Drop-in resolution
ETA 2892-A2 vs Miyota 90S5: do they swap?
Whether the ETA 2892-A2 and Miyota 90S5 share a case, and what changes if you move between them.
Close in diameter, not a drop-in. The ETA 2892-A2 (25.60 mm x 3.60 mm) and Miyota 90S5 (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 ETA 2892-A2 is the slim upmarket automatic, base for many chronograph modules and higher-end pieces. The Miyota 90S5 is the open-heart member of the 90 series, showing the balance through the dial.
They differ in diameter (25.60 mm vs 26.00 mm), height (3.60 mm vs 3.90 mm), calendar layout (centre seconds, date at 3 vs open heart, no date). Same 25.60 mm diameter as the 2824-2 but only 3.60 mm tall, a full millimetre thinner. It is a slimmer platform, not a drop-in for a 2824 case, because the reduced height changes hand heights and case seating.
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.