Many home workers have fitted night latches successfully, but others have not been so fortunate in their attempts. A few suggestions which do not usually appear in the printed instructions accompanying the locks may be of help in simplifying the work.

We shall consider first the fitting of a rim spring latch of the standard type in the usual way for a right- or left-hand door (Fig. 43). Locate the desired height of the latch, about 3 ft. 6 in. from the floor but somewhat less if the approach is from a porch floor that is lower than the floor of the house. If the distance from the center of the cylinder to the edge of the door is supposed to be 2 in., it is well to mark it actually 21/16 i8n, so as to set the latch back 1/16 in.; this allowance is for planing, should the door stick at any time. Bore a 1-in. hole entirely through the door stile.

Fig. 43. - A standard night latch can be fitted in two ways, depending on whether the door is one opening in or out.

Break the connecting bar and the screws as indicated on them to suit the thickness of the door. Slip the cylinder through the outside ring until the back of the face is seated. Insert the cylinder from the outside of the door with the keyhole down. Place the false cap or perforated plate on the lock side with the screw holes above the center. Drive home the two connecting screws that fasten the false cap, the cylinder, and the face ring firmly in place. Locate the latch accurately and drive the screws which hold it in place on the door.

To apply the striker - the member which is engaged by the latch - it may be necessary in certain cases to cut into the door casing as at A, as well as into the edge of the door jamb.

In fitting a night latch on a door opening out, the lock must be set back far enough from the edge of the door to clear the corner of the rabbet at B. We shall assume that the rabbet is ½ in., which, in the case of a close-fitting door, will require that the cylinder center should be set back about 2 9/16 in. This must be verified in every case. Bore the 1-in. hole, remove the backplate of the latch, reverse the latch itself, replace the backplate, and proceed as previously described.

A reverse bevel striker must be fitted to the rabbet so that the latch will engage. The striker should be set in a notch cut into the jamb to receive it as illustrated.

When locks and other hardware are of unusual design, the manufacturers supply full instructions for fitting them.