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Explains the movement's construction, including full plates and V-Conic bearings for accuracy.
Provides an exploded view of the movement components with part numbers for identification.
Step-by-step guide for removing the sweep second hand, dial, and date ring.
Instructions for removing the date wheel and ratchet wheel assembly.
Procedure to detach the crown and stem assembly from the movement.
Detailed steps for safely removing the balance wheel assembly.
Outlines the methods for cleaning the movement using machines or manually.
Details specific points for oiling and the types of oils to use for lubrication.
Guide on correctly reinserting and adjusting the balance wheel assembly.
Instructions for reassembling the date wheel, date ring, and hands.
The TIMEX Model 25 is a calendar watch movement designed with a focus on accuracy, durability, and ease of maintenance. It incorporates a calendar mechanism, allowing the watch to display the date in addition to the time. The movement is built upon the basic construction of the Model 24, featuring a "V-Conic" Bearing system and a rugged two-plate design. This construction ensures that the entire calendar mechanism is efficiently housed between the dial plate and the dial itself.
Unlike many watches that rely on bridges, the TIMEX Model 25 utilizes full plates for its movement. This design choice is made to leverage the inherent accuracy associated with full-plate construction. This accuracy is crucial for ensuring complete interchangeability of components within the escapement and gear train. This means that parts can be replaced without the need for selective fitting or extensive adjustments, which often complicate the repair process for other watches. The emphasis on interchangeability simplifies repairs and reduces the time and specialized skills required for servicing.
The "V-Conic" bearing system is a key feature of the Model 25, used as bearings for the balance staff. This system contributes to the movement's overall accuracy and smooth operation. The bearing on the dial plate is mounted with a screw, allowing for fine endshake adjustment. This adjustability is important for optimizing the performance of the balance wheel, which is the heart of the watch's timekeeping mechanism.
For maintenance, the TIMEX Model 25 is designed for straightforward cleaning. To clean the movement, only a few key components need to be removed: the sweep second hand, dial, date ring, date wheel assembly, ratchet wheel, and balance. This minimal disassembly approach is based on extensive research by TIMEX, which found it to be the most effective method for cleaning. The cleaning process involves using cleaning fluid to remove contamination from the movement, which also removes oil from the gear train, pivots, and holes, necessitating re-oiling after cleaning. The balance assembly should be cleaned separately to prevent damage to the delicate hairspring. Standard watch cleaning solutions are recommended for this process.
If further dismantling is required beyond the basic cleaning procedure, removing the movement plate will expose the gear train and its associated parts. Re-assembly should begin with the dial plate, with careful attention to properly positioning pivots in their respective holes. An exploded view of the movement is provided in the manual to guide re-assembly, ensuring that all components are correctly placed.
Lubrication is a critical aspect of the Model 25's maintenance. After cleaning, the movement should be re-oiled using high-grade watch oils. The mainspring, however, is permanently lubricated with a solid coating that is not affected by normal cleaning solutions, so it does not require additional oiling. Specific points for lubrication include the upper pivot of the escape wheel (accessible through holes in the minute wheel), the "V-conic" bearings (to be oiled 1/2 to 3/4 full before replacing the balance wheel), both sides of the intermediate wind pinion and wind and set pinions, and the intersection of the rocking bar and set lever. A slot at the base of the center post facilitates oiling the fourth pinion upper pivot. If the friction pinion has been removed and cleaned, it should be oiled before re-assembly into the cannon pinion, and the impulse pin should be oiled at its working surface. For waterproof and dust-proof models, rubber gaskets on crowns should be lubricated with silicone grease or oil.
Re-assembly of the balance wheel requires careful handling. It should be inserted by tilting the wheel, placing the dial side pivot (hairspring side) first, and then the movement side pivot into the "V-conic bearing." The balance screw is then adjusted to hold the balance in place. The hairspring must be inserted into the regulator slot and hairspring wedge pin bracket by rotating the balance wheel. Before repinning the hairspring, it's essential to ensure the impulse pin is within the slot of the Pallet Lever fork. Repinning the hairspring requires precision to ensure the wedge pin is straight and true, as any distortion can interfere with the hairspring's normal "breathing." Endshake adjustment is performed cautiously, applying minimal downward pressure to the balance screw to avoid damaging the balance staff points. The hairspring's proper adjustment is critical; it should maintain light, permanent contact with the inside edge of the regulator slot throughout the balance's maximum oscillation.
The re-assembly of the date mechanism involves specific steps. The date wheel assembly is replaced on the movement with the large head of the bushing facing the dial. The date ring is then assembled, ensuring the "V" shaped end of the detent spring is positioned between two teeth of the date ring. The date wheel assembly is rotated clockwise until the indexing pin touches the exit side of a date ring tooth. The dial assembly is then positioned onto the movement with the hands set at approximately 2 o'clock. The lugs on the dial holder are bent to clamp the dial tightly to the movement, taking care not to alter the position of the hands, date ring, or date wheel assembly during this process. After the dial is clamped, the date indexing action can be checked. Indexing should start between 11 and 12 o'clock, and the date ring should exhibit a "snapping effect" as the date numeral moves into its position in the date window. If the minute hand was removed, it should be replaced on the dial assembly with the friction and cannon pinions before the dial assembly is attached to the movement. Finally, the sweep second hand is driven onto the sweep second staff just below its end, ensuring it is set below the chamfer on the top of the staff.
General| Brand | Timex |
|---|---|
| Type | Wristwatch |
| Display Type | Analog |
| Band Material | Leather |
| Movement | Quartz |
| Water Resistance | 30 meters |
| Features | Water Resistant |
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