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In
addition to the mortice locks that are fitted to the front and back
door, it is advisable that a pair of bolts are also fitted to each
door. These can either be the surface mounted type, or two of which
are known as 'Rack Bolts', or Mortice Bolts. Mortice bolts are
similar to mortice locks in as much as they are fitted into the door
rather than onto it, with a hole also bored into the inside face of
the door as a keyhole. A hole will also be required in the door frame
ready to receive and hold the bolt when the door is closed, and to
make things more secure, the hole is reinforced and protected by a
metal plate that
will need to be recessed into the frame.
The ideal
position for the bolts would be about 150mm from the top, with the
other about 200mm from the bottom so as to avoid the tenons of the
door. The reason
why these bolts are important is that they compensate for the fact
that there is no locking device at these points, where the door could
be pushed in at either the top or bottom, where a bar could be inserted.
The first step
in fitting is to mark the position of the upper bolt onto the door
edge, which is approximately 150mm from the top, and by using a
square, draw a short horizontal line at this point. Then, using a
marking gauge, which has been set to half the thickness of the door,
score a vertical line crossing through the horizontal as shown in
'fig 2'. The door is now marked with the centre position where the
bolthole will be bored.
From this mark,
use a square to transfer this position to the face of the door, and
draw a second horizontal line, at the approximate position of the keyhole.
The next stage
is to bore the hole to
accommodate the bolt at the position where the two lines cross on
the door edge. This hole would normally be 16mm in diameter, and deep
enough to allow the bolt and front plate to be recessed. While
drilling, ensure that the drill is always held at 'right angles' both
vertically and horizontally to the door.
When
the bolthole has been bored out, the next step is to bore a second
hole into the inside face of the door, the keyhole. To do this, first
measure the distance from the faceplate of the bolt to the centre of
the keyhole, and using a combination square or marking gauge, draw a
vertical line at this distance from the edge of the door, so that it
crosses the horizontal line drawn previously on the inside face. |
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