t strength is desired. There are
three chief varieties, Fig. 230.

[Illustration: Fig. 230. a. Stove-bolt. b. Carriage-bolt. c.
Machine-bolt.]

_Stove-bolts_ are cheaply made (cast) bolts having either flat or
round heads with a slot for the screwdriver, like ordinary screws.

_Carriage-bolts_ are distinguished by having the part of the shank
which is near the head, square.

_Machine-bolts_ have square, hexagonal, or button heads.

_Machine-screws_, Fig. 231, are similar to stove-bolts, but are
accurately cut and are measured with a screw-gage. The varieties
are, _a_, flat-head, _b_, round-head, _c_, fillister-head, _d_,
oval-countersunk-head, all with slots for screwdriver.

_Plates_, Fig. 232, include corner-irons, straight plates and
panel-irons. These are made of either iron or brass and are used in
fastening legs to the floor, in stiffening joints, affixing tops, etc.

_Dowel-rods._ Dowel-rods are cylindrical rods, from 3/16" to 1" in
diameter, and 36", 42", and 48" long. They are commonly made of birch
or maple, but maple is more satisfactory as it shrinks less and is
stronger than birch.

Dowels are used as pins for joining boards edge to edge, and as a
substitute for mortise-and-tenon joints.

[Illustration: Fig. 231. Machine-screws. a. Flat-head. b. Round-head.
c. Fillister-head. d. Oval-countersunk-head.]

There is, to be sure, a prejudice against dowels on the part of
cabinet-makers due, possibly, to the willingness to have it appear
that doweling is a device of inferior mechanics. But doweling is
cheaper and quicker than tenoning, and there are many places in wood
construction where it is just as satisfactory and, if properly done,
just as strong. Certain parts of even the best furniture are so put
together.

Shoe pegs serve well as small dowels. They are dipped in glue and
driven into brad-awl holes.

[Illustration: Fig. 232. a. Corner-iron. b. Straight plate. c.
Panel-iron.]

_Wedges_ are commonly used in door construction between the edges of
tenons and the insides of mortises which are slightly beveled, No. 34,
Fig. 266, p. 179. Or the end of a tenon may be split to receive the
wedges, No. 35, Fig. 266. The blind wedge is used in the fox-tail
joint, No. 36, Fig. 266.

GLUE

Glue is an inferior kind of gelatin, and is of two kinds,--animal glue
and fish glue. Animal glue is made of bones and trimmings, cuttings
and fleshings from hides and skins of animals. Sinews, feet, tails,
sno