Making the Anchor
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.