Drop-in resolution
Miyota 9019 vs Seiko 7S36: do they swap?
Whether the Miyota 9019 and Seiko 7S36 share a case, and what changes if you move between them.
Different footprints. The Miyota 9019 is 26.00 mm x 3.90 mm and the Seiko 7S36 is 27.40 mm x 5.60 mm, so they do not share a case. This is a choice between platforms, not a swap.
The Miyota 9019 is a slim no-date 90-series automatic, in clean-dial dress and field watches. The Seiko 7S36 is the extra-jewel sibling of the 7S26, in many Seiko 5 sports models.
They differ in diameter (26.00 mm vs 27.40 mm), height (3.90 mm vs 5.60 mm), beat rate (28,800 A/h (4 Hz) vs 21,600 A/h (3 Hz)), calendar layout (centre seconds, no date, slim vs centre seconds, day and date at 3), winding behaviour. A 90-series slim automatic at 26.00 mm x 3.90 mm without date, sharing the 9015/9039 footprint and dial feet. It drops into a 90-series case built for a clean no-date 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.