Seiko 2517B – Technical Guide

The Seiko 2517B is a manual-winding mechanical movement with a date display, introduced in the early 1970s as an updated version of the earlier 2517A. Specifically developed for ladies' wristwatches, this ultra-compact caliber was part of the trusted 25xx movement family, known for its mechanical simplicity, slim profile, and long-lasting reliability. The 2517B continued Seiko’s legacy of delivering durable and elegant movements designed for small, refined cases without sacrificing accuracy.

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1. Technical Specifications

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2. Key Features

• Time-and-date manual-wind movement built for ladies' vintage watches

• Date display located at 3 o’clock, integrated discreetly into compact dial designs

• Non-quickset date: date is advanced by rotating the hands through midnight

• Refined update over the 2517A, with improved manufacturing tolerances and balance control

• High beat rate (21,600 bph) gives better accuracy and smoother hand movement

• 17 jewels placed to reduce friction on the gear train and escapement

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3. Calendar Operation

Setting the Date:

1. Pull the crown to the time-setting position.

2. Rotate the hands forward past midnight to change the date.

3. Repeat the 24-hour cycle to reach the desired date.

4. Push the crown back in when complete.

⚠️ This is a non-quickset mechanism — avoid turning hands backward past midnight repeatedly, as it may damage the date jumper or calendar teeth.

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4. Movement Construction

Dial Side:

• Date disk

• Date jumper and spring

• Calendar driving wheel

• Hour and minute wheel

• Cannon pinion and clutch assembly

Train Side:

• Manual winding mechanism: ratchet wheel, crown wheel, click spring

• Mainspring barrel

• Gear train: center, third, fourth, and escape wheels

• Pallet fork and balance assembly

• Regulator and Diashock shock protection system

Despite the compact dimensions, the movement is designed to be durable and serviceable.

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5. Servicing Guidelines

Recommended Interval:

• Every 4–6 years

Servicing Process:

1. Disassemble: Carefully remove hands, dial, and all mechanical components

2. Clean: Ultrasonic cleaning of metal parts; hand-clean delicate items like hairspring

3. Inspect: Check jewels, pivots, and mainspring condition

4. Lubricate: Lightly oil pivots, escapement, and date mechanism

5. Reassemble: Align date jumper correctly to avoid misalignment

6. Regulate: Use a timing machine to set rate and beat error

7. Expected Performance: Amplitude ~250°, accuracy within ±20–30 sec/day

⚠️ Avoid over-oiling. These small calibers require minimal but precise lubrication.

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6. Common Issues & Fixes

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7. Watch Applications

The Seiko 2517B was widely used in Seiko ladies’ watches during the early to mid-1970s. Typical features include:

• Small case sizes (≈18–24 mm)

• Gold-plated or stainless steel cases

• Acrylic crystals

• Dials with minimal text, often with:

  • Applied indices

  • Baton or dauphine hands

  • Date window at 3 o’clock

Common case references include:

• 2517-0030

• 2517-5000

• 2517-7000

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8. Conclusion

The Seiko 2517B is a beautifully engineered, compact mechanical movement that offered elegant timekeeping with practical functionality. As an evolution of the 2517A, it maintained Seiko’s commitment to performance, precision, and long-term serviceability—despite its small size.

Perfectly suited for collectors and watchmakers restoring vintage ladies’ timepieces, the 2517B remains a reliable and charming example of Seiko’s golden era of mechanical watch design. With proper care, this little caliber will continue ticking gracefully for decades to come.

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