A Jewelled Calendar
The Timex Model 75 is an 11¼ ligne by 9¼ ligne, 21 jewel calendar movement featuring rugged two plate construction. The Model 75 is readily distinguished from other Timex movements by the number of jewels and the small, gracefully decorated movement plate.
Whereas most watches utilize bridges, Timex has constructed the Model 75 movement with full plates to take advantage of the accuracy inherent in this type of design. This accuracy insures complete interchangeability of the escapement and gear train without the need for selective fitting and adjustments which complicate the repair of most watches.
Another important feature is the escapement. Timex developed a jewelled lever escapement which functions exactly as the conventional escapements but eliminates the danger of loose pallet stones. In conventional jewelled club-tooth lever escapements the pallet stones lie horizontal to the plane of the lever and are normally shellacked in place, which leads to frequent loosening of the stones during cleaning and so to readjustment. The Timex design instead uses pallet stones vertical to the pallet lever, driven permanently in place. Since they are not fixed with shellac or other adhesives they will not loosen during cleaning and will not require adjustment, thus retaining full accuracy in the escapement.
Exploded View
The Model 72 list with the Model 25 calendar parts folded in.
Where the Servicing Lives
The Model 75 manual carries no disassembly, cleaning or reassembly instructions of its own. In its own words, servicing techniques, parts and so on are identical to those shown for the Model 72 movement and the M-25 calendar mechanism. So rather than restate them here, the two guides that hold them:
Disassembly, the cap jewels and their reground screwdriver, cleaning, lubrication and reassembly. The Model 75 shares all of it.
Model 72 Guide →The date wheel, date ring, detent spring and the indexing check. Every calendar part in the Model 75 is the Model 25’s.
Model 25 Guide →The Cap Jewel and Retaining Ring
The Model 75 carries the Model 72’s removable cap jewels. The exploded plate calls out the retaining ring, 495/1, and the cap jewel itself, 645, in a boxed detail. Removal is on page 72.6.
