Raketa 2628.H Restoration: Soviet Full Calendar Watch with Instantaneous Day-Date Change

Raketa 2628.H: Restoration of a Soviet Full Calendar Movement

"Every neglected timepiece carries potential beneath its accumulated grime..."
— Observations from the workbench

Certain watches arrive at the bench in condition that tests one's commitment to the restoration craft. The subject of this documentation presented initially as an unpromising mass of accumulated debris, its chrome surfaces obscured beneath years of environmental exposure and human contact. Yet experienced technicians recognize that external neglect frequently conceals internal preservation, particularly in well-sealed cases. The transformation that follows demonstrates both the resilience of Soviet engineering and the satisfaction inherent in returning a worthy caliber to service.

The movement within this battered case proved to be the Raketa 2628.H, one of the more sophisticated calibers produced by the Petrodvorets Watch Factory. This nineteen-jewel mechanism incorporates a complete calendar displaying both date and day of week, with instantaneous advancement of both indicators at midnight. The engineering required to achieve simultaneous instantaneous change of two calendar displays represents genuine technical accomplishment, making this caliber particularly worthy of careful restoration.

Initial Assessment and Disassembly

Preliminary examination revealed a case of considerable interest beneath its unappealing exterior. The construction employs a threaded ring securing the case back against a gasket, providing genuine dust resistance. The crystal mounting follows an unusual approach: the mineral glass rests directly against the case middle, held in position by the dial and movement assembly pressing from within. This arrangement, while unconventional, creates an effective seal when properly assembled.

The movement mounts within a split nylon shock-absorbing ring, a period-appropriate solution for protecting the caliber from mechanical impact. These polymer rings occasionally become brittle with age, crumbling during disassembly, but this example retained adequate elasticity for continued service. The crown showed significant wear, necessitating replacement, but this represented the only component requiring substitution rather than mere cleaning.

Case back removed showing internal contamination — Case interior following back removal, demonstrating the extent of contamination requiring attention

Case components soaking in solvent — Case components submerged in used solvent for initial degreasing, the first step toward restoration

The crystal required careful handling given its distinctive character. One surface carries the watch's branding and graphic elements applied directly to the glass, making this component irreplaceable should damage occur during cleaning.

Crystal exterior showing contamination — The crystal exterior prior to cleaning, surface contamination obscuring the glass beneath

Crystal interior with printed markings — The crystal interior bearing printed markings, a component demanding preservation given its irreplaceability

Crystal after initial cleaning — The crystal following preliminary cleaning, its character beginning to emerge

Movement Examination

Removing the movement from its protective ring revealed the most encouraging discovery of the project. Despite the case exterior's deplorable condition, the dial remained in exceptional state, its surface unmarked by the contamination surrounding it. This observation confirms the case design's effectiveness: whatever moisture and particulate matter accumulated on external surfaces, the sealing system prevented ingress to the movement chamber.

Movement with dial showing excellent preservation — The movement and dial revealed in unexpectedly fine condition, the case having protected its contents effectively

Movement in shock mount ring — The movement within its nylon shock-absorbing mount, the polymer retaining adequate flexibility

Movement extracted from mount — The caliber freed from its mounting ring, ready for hand removal and disassembly

The seconds hand on Raketa calibers 2614 and 2628 presents a particular concern during service. These hands mount on an extended post requiring a specific fitting unavailable from standard parts sources. Losing or damaging this component effectively renders the watch incomplete, as replacements prove extremely difficult to source. Removal therefore proceeds with appropriate caution.

Seconds hand removal in progress — Careful extraction of the seconds hand, its extended post requiring gentle manipulation

Seconds hand removed safely — The seconds hand successfully removed, its distinctive tall post visible

The main hands follow, employing a technique that simultaneously protects the dial and captures the hands against accidental loss. A thin film placed over the dial creates a barrier between the lifting tool and the delicate dial surface while preventing the hands from launching across the workbench when released from their friction fit.

