Making the Anchor
American Watchmaker and Jeweler (1892)
This form of anchor presents no difficulties in making it, but, of course, more care is necessary than in an ordinary escapement. The points requiring the most care are the locking faces, which as before stated, must be circles concentric to the the center of the anchor motion. A piece of good steel plate thoroughly annealed, is to be used to make the anchor from. This steel plate must be smoothed, and the angles of the anchor carefully outlined by using a sharp pointed marker. The surplus metal may be removed by drilling a number of holes or it may be sawed out by using a jewelers' saw. The steel plate should be thick enough that the impulse faces will at all times overlap the escape wheel teeth. For an astronomical clock or regulator it will be found of advantage to make the anchor as shown in Fig. 153, which will be found quite solid if the screws are as closely fitted as they should be. In hardening it will be quite sufficient if the pallets are hardened, as there is no wear except at these points, and there is of course no distortion to be corrected. The locking surfaces may be ground concentric by mounting the anchor upon an arbor which must be perfectly upright, which will fit the arbor hole with sideshake, but yet so it can be moved around. This arbor may be mounted in place of the T-rest of an American lathe, or what is better an attachment may be put on the the slide rest so that the anchor may be brought up to a good sized copper lap, to which carborundum is applied and by rotating the anchor upon this arbor, the locking surfaces may be ground off concentric. By using a zinc or tin lap with diamantine, the same method may be employed for polishing.
What Has Changed in the Last Century
When the American Watchmaker and Jeweler set this out in 1892, hand-cutting and lapping a steel anchor was the route to the best timekeeping there was, and the writer's aside about "an astronomical clock or regulator" points to the top of the trade. That role has gone: the free-pendulum Shortt clock of the 1920s took over from ordinary regulators in observatories, quartz oscillators displaced pendulums in the 1930s, and the caesium atomic clock of 1955 ended the mechanical era for scientific timekeeping altogether. Where escapement parts are still made for wristwatches, they are stamped, wire-cut or, since the early 2000s, etched from silicon wafers rather than sawn from annealed plate and ground on a copper lap. The bench method described here survives chiefly in restoration work and in horological schools, where the tools named — the jeweller's saw, carborundum, diamantine — are still recognisable.
Written for this edition, 2026.