The Escape Wheel

American Watchmaker and Jeweler (1892)

The wheel is made of brass or gold, which should be well hammered to harden it and give it rigidity, which is very essential, as it must be left as light as possible. The teeth are cut by a cutter whose cutting edge conforms to the circle of the wheel and the back of the teeth are cut by a cutter of suitable form. After the teeth are cut a hole is bored through a plate, which may be of steel and then hardened, which corresponds to the inner circle of the rim of the wheel and concentric with this a recess is turned out into which the escape wheel will just enter freely. The arms of the wheel are to be carefully worked out by hand, using small files and working carefully so as not to distort the metal. The greater part of the metal between the arms may be removed by drilling several holes which will expedite the work somewhat. For finishing up the arms a guide can be made by turning a disc of steel whose outside diameter corresponds to that of the escape wheel, so that it may enter the same recess, and then cutting almost half of it away, or half the width the arm is to be over half the diameter, also leaving a portion remaining, which will correspond to the hub of the wheel. If the piece before mentioned was made of steel and hardened it will act as a guide for forming the inner circle of the rim. After the arms are cut out and nicely smoothed the wheel may be cemented into an accurately fitted recess turned into a cement brass and the arms thinned down to about half the thickness the rest of the wheel is by turning out with the slide rest or other suitable attachment, using a very keen tool which will leave a smooth and polished cut. The points of the teeth should not be left sharp, but should be imperceptibly rounded. Sometimes the recessing is carried out as far as the base of the teeth, leaving a sharp angle, and in others it is carried to the points of the teeth in a gentle curve, beginning at their base. This latter form makes the lightest wheel, but is somewhat more difficult to make and does not look quite so nice as the first form, as the flat top of the rim and teeth may be highly polished upon an agate polishing stone, such as is used to polish jewel settings, etc. The cutters used for cutting the teeth should leave a smooth, polished cut, as the teeth should not be changed from what the cutter left them.