Square a line across the top edge in the middle, and square it down the front for a short way. Set a gauge to the pin of the lock and mark the centre line. With a bit of the same size as the rounded top part of the escutcheon bore a hole right through the front where the lines intersect. Place the escutcheon on the hole, see that it is square, and tap with a hammer to make a light indentation. Cut down the lines with the key hole saw, the latter on the waste side, and remove the waste with a small chisel. Tap home the escutcheon, making it a fairly tight fit.
Place the lock at the edge so that the pin coincides with the pencil line, and mark on the edge the position of the body of the lock. Gauge in the depth and width, and cut in the sides as far as the saw can be taken. Make two or three extra cuts between to cut up the grain. Chisel away the waste chopping down the sides where necessary. Place the lock in position and mark where the back plate comes. The lines across the grain can be cut in with the knife and square, but those along the grain are best gauged in. Since the already cut recess makes this awkward it is helpful to place a thin strip of wood of even thickness along the inside of the drawer front as shown by the dotted lines at F and use the gauge over this. Chop down around the outline, and pare away the waste. The recess is thus formed. Screw on the lock and cut the slot in the rail into which the bolt slides. To find the position of this, open the drawer and turn the bolt.
- Straight cupboard lock.
- Sliding door lock.
Mortise lock and how it is recessed into edge of door. A marking position of keyhole. Distance of pin from edge is gauged in; B mortise position is found by holding lock with pin level with keyhole.
the centre of the pin allow it full 1-2mm so that the edge of the main plate stands In. Bore and cut the keyhole and, holding the lock in place, mark the extent of the recess. A gauge can be used to mark the sides. The recess can be partly bored then chopped with the chisel, the router being used to finish off. Note that spaces into which the bolt can shoot are necessary.
Screw on the lock, insert the plate and turn the key. If the door is then closed the position for the plate on the cupboard can be noted. As a rule it lines up with the main plate of the lock so that the position is obvious; however it is advisable to check this.
As the name suggests, the mortise lock fits in a mortise or recess in the edge of the wood. Its advantage is that it is not so easily forced as cut and straight locks. Either of the latter would give under pressure since the screws would simply be forced out. Square the keyhole position on edge and face, set a gauge to the pin centre, and mark. Bore the hole through to about the middle of the wood only, not right through. Cut in the rest of the hole. Hold the lock level with the squared line and mark the ends of the body of the lock. A mortise gauge can conveniently be used to mark the sides. Much of the waste can be bored away, the rest being chopped. If the lock is then dropped in the plate can be marked round. The sides of the lock should bear against the wood and should not be a loose fit, otherwise the entire strain is taken by the fixing screws.
Box locks. Box locks can be of either the cut or the mortise type, and the marking and cutting is as already described. The only extra operation is that of fixing the plate to the lid. Put the plate so that it engages the lock, close the lid, and give the latter a thump locally. This will force the spikes on the plate into the wood so that the plate lifts with the lid. This fixes its position.
There are many other special types of locks, but the principle of fitting is founded on the main types given.