Protective film over dial for hand removal — Protective film positioned over the dial before main hand removal

Hands being lifted with film protection — Hands lifting against the protective barrier, preventing both dial damage and component loss

Hands captured on protective film — Both hands captured safely on the film surface following removal

Dial foot screw location — The dial foot securing screw, partially loosened to release the dial from the movement

Movement ready for complete disassembly — The movement prepared for complete disassembly, dial removed and stored safely

Crystal Restoration

The acrylic crystal presented significant surface wear requiring polishing before reassembly. The technique employed involves a soft cloth dampened with water and common toothpaste, the mild abrasive action gradually removing accumulated scratches through patient repetition. Approximately fifteen hundred to two thousand strokes, representing perhaps fifteen minutes of consistent effort, typically restore optical clarity to acrylic crystals of this type. The process demands patience rather than skill, yielding results that justify the time invested.

Crystal polishing setup with toothpaste — Crystal polishing arrangement: soft cloth, water, and quality toothpaste providing the mild abrasive action required

The Raketa 2628.H Caliber

Following overnight soaking and ultrasonic cleaning, the movement components presented in excellent condition for reassembly. The caliber 2628.H represents one of the finest Soviet watch movements, incorporating features that commanded premium positioning in Western markets while remaining accessible domestically. The nineteen-jewel specification indicates comprehensive bearing support throughout the gear train and escapement.

Cleaned movement components laid out — The caliber 2628.H components following cleaning, arranged for systematic reassembly

Main plate after cleaning — The main plate restored to pristine condition, ready to receive its components

The shock protection system employs lyre-shaped retaining springs securing the balance cap jewels within sprung chatons. This assembly requires careful handling during service, with the components removed for cleaning and lubrication before reinstallation.

Balance cap jewel assembly — The balance shock protection assembly before service, the cap jewel visible within its sprung setting

Cap jewel cleaned and lubricated — The cap jewel assembly following cleaning and lubrication, the chaton showing no oxidation despite years of service

Cap jewel reinstalled with lyre spring — The cap jewel assembly reinstalled with its lyre-shaped retaining spring

Reassembly Procedure

Reassembly begins with the keyless works, establishing winding and setting functions before other systems are installed. The clutch assembly and winding pinion mount first, followed by the setting levers and their associated spring.

Clutch and winding pinion installed — The clutch assembly and winding pinion positioned on the main plate

Setting levers and spring installed — Setting levers and spring in position, establishing the keyless works foundation

Keyless works cover installed — The keyless works secured beneath their cover plate

An interesting detail appears at this stage: one of three jewels visible in the plate serves as a bearing for the day-of-week disk rather than a functional movement bearing. The caliber actually contains twenty-two jewels total, but three qualify as non-functional under international standards because they support only the calendar disk rather than contributing to timekeeping accuracy. Official specifications therefore list nineteen jewels, though the additional three are physically present and clearly visible.

Non-functional calendar disk jewel — One of three non-functional jewels supporting the calendar disk, excluded from the official jewel count per international standards

The gear train follows standard Soviet practice, with the center wheel receiving attention first. All jeweled bearings receive Moebius 8000 synthetic oil, while the mainspring and keyless works components use the heavier B-1 grease formulation appropriate for their higher-load applications.

Gear train components ready for installation — Gear train components prepared for installation, each requiring appropriate lubrication

Center wheel installation — The center wheel positioned in its jeweled bearings with fresh lubrication

Center wheel bridge installed — The center wheel bridge securing the first train wheel in position

The mainspring barrel presents a notable detail. While the barrel arbor runs in a hardened metal insert on the bridge side, the plate-side bearing employs a brass bushing rather than a jewel. This represents a cost-reduction measure common in Soviet calibers of this grade, though the substantial construction of the plate hole minimizes the practical impact on service life.

Mainspring barrel assembly — The mainspring barrel following lubrication, its S-profile spring freshly greased

Barrel arbor bearing detail — The barrel position showing the hardened insert in the bridge and the calendar disk jewel nearby

Barrel installed in movement — The mainspring barrel positioned in the movement

Barrel bridge installed — The barrel bridge securing the mainspring container

The remaining train wheels install in sequence, followed by the train bridge, pallet fork assembly, and finally the balance wheel. Each assembly step concludes with verification of free rotation before proceeding to the next.

