The Deadbeat

The seconds hand that doesn't shiver — and why that matters in a precision regulator.

The problem with recoil

In a recoil escapement, the escape wheel doesn't simply pause between beats: it briefly reverses. The locking stone on the anchor pushes back against the wheel tooth at the moment of impulse, and the wheel ticks momentarily backward before advancing. Watch a seconds hand on a recoil clock and you can see it — a slight retreat before each forward step. It looks like imprecision because it is imprecision. The recoil disturbs the pendulum's arc, adds wear at the tooth faces, and makes the hand useless for reading seconds accurately.

George Graham solved this in London around 1715. His answer was the deadbeat escapement — so named because the escape wheel, once locked, stays absolutely still until released.

What Graham changed

Graham kept the anchor form but redesigned the pallets. In a recoil anchor the locking faces are slightly convex, angled so that the tooth tends to push the pallet backward — and does. Graham made his locking faces concentric with the pallet arbor: arcs centered exactly on the pivot point. A tooth resting on one of those faces cannot push the pallet in any direction, because the surface is perfectly tangential to the force. The wheel is locked dead. It does not recoil; it waits.

The impulse faces remain angled, as in any anchor, so the wheel can still deliver energy to the pendulum on the way through. But the moment the tooth drops onto the locking face after impulse, all motion stops — instantly and completely. The seconds hand lands on each division and holds there, still.

The cost is modest friction on the locking face during dwell, which a recoil anchor doesn't have in quite the same way. Graham compensated by finishing those faces with particular care. High-grade regulators — the precision clocks used in observatories — adopted the deadbeat almost universally from the early eighteenth century onward, and it remained the escapement of choice for serious pendulum clocks for the next two centuries.