A Mechanical Alarm is a complication that produces an audible signal at a preset time using nothing but springs, levers, and a vibrating hammer, no quartz buzzer involved. Early wrist attempts trace to Eterna in the 1910s, but the watchmakers fought three problems for decades: the alarm's vibration disturbed timekeeping, the sound stayed too faint, and the alarm spring drained the main barrel. The fix lay in dedicating energy to the alarm itself. A cam trips a lever, the lever releases the alarm mainspring, and a hammer beats against a surface hundreds of times in a few seconds. What it strikes defines the sound: older designs where the hammer taps a post on the caseback buzz quietly, while a circular gong wrapped around the movement, closer in spirit to a minute repeater, gives a clearer, louder ring.
Two references set the tone for the category. The Vulcain Cricket arrived in 1947 with the hand-wound caliber 120, built around two barrels, one for the time and a second purely for the alarm, wound in opposite directions from a single stem. Its resonance caseback makes it genuinely loud, and gifting one to President Truman in 1952 earned it the nickname the Presidents' Watch. Jaeger-LeCoultre's Memovox followed in 1951 with an inner setting disc, added the first automatic alarm in 1956, and in 1959 produced the Deep Sea Alarm, the first dive alarm. Today modern Crickets start around $3,900, with a Cricket President near $5,000; the Tudor Heritage Advisor in steel and titanium sat around $6,000 when new; JLC's Master Control Memovox runs from roughly $11,000 in steel, while the Memovox Timer, with its peripheral gong and visible hammer, sits near $15,600. Ball's Roadmaster M Model A, with its AlarmMATIC automatic alarm, lands around $6,299.
When buying, start with how the sound is made. A true gong is both sweeter and more audible than a post-and-buzzer setup, but it asks for proper servicing. Dual-barrel systems let the alarm sound at full strength without weakening the going train, while single-barrel solutions are slimmer but borrow power from the timekeeping. On vintage pieces, an original, correctly adjusted hammer and gong spring matter enormously, since a badly serviced alarm wheezes rather than rings. This category suits the collector who wants a tactile, audible reminder independent of any calendar, and who enjoys feeling the mechanism work. Do not expect smartphone convenience: winding, setting, and the sound itself demand intention, which is precisely the appeal.
There are sub-types worth knowing. Simple caseback-buzzer pieces from 1960s Swiss and Japanese makers are the most affordable entry point, while gong-equipped manufacture calibers show off the craft of sound. Dive alarms such as the Memovox Polaris and Deep Sea form their own niche; originals are scarce and dear, making modern reissues a more reachable way in.