly of the mechanism.

Detail of the date wheel finger and day pinion
Fig. 27.3 · Day Pinion

Cleaning & Lubrication

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.)

All cleaning and lubricating points indicated for the Model 24 should be followed for the Model 27. In addition to the Model 24 lubricating points, the underside of the dial rest, the underside of the day frame assembly and the date ring require lubrication. The dial rest and the day frame assembly are lubricated while apart from the movement; the date ring must be lubricated when the mechanism is reassembled. The preferred oil is Elgin M56B, with Hamilton PML grease preferred for the date ring and day frame detent spring.

Caution: Remember that the day and date ring actually are printed dials, and some watch cleaning fluids will strip the printing.

Oil Points on the Movement

•

The oil points the calendar adds, marked on the movement side. Both sides where indicated.

Model 27 oil points on the movement
Fig. 27.4 · Oil Points

The Day Frame Detent Spring

•

Grease at the junction of the day detent spring and the day pinion, applied while the day frame assembly is apart from the movement.

Grease point on the day frame assembly and day detent spring
Fig. 27.4 · Day Frame Assembly

The Date Ring

•

Grease on the date ring, applied when the mechanism is reassembled.

Warning: Never lubricate the junction of the day pinion with the day frame, for this may cause a failure.
Grease points on the date ring
Fig. 27.4 · Date Ring

Positioning the Hands

To Position Hands for Proper Day and Date Change

1

Hold the watch assembly movement side up with the crown and stem at the three o’clock position. Pull out the crown and stem.

2

Rotate the crown and stem slowly and observe the date lever at the nine o’clock position. The date lever will then begin to move and a click will be heard.

3

After the click, rotate the crown slowly until the date lever snaps back. At this time stop rotating.

4

Finally, replace all hands at the 12 o’clock position.

The date lever at the nine o’clock position on the movement
Fig. 27.5 · Date Lever Position