Formation of Dross Upon the Surface of Linotype Metal.
Dross is a compound formed by the action of air upon molten metal. The oxygen contained in the atmosphere attacks most metals with which we are acquainted. The formation of this oxide takes place more rapidly and in larger quantities the higher the temperature of the metal.
This oxidation only occurs upon the surface of molten metal where the air has access and not in the center of the molten mass. It is easy to skim this dross from the metal by means of an iron ladle. It can then be reduced to metal during the operation of melting the slugs into blocks already described.
If this is done little loss will result. The principle of its reduction to the metallic state is this:
If such dross is heated in contact with carbonaceous material, such as rosin, the carbon and resulting gases formed in the process take away the oxygen contained in the dross, liberating the metal.
Care of Friction Clutch.
Care should be taken to keep the inside rim of pulley and clutch leather shoes free from oil; if not, the clutch will slip and fail to turn machine over. The clutch and pulleys should be taken off every two weeks and cleaned and oiled; if not, they will become dry on the shaft and cause the mold disk to carry over when the machine stops.
To take off the clutch and pulleys unscrew the nut E (Fig. 13) and loosen screw which holds clutch on the shaft; then clean shaft N (Fig. 11); then put it back and adjust as described in Adjustment of Automatic Stop.
The friction clutch spring S (Fig. 11) is sometimes too weak, and should be strengthened or renewed. To take out this spring, unscrew the cap or end of shaft as shown in Fig. 11.