Abbott's American Watchmaker by Henry G. Abbott

Author:Henry G. Abbott
Language: eng
Format: epub
Publisher: Skyhorse Publishing, Inc.

From the center of the wheel set off two radial lines barely 3° on each sides of the radial lines already drawn, to mark the center of the pallets, Then strike the curved dead faces of the pallets just touching the radial lines last drawn.

Now from the pallet center draw lines through the spot where the curved locking face of each pallet cuts the wheel circle. If you look at the engraving you will see that a wheel tooth is resting on the left-hand pallet. The amount of this rest is ½°, as already stated. Mark off this ½°, which gives the position of the locking corner of the pallet, and then set off another line ½°, below it, which will mark the spot for the other corner of the pallet. On the right-hand pallet, the line already drawn marks the extreme corner, and it is only necessary in order to get the locking corner, to set off a line 1½° ABOVE it.

The wheel teeth diverge from a radial line about 10°, so that only their tips touch the dead faces of the pallets.

For escaping over ten teeth, the distance between the center of the wheel and the center of the pallet staff should be equal to the diameter of the wheel; with this exception the preceding directions are applicable for setting out.

The wheel is of hard hammered brass, and for regulators is made from an inch and a half to two inches in diameter, and very light. The pallets are usually of steel, nicely fitted to the arbor, and, in addition, screwed to a collet thereon as shown. In the best clocks the acting faces are jeweled. Sometimes the pallet arms are cast of brass, and the pallets formed of solid jewels. Many good clockmakers put two banking pins in the plate, one on each side of the crutch, to prevent the pallets from being jammed into the wheel by careless handling.

The Graham escapement requires a heavy pendulum, especially if the train is comparatively rough. The clock weight must be sufficient to overcome increased resistance arising from inaccuracy of work; consequently, when the train runs freely, so much extra pressure is thrown upon the dead faces of the pallets that a light pendulum has not enough energy to unlock, and the clock stops. For clocks with shorter than half-seconds pendulums the pallets are generally made “half dead,” that is the rests, instead of being curves struck from the pallet staff hole, are formed so as to give a light recoil to the wheel.

GRAVER. A steel cutting tool used for engraving, turning, etc. The “Guaranteed” gravers, shown in Fig. 154, are unique from the fact that they cut at both ends; the handle (which is patented) is so adapted that it will accommodate the reverse ends of innumerable sizes and shapes of gravers. The various angles of points of the gravers are very excellent and cover the entire field as used both for turning and engraving.

Use of the Graver.* The

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