Gas Heater
This heater, shown in Fig. 138, is to take the place of a forge in heating and tempering small articles. With a full pressure of gas, a piece of steel half an inch in diameter can be heated sufficiently to harden in about six minutes. It does not heat to a degree that will injure the quality of steel; which makes it very valuable for heating small pieces. Watchmakers will find in its use great convenience as well as economy of time and fuel; and also, that tools heated by it will be tougher than when heated in a forge in the usual way.
Put on sufficient gas to prevent the flame from descending into the tube. For heating larger pieces the flame should be nearly three inches wide. The upper ends of the curved side pieces should not be more than one-quarter of an inch apart. The article to be heated should be held in the upper part of the flame above the central blue part and parallel with it. The larger the piece to be heated the further it should extend into the flame. The heater should be located in a dark place, and supports may be provided for greater convenience in heating heavy articles.