MovementSwap

Different footprints. The Miyota 82S5 is 26.00 mm x 5.67 mm and the Seiko NH34 (TMI NH34A) is 27.40 mm x 5.32 mm, so they do not share a case. This is a choice between platforms, not a swap. Published dimensions, layout and the checks before you swap one for the other.

Updated 05 September 2026.

Drop-in resolution

Miyota 82S5 vs Seiko NH34 (TMI NH34A): do they swap?

Whether the Miyota 82S5 and Seiko NH34 (TMI NH34A) share a case, and what changes if you move between them.

No drop-in

Different footprints. The Miyota 82S5 is 26.00 mm x 5.67 mm and the Seiko NH34 (TMI NH34A) is 27.40 mm x 5.32 mm, so they do not share a case. This is a choice between platforms, not a swap.

The Miyota 82S5 is the small-seconds open-heart 8200 member, in decorated entry automatics. The Seiko NH34 (TMI NH34A) is the affordable modding GMT automatic, adding a caller-GMT hand to the NH35 base.

They differ in diameter (26.00 mm vs 27.40 mm), height (5.67 mm vs 5.32 mm), calendar layout (small seconds, open heart, no date vs centre seconds, GMT 24h hand, date at 3), winding behaviour. An 8200-family open-heart caliber at 26.00 mm x 5.67 mm with small seconds rather than the 82S0's central seconds. It shares the family footprint but needs its own small-seconds, open-heart dial.

Matching diameter and height is necessary but not sufficient. A donor is only a true drop-in when the dial-foot positions, hand-hole sizes, stem length and calendar layout also match. Two movements can share a case and still need a new dial, re-broached hands or a cut-to-length stem.

Calibers and lookups

Miyota 82S526.00 mm x 5.67 mm
Seiko NH34 (TMI NH34A)27.40 mm x 5.32 mm
Donor movement for Miyota 82S5drop-in lookup
Donor movement for Seiko NH34 (TMI NH34A)drop-in lookup

Questions and answers

Miyota 82S5 vs Seiko NH34 (TMI NH34A): do they swap?

Different footprints. The Miyota 82S5 is 26.00 mm x 5.67 mm and the Seiko NH34 (TMI NH34A) is 27.40 mm x 5.32 mm, so they do not share a case. This is a choice between platforms, not a swap.