=96. Hand and Bevel of Doors.=—Many locks and butts used at the present time are made _reversible_; that is, they can be used for either right- or left-hand doors. Others are not, and must therefore be specified as _right-hand_ or _left-hand_. In this latter class are included loose-joint butts and most locks, the operation of which is different on one side than on the other. All locks with beveled fronts are not reversible, and their use should be avoided where no real need of them exists. A =reversible lock= is one having a beveled latch bolt that can be turned over, or reversed, at will, to make its bevel face the opposite direction. This is usually accomplished by removing the cap of the lock and turning over the latch bolt. [Illustration: FIG. 134] In order that hardware may be ordered intelligently, the _hand_ and _bevel_ of the door should be given where the hardware is not interchangeable, or reversible. Rules to determine the hand of doors have, therefore, been established by the manufacturers of hardware, so that the information may be founded on a uniform basis. Reference to Fig. 135 will materially assist in the interpretation of these rules. [Illustration: CUPBOARD AND CELL LOCKS FIG. 135] 1. The =hand= of a door is always determined from the outside. 2. The =outside= is the street side of an entrance door, the corridor side of a room door, and the room side of a closet door. The outside of a communicating door, from room to room, is the side from which, when the door is closed, the butts are not visible. The outside of a pair of twin doors is the space between them. This rule applies to sliding-doors as well as hinged doors. 3. If, on standing outside of a door, the butts are on the right, it is a _right-hand door_; if on the left, it is a _left-hand door_. 4. If, on standing outside, the door opens from you, or inwards, it takes a lock with _regular_ bevel bolt; if it opens outwards, it takes a lock with _reverse_ bevel bolt. 5. A door is =beveled= when its edge is not at a right angle with its surface, and in this case the front of a mortise lock must be beveled to correspond. This bevel is expressed by stating the thickness of door and the distance that one edge drops back of the other. The standard bevel is ⅛ inch in 2¼ inches, as shown in Fig. 136. [Illustration: FIG. 136] 6. The =bevel of a lock= is a term used both with mortise and rim locks to indicate the direction in which the bevel of the latch bolt is inclined. If inclined outwards, as for doors opening inwards, it is a _regular bevel bolt_; if inclined inwards, as for doors opening outwards, it is a _reverse bevel bolt_ (except as to cabinet locks, which, being commonly used on doors opening outwards, are regularly made with reverse bevel bolts, unless otherwise specified).