The Crime Prevention Website


Mortice security bolts

These bolts are sometimes referred to as mortice rack bolts and as the name suggests they are fitted into a cylindrical mortice that has been drilled into the door leaf.  They are normally fitted to timber doors that have mortice sashlocks, such as French doors and the back door.  The bolt is operated using a common splined key on the inside of the door, although some models provide a key cylinder option.  The advantage of this type of bolt is that you only see the keyhole and not the bolt.  It is also generally accepted that if the door is around 44mm thick or more then a mortice lock will be stronger than a surface mounted bolt.  These bolts are best fitted at 90° to the grain of the timber to reduce the possibility of splitting and so they are normally fitted into the latch stile of a single leaf door and the top and bottom rails of a double leaf door.  If you are likely to use this door in an emergency then it is probably not a good idea to use these bolts at night. 

Press bolts

These are surface fitting bolts often used in place of mortice security bolts.  They are ‘pressed’ into place and a key is used to unlock them.  They are not suitable for use on doors used as a means of escape in an emergency. 

Barrel bolts

Surface mounted barrel bolts are still seen used on some very large Victorian and Georgian doors and are used by people to provide some additional night time security.  They are available in a vast range of styles and sizes and you can still get very large ones up to 250mm in length.  Barrel bolts are not suitable for use on a designated emergency exit door or on a door that provides your only means of escape.  This is because there is a danger of them sticking (timber doors swell and shrink with the seasons) making them difficult to withdraw and young children may not be able to reach them or have the strength to operate them.  If you live in a single family occupied house then it’s really up to you whether you use them or not, but please make sure that they are maintained and are easy to use by all members of the family.  When you fit these bolts make sure you use the longest and largest gauge screws that are practical for the fitting and door leaf. 

Hinge bolts


Hinge bolt


These are fit and forget steel pins, sometimes called dog bolts that are fitted into the hinge side of a door leaf.  As you close the door the pin, or bolt passes into a keep in the door frame.  These bolts are fitted in pairs with one about 150mm below the top door hinge and the second about 150mm above the bottom hinge.  They should be fitted to all outward opening timber doors where the hinges are exposed and to inward opening doors that might be susceptible to kicking and barging, such as a recessed front door and a private flat entrance door.

True story

In 1984 I locked myself out of my house.  It was a brand new house built by a national house builder who shall remain nameless.  Having attempted and failed to open the front door through the letter plate I went round the back and examined the back door and windows.  To my delight (and horror) I noticed that the hinges on the back door were fitted with dome headed hinge pins that I could remove with my fingers.  As my neighbour held the door I took out the three hinge pins and gently levered the door out from the door frame.  It took me about five minutes and no damage was caused.  Once I had got in I just repositioned the door and popped the pins back in.  Later, of course, I fitted a pair of hinge bolts and gave my neighbour a set of keys in case of future emergencies. Why didn’t the builders consider this?