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dering iron, some solder, a vial of muriatic acid. and some resin. A fairly successful job of soldering a tin dish may be done by scraping the surface bright where the hole is, sprinkling on a little finely powdered resin, laying on a bit of solder and holding the dish over a flame, which may be from an alcohol lamp, until the solder melts. It will cover the hole and stick. If the dish is rusty or badly tarnished use muriatic acid in place of resin. Resin works best when tin is bright, but usually solder sticks most successfully when the acid is used.

For soldering large breaks or doing important jobs of soldering the iron must be used. In order to work well the iron has to be kept coated with solder. When it gets blackened it should be filed until bright and then rubbed upon a smooth board while hot in a mixture of melted solder and resin. When the hot iron is taken from the fire wipe it on a damp cloth before trying to use it to lift the melted solder. A soldering iron is best heated in charcoal or the coals of a wood fire. The copper should never get red hot, as that causes the coating of the point to be burned off. soldered must always be heated will unite it.

The metal to be before the solder

Solder may be obtained in bars at any tin shop. It can be made by melting together 2 parts of lead and I of bar tin. This is the usual proportion for most purposes. Soft solder that will melt quickly and can be easily used for mending tinware can be made of pure lead and tin in equal parts. A hard solder is made by melting together 2 parts of copper to I of tin. Brazing solder is made by melting together brass and one-sixth its weight of zinc. When cool it should be granulated by pounding

with a hammer. For soldering steel and iron to brass the following combination of metal is melted together, 3 parts tin, 392 copper, and 71⁄2 zinc. Before it is applied, all the metals to be jointed together must be heated to the same temperature as the soldering alloy. Gold solder is made of 24 parts gold, 2 parts silver and I part copper. A hard silver solder is made of 4 parts silver to I of copper. A soft silver solder is made of 2 parts silver to I of brass.

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19

20

Use of the Steel Square

BY J. HAMILTON ELLIOT

N.

A steel square, often
called
a carpenter's

square, can be found in
almost any kit of me-

chanic's tools and a
little knowledge of
this instrument will
aid the user to perform
many problems easily
and quickly that other-
wise might prove dif-
ficult. Squares of dif-
ferent kinds and mate-
rials have been used by
mechanics in all ages.
The first were made of
wood and were used
in the construction of

5

the earliest buildings of which we have historic record. The squares of today are made of steel, finely polished and stamped with many

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figures, tables and rules, according to the taste of the manufacturer and the special mechanic for whom they are designed.

We will not attempt to deal with the several special kinds or makes, taking up only a few of the possibilities of the standard 2-foot square. This is 2 feet long on the blade, which is two inches wide, and it is 16 or 18 inches on the tongue or angular leg. The latter is 11⁄2 inches wide. Beginning at the heel or corner of the square, inches and fractions of inches are marked. It is necessary that the marking be in this way, in order to form the different combinations desired in connection with the different problems which have to be solved. A few of these problems are explained in the following pages.

LUMBER RULE

On the side of the blade of the square that is divided into inches and eighths is placed the lumber rule or scale. This is used for computing the number of feet in board measure contained in a given board or piece of lumber. We show a picture of a section cut from the center of the lumber rule. The space running lengthwise of the blade between the parallel lines contains the number of feet board measure for a given width of board. The first space is for boards 8 inches wide, the second for those 9 inches wide, the third for those 10 inches wide and so on. To determine the space which should be used for any given width, look under the 12-inch mark on the outside edge of the blade. These numbers give the width of the board, also the number of feet board measure. If a board is 10 inches wide and 12 feet long, it contains 10 feet board measure.

Now let it be required to find the number of feet board measure in a board 13 inches wide and II feet long. Find the space for boards 13 inches wide under the 12-inch mark on the square, follow this space to the left and under the II-inch mark on the square will be found the answer desired: II-II. This is read II feet and 11/12, and is the number of feet board measure contained in a board

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13 inches wide and 11 feet long. With a little practice, anyone can measure lumber or timber and check up his bills for this kind of material.

Do not confound foot board measure with square feet. Square feet are in surface measure, with no reference to thickness, while a foot board measure is the equivalent of a foot square and I inch in thickness. The square feet of a 3-inch plank would contain 3 feet board measure.

After becoming familiar with the use of the lumber rule, as described above, you will discover that the space may be taken to contain the amounts for a given width and the different lengths in feet as represented in the different columns, or the space may be taken as containing the amounts for a

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