Seiko Spare Part 315006 (1 piece) – Balance Staff (天真 / Balance Staff) for Seiko 88 Stopwatch (Cal. 8800A–F) – NOS

Original Seiko Balance Staff (天真 / Balance Staff) with part number 315006 from New Old Stock (NOS) for Seiko "88" stopwatches (caliber family 8800 – versions 8800A, 8800B, 8800C, 8800D, 8800F, among others). Offered is a single piece, taken from an original Seiko parts package ("5 PCS").

The balance staff is one of the central and most heavily stressed components of the movement: it carries the balance wheel with hairspring, and its fine pivots run in the (cap) jewels. A broken or worn balance staff is a common reason for servicing – original NOS staffs are therefore particularly sought after.

Regarding application: The Seiko 88 series are mechanical stopwatches (calibers 88 / 8800, approx. 1960s–1980s) which, depending on the version, ran at 18,000 or 36,000 vibrations/hour and offered, among other things, 1/5- or 1/10-second display, 30-minute register, and sometimes flyback. Original, unused spare parts for these stopwatches are hard to find today – relevant for watchmakers and collectors who are restoring a Seiko stopwatch.

The part is unused; storage may have caused minor, purely cosmetic traces that do not affect functionality.

Note on assignment: Before installation, please compare the shaft dimensions (pivot diameter, overall height, plateau/roller seat) with the required balance staff or the specific 8800 version.

Manufacturer: Seiko (K. Hattori & Co., Japan).

Warranty (used) This is an original part (NOS) stored for decades. The statute of limitations for claims for defects (statutory warranty) is 12 months from delivery.

Note Before installation, please compare the shaft dimensions and fit with the required balance staff; installation should be done professionally.