A very handy way of marking polished steel for sizes, instructions, etc., is to keep a small oil can filled with turpentine with which to saturate a small piece of waste as needed; rub over the surface to be marked and then do the marking with an indelible copying pencil, which will show up very plain. Of course the can of turpentine also comes in handy to use for drilling hard steel, springs, etc.
St. Paul, Minn. Arthur Munch.
To find out whether a piece is steel or iron touch it with nitric acid, using a stick of wood, and then wash it with water. If iron, a light or azure stain will appear. if steel, the stain will be black.
Los Angeles, Cal. J. M. Menegus.
A simple acid test for iron and steel is made as follows: The sample to be tested should be filed smooth or polished. Then place it in dilute nitric or sulphuric acid for from 15 to 20 hours; then wash and dry the sample. The best steel then has a frosty appearance, ordinary steel has a honeycombed appearance; and iron presents a fibrous structure in the direction in which it has been worked. A. A.
Before pouring the babbitt metal, throw in a piece of rosin,the size of a walnut and allow it to melt. If the bearings to be lined with babbitt are warmed before pouring, the metal will run better, thus insuring a better job. R. B. Casey.
Sohenectady, N. Y
To make an anti-leak and lubricating mixture for plug cocks use 2 parts of tried suet and 1 part of beeswax melted together; stir thoroughly, strain and cool.
A mixture for making glass stoppers tight is made by melting together equal parts of glycerine and paraffin. L. S. Burbank.
To keep steel tools in their handles, fill the handle with powdered rosin and a little rotten stone. Heat the tang of the tool hot, and then push it down hard into the handle; when it is cold it will be firmly set. M. E. Howe.
An excellent strop paste for edging razors or other keen-edge tools is a mixture of levigated oxide of tin, 1 ounce. powdered oxalic acid, ¼ ounce; powdered gum, 20 grains. Mix to a paste with water, spread evenly over, and work well into the strop with some smooth surface. The rough side of the strop gives best results.
Denver, Col. B. W. Bowen.
A hole may be cut or etched through glass readily by using hydrofluoric acid. The acid should be applied in the same way as etching acid, using wax to surround the portion of the glass which is to be penetrated. Hydrofluoric acid is sold in wax bottles. as it cannot be kept in glass. It may be handled with a hard rubber dropper similar in construction to the ordinary glass medicine droppers. S. W. Green.