Train wheels positioned — The gear train wheels arranged in their bearings awaiting the bridge

Train bridge installed — The gear train bridge securing all wheels, pivots verified for free movement

Pallet fork assembly installed — The pallet fork assembly mounted, completing the escapement installation

Balance wheel installation — The balance wheel returning to its position, the moment of truth approaching

Balance cap jewel service — Final lubrication of the upper balance cap jewel before completing assembly

Movement running after assembly — The movement alive and running, balance wheel oscillating with healthy amplitude

Calendar Assembly

The calendar mechanism distinguishes this caliber from simpler date-only movements. A nine-pointed star wheel controls the day-of-week indication, its precise geometry ensuring clean single-step advancement with each daily cycle. This component demands careful handling, as any deformation of the star points compromises the mechanism's reliable function.

Day correction star wheel — The nine-pointed star wheel governing day-of-week advancement, its geometry critical to proper function

Calendar disks installed — The calendar disks installed with their spring washer, completing the calendar assembly

The dial returns following gentle cleaning with diluted shampoo and a soft brush, a treatment it tolerated without damage to its printed surfaces. Brief solvent contact also proved harmless, removing the slight yellowing that had developed during decades of storage. Hand installation concludes the movement work, with careful attention to synchronizing the hands with the calendar change position.

Dial installation with gloved hands — Dial installation proceeding with gloved hands to prevent contamination of the pristine surface

Hands installed with calendar synchronized — Hands installed with the calendar synchronized to change at midnight, the cleaned case visible nearby

Case Restoration and Final Assembly

The case components, having soaked overnight in used solvent, emerged free of their accumulated grime. Light polishing with appropriate chrome-cleaning compounds restored surface luster without breaking through to the brass substrate beneath. The goal in such work is cosmetic improvement rather than aggressive material removal, preserving the remaining plating while eliminating surface oxidation and contamination.

Case components cleaned and ready — Case components following cleaning and light polish, the crystal restored to clarity

Watch assembly in progress — Final assembly proceeding with movement entering the prepared case

Movement installed in case — The movement secured within the case, threaded back ring engaging

Case back secured — The case back secured, restoration nearing completion

A replacement crown completed the external restoration, the original having worn beyond acceptable appearance. The new component harmonizes with the case finish while providing the positive engagement necessary for reliable winding and setting.

New crown installed — The replacement crown installed, restoring both function and appearance

Case detail showing minor wear — Minor remaining wear on the case, evidence of honest use that does not affect function

Results

The completed restoration transformed an apparently hopeless specimen into a fully functional timepiece worthy of regular wear. Timing machine verification confirmed excellent performance, with the movement running well within acceptable parameters for a caliber of this specification.

Restored watch on wrist — The restored Raketa on the wrist, its transformation complete

Timing machine results — Timing machine verification confirming healthy rate and amplitude

Final glamour shot of restored watch — The completed restoration displaying its recovered elegance

Watch artistic presentation — The Raketa 2628.H returned to service, its full calendar function ready for daily use

Technical Notes

The Raketa caliber 2628.H merits recognition among the more accomplished Soviet movement designs. The full calendar with instantaneous advancement of both day and date indicators required sophisticated engineering to achieve reliable function. The nineteen functional jewels, supplemented by three non-functional calendar disk bearings, indicate comprehensive attention to friction reduction throughout the mechanism.

The case construction, while not claiming water resistance in any meaningful sense, provides excellent dust protection through its threaded back and gasket arrangement combined with the unusual crystal mounting system. The nylon shock ring offers additional protection appropriate for a watch intended for daily wear rather than specialized applications.

Restoration work on heavily soiled specimens requires patience during the cleaning phase but frequently rewards that patience with movements in better condition than external appearances suggested. The case protects its contents; accumulated external contamination often indicates effective sealing rather than internal degradation. This project exemplified that pattern, with the deplorable external condition concealing a dial and movement requiring only routine service rather than major intervention.

The replacement of worn components, in this case limited to the crown, represents standard practice when original parts have degraded beyond functional acceptability. Maintaining period-appropriate appearance while ensuring reliable operation requires balancing preservation instincts against practical necessity. A watch exists to tell time; non-functional originality serves no useful purpose.