Drop-in resolution
Miyota 82S7 vs Miyota 9012: do they swap?
Whether the Miyota 82S7 and Miyota 9012 share a case, and what changes if you move between them.
Close in diameter, not a drop-in. The Miyota 82S7 (26.00 mm x 5.67 mm) and Miyota 9012 (26.00 mm x 3.90 mm) are near in size but differ in height, dial feet or layout, so moving between them means a new dial, hands and often a case adjustment.
The Miyota 82S7 is the fullest 82S member, adding a 24-hour or day/night indicator at 9. The Miyota 9012 is a 90-series premium automatic with a 24-hour sub-hand and date.
They differ in height (5.67 mm vs 3.90 mm), beat rate (21,600 A/h (3 Hz) vs 28,800 A/h (4 Hz)), calendar layout (small seconds, open heart, 24h at 9, no date vs centre seconds, date at 3, 24h sub-hand), winding behaviour. An 8200-family open-heart caliber at 26.00 mm x 5.67 mm with small seconds and a 24-hour indicator at 9. It shares the family footprint with the 82S5 but adds the 24h register, so it needs its own 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.