=8. Wood Screws.=—The ordinary =wood screw=, which is one of the staple
articles of hardware, is very necessary in the application of all
builders’ hardware about the building. Except in some lines of cheap
or rough, unfinished goods, hardware manufacturers now pack with all
hardware, screws that match the finish of the goods. The various types
of screws now on the market are illustrated in Fig. 5, and the common
types, such as flat-, round-, oval-, and fillister-headed screws are
easily procured.
Iron screws are made with either flat, round, or oval heads and the
following finishes: Bright, blued, japanned, tinned, galvanized,
bronze-plated, brass-plated, coppered, silvered, and nickel-plated.
Brass and bronze metal screws can also be procured with flat, round, or
oval heads, in either natural color or, on special order, finished to
match the hardware. Special screws are also manufactured for various
purposes, which are sufficiently explained by the illustration, Fig. 5.
[Illustration: FIG. 5]
Screws are always measured for length from the point to the top of the
head. The sizes in which screws can be obtained are given in Table IV.
The diameter of screws is always measured directly under the head, and
is always given in numbers of the screw makers’ gauge. The numbers
vary from 0 to 30, going consecutively without skip from 0 to 18
and from then on using only the even numbers. In Table IV are also
given the numbers of the screw makers’ gauge and their equivalents in
decimals of an inch.