From WWII on, the US government wrote specifications for wrist watches to be worn by pilots and soldiers. Great American companies like Hamilton, Elgin, Waltham, and Benrus made mechanical watches at scale for decades to be supplied to GIs.
The following image is from a military specification for a field watch from the early 60s:
Hamilton and others continue to make mechanical watches that follow this spec, but I don’t have the budget at the moment to buy one of those. So I decided to do a watch mod project aimed at producing a milspec watch.
The Seiko SKX is the watch with the most options in terms of available crystals, hands, bezels, etc. for modding, but at around $200 it’s pricey to get started on. Starting as low as $55, the SNK presents the cheapest way to get a decent mechanical with a fair number of mod options — so that’s where I decided to start.