Drop-in resolution
ETA 2836-2 vs Sellita SW330-1: do they swap?
Whether the ETA 2836-2 and Sellita SW330-1 share a case, and what changes if you move between them.
Close in diameter, not a drop-in. The ETA 2836-2 (25.60 mm x 5.05 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 ETA 2836-2 is the day-date sibling of the 2824-2, in dressier and tool watches that show the weekday. The Sellita SW330-1 is the Sellita caller-GMT automatic, the drop-in alternative to the ETA 2893-2.
They differ in height (5.05 mm vs 4.10 mm), calendar layout (centre seconds, day and date at 3 vs centre seconds, GMT 24h hand, date at 3). Same 25.60 mm diameter as the 2824-2 but taller at 5.05 mm because of the added day disc. A 2824-2 will not fill a 2836 dial: the day window sits empty.
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.