(14) In filing work press down on the outward or cutting stroke and ease up on the file on the return stroke for the teeth of a file are set like the teeth of a saw, that is, so that the cut is made on the out stroke.
A small file can be held in one hand and the work you are filing in the other which can be rested on the edge of the bench but heavier work must be put in a vise and the file held firmly by the handle with one hand and the end steadied and guided by the fingers of your other hand.
(15) In putting in a screw always use the largest size screw-driver whose blade will fit the slot in the head of the screw; this will prevent the blade of the screw-driver from twisting the edges of the slot out of shape.
(16) Before a soldering copper can be used, if it is a new one, it must be tinned, that is the point of it must be coated with solder. To tin it get a pine board about 1 inch thick, 4 inches wide and 6 inches long, and put some brown resin and bits of solder on it.
File off the copper until the point is sharp and it is bright and smooth; heat the copper and then melt the resin and solder on the board with it and rub the copper in them on all sides until a film of solder is formed on it.
(17) It is cheaper to buy a stick of soldering paste than it is to make it but you can easily and cheaply make a good soldering fluid by dissolving a teaspoonful of zinc chloride in an ink bottle full of clean water.
In heating the soldering iron keep it near the tip of the flame; if you use an alcohol lamp don’t have the wick too high and if you use a Bunsen burner adjust the openings in it until the flame is as nearly invisible as you can get it.
About Sharpening Tools.
—The only metal working tools you will need to sharpen are the twist drills and these can be sharpened on a carborundum oil stone. Hold the beveled edge of the drill point on the stone and move it to and fro, being very careful to keep the drill perfectly straight up and down while you are sharpening it.