SEIKO (SII) NH05/NH06 Third Wheel

Product Description

The SEIKO (SII) NH05/NH06 Third Wheel is a genuine Japanese-made component for these compact automatic movements, measuring 7¾”’ (approx. 17.5mm) in diameter . As a key part of the gear train, the third wheel transmits power from the center wheel onward to the fourth wheel and escapement, playing a critical role in maintaining stable amplitude and accurate timekeeping . This brand new original part is essential for watchmakers restoring proper power transmission and timekeeping accuracy when the original gear train component becomes worn or damaged.

Features & Function

• Genuine Seiko/SII part – authentic Japanese-made component for NH05 and NH06 movements 

• Gear train component – transmits power from the center wheel to the fourth wheel and escapement

• 21-jewel movement – part of the 21-jewel NH0 series architecture 

• NH0 family compatibility – designed for the compact 7¾”’ NH05 (date) and NH06 (day-date) calibers 

Specifications

• Compatible Movements: Seiko NH05 (date), NH06 (day-date) 

• Movement Family: NH0 Series

• Movement Size: 7¾”’ (approx. 17.5mm) 

• Movement Height: 5.92mm 

• Jewels: 21 

• Frequency: 21,600 vph (3 Hz) 

• Power Reserve: >40 hours 

• Crown Positions: Normal (manual winding), 1st click (date/day setting), 2nd click (time setting) 

• Origin: Japan

Applications

• Service and overhaul – replacing worn or damaged third wheels in NH05/NH06 movements

• Gear train restoration – ensuring stable power delivery to the escapement for accurate timekeeping 

• Suitable for professional watchmakers and experienced repair technicians

FAQs

1. Is this a genuine Seiko/SII part?

Yes, this is a genuine Seiko (SII/TMI) factory part made in Japan. The NH05 and NH06 are manufactured by Seiko Instruments Inc. (SII) and distributed by Time Module Inc. (TMI) .

2. Which movements is this third wheel compatible with?

This third wheel is designed for Seiko NH05 and NH06 movements. The NH05 features a date display, while the NH06 adds a day-date complication, but both share the same basic gear train architecture .

3. What are the signs that the third wheel needs replacement?

Common signs include worn or damaged teeth, irregular timekeeping, low amplitude, or visible wear during movement inspection. A qualified watchmaker can diagnose these issues during servicing.

Why Choose SOFLY Watch Parts?

• Fast worldwide shipping within 3 business days.

• Competitive pricing on Seiko/Hattori calibers.

• 3,000+ watch movements and parts in stock.

• Trusted by watchmakers worldwide.

• Personalized sourcing support via [email protected] or WhatsApp +86 18620212114.