shallow, it is an easy matter to unscrew one leaf of each and cut a
little deeper. If they are set too deep the screws may be loosened
and a piece of paper or a shaving inserted underneath along the outer
arris of the gain.

LOCKS

The chief parts of a lock are: the _bolt_, its essential feature, the
_selvage_, the plate which appears at the edge of the door or drawer,
the _box_, which contains the mechanism including the _tumbler_,
_ward_, _spring_, etc., the key-pin, into or around which the key
is inserted, the _strike_, the plate attached opposite the selvage,
(often left out as in drawer-locks, but essential in hook-bolt locks,
and self-locking locks,) and the _escutcheon_, the plate around the
keyhole.

[Illustration: Fig. 235. Three Positions of Hinges.]

Locks may be classified: (1) According to their _uses_, of which
there are two types. (a), Fig. 236, For drawers, cupboards, tills,
wardrobes, and doors. In these the bolt simply projects at right
angles to the selvage into the strike, and resists pressure sidewise
of the lock. (b), Fig. 237, For desks, roll-top desks, chests, boxes
and sliding doors. In these, the bolt includes a hook device of some
kind to resist pressure perpendicular to the selvage. In some locks,
the hook or hooks project sidewise from the bolt, in others the bolt
engages in hooks or eyes attached to the strike.

[Illustration: Fig. 236. Rim-lock, for Drawer. 1. Bolt. 2. Selvage. 3.
Box. 4. Key-pin.]

(2) According to the _method of application_, as rim locks, which are
fastened on the surface, and mortise locks which are mortised into the
edge of a door or drawer or box.

INSERTING LOCKS

To insert a _rim-lock_, measure the distance from the selvage to the
key-pin, locate this as the center of the keyhole, and bore the hole.
If the lock has a selvage, gain out the edge of the door or drawer to
receive it. If the lock box has to be gained in, do that next, taking
care that the bolt has room to slide. Cut the keyhole to the proper
shape with a keyhole-saw or small chisel. Fasten the lock in place,
and if there is a strike or face-plate, mark its place and mortise it
in.

[Illustration: Fig. 237. Mortise-lock, for Box.]

To insert a _mortise-lock_, locate and bore the keyhole, mortise in
the box and the selvage, finish the keyhole, fasten in the lock, add
the escutcheon, locate and mortise in the strike, and screw it in
place.

WOOD FASTENINGS

REFERENCES:[*]

Ham