The Boy Mechanic: Volume 1 | Page 8

toothpick or splinter of wood
and tying the hanging string to it.
[Illustration: Repaired Decoration]

** Homemade Scroll Saw [11]
A scroll saw, if once used, becomes indispensable in any home
carpenter chest, yet it is safe to say that not one in ten contains it. A
scroll saw is much more useful than a keyhole saw for sawing small
and irregular holes, and many fancy knick-knacks, such as brackets,
bookracks and shelves can be made with one.
A simple yet serviceable scroll saw frame can be made from a piece of
cold-rolled steel rod, 3/32 or 1/4 in. in diameter, two 1/8-in. machine
screws, four washers and four square nuts. The rod should be 36 or 38
in. long, bent as shown in Fig. 1. Place one washer on each screw and
put the screws through the eyelets, AA, then place other washers on
and fasten in place by screwing one nut on each screw, clamping the
washers against the frame as tightly as possible. The saw, which can be
purchased at a local hardware store, is fastened between the clamping
nut and another nut as shown in Fig. 2.
[Illustration: Frame Made of a Rod]
If two wing nuts having the same number and size of threads are
available, use them in place of the outside nuts. They are easier to turn
when inserting a saw blade in a hole or when removing broken blades.
--Contributed by W. A. Scranton, Detroit, Michigan.

** How to Make a Watch Fob [12]
The fixtures for the watch fob shown--half size--may be made of either
brass, copper, or silver. Silver is the most desirable but, of course, the

most expensive. The buckle is to be purchased. The connection is to be
of leather of a color to harmonize with that of the fixtures. The body of
the fob may be of leather of suitable color or of silk. Of the leathers,
green and browns are the most popular, though almost any color may
be obtained.
Make full size drawings of the outline and design of the fixtures. With
carbon paper trace these on the metal. Pierce the metal of the parts that
are to be removed with a small hand drill to make a place for the leather
or silk. With a small metal saw cut out these parts and smooth up the
edges, rounding them slightly so they will not cut the leather or silk.
Next cut out the outlines with the metal shears. File these edges,
rounding and smoothing with emery paper. The best way of handling
the decorative design is to etch it and, if copper or brass, treat it with
color.
For etching, first cover the metal with black asphaltum varnish, on the
back and all the parts that are not to be touched with the acid. In the
design shown, the unshaded parts should not be etched and should,
therefore, be covered the same as the back. Apply two coats, allowing
each time to dry, after which immerse the metal in a solution prepared
as follows: 3 parts water, 1 part nitric acid, 1 part sulphuric acid. Allow
the metal to remain in this until the acid has eaten to a depth of 1/32 in.,
then remove it and clean in a turpentine bath, using a swab and an old
stiff brush. The amount of time required to do the etching will depend
upon the strength of the liquid, as well as the depth of etching desired.
[Illustration: Watch Fob]
For coloring silver, as well as brass and copper, cover the metal with a
solution of the following: 1/2 pt. of water in which dissolve, after
breaking up, five cents worth of sulphureted potassium. Put a
teaspoonful of this into a tin with 2 qt. of water. Polish a piece of scrap
metal and dip it in the solution. If it colors the metal red, it has the
correct strength. Drying will cause this to change to purple. Rub off the
highlights, leaving them the natural color of the metal and apply a coat
of banana-oil lacquer.

** An Austrian Top [12]
All parts of the top are of wood and they are simple to make. The
handle is a piece of pine, 5-1/4 in. long, 1-1/4 in. wide and 3/4 in. thick.
A handle, 3/4 in. in diameter, is formed on one end, allowing only
1-1/4 in. of the other end to remain rectangular in shape. Bore a 3/4-in.
hole in this end for the top. A 1/16-in. hole is bored in the edge to enter
the large hole as shown. The top can be cut from a broom handle or a
round stick of hardwood.
[Illustration: Parts of the Top]
To spin the top, take a piece of stout cord about 2 ft. long,