Drop-in resolution
Miyota 90S5 vs Sellita SW330-1: do they swap?
Whether the Miyota 90S5 and Sellita SW330-1 share a case, and what changes if you move between them.
Close in diameter, not a drop-in. The Miyota 90S5 (26.00 mm x 3.90 mm) and Sellita SW330-1 (25.60 mm x 4.10 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 90S5 is the open-heart member of the 90 series, showing the balance through the dial. The Sellita SW330-1 is the Sellita caller-GMT automatic, the drop-in alternative to the ETA 2893-2.
They differ in diameter (26.00 mm vs 25.60 mm), height (3.90 mm vs 4.10 mm), calendar layout (open heart, no date vs centre seconds, GMT 24h hand, date at 3). A 90 series caliber at 26.00 mm x 3.90 mm with an open-heart aperture that exposes the balance. It shares the 9015 footprint and dial feet but needs a dial cut for the open-heart window.
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.