Drop-in resolution
Donor movement for the Seiko 4R34
Which movement drops into a Seiko 4R34 case, and what has to match beyond the footprint.
Drop-in available. The Seiko NH34 (TMI NH34A) shares the Seiko 4R34 footprint (27.40 mm x 5.32 mm, centre seconds, GMT 24h hand, date at 3) and is the standard donor.
The Seiko 4R34 sits in the Seiko NH34 / 4R34 GMT footprint (27.40 mm x 5.32 mm, GMT hand) group. The Seiko NH34 (TMI NH34A) share its casing diameter, height and calendar layout, so a case and dial built for the Seiko 4R34 accept them with the correct dial and hands.
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.