Sound locking devices cannot make a residence completely impregnable, but they can deter a burglar. They can force him into a situation in which he must break glass in order to enter—something he would probably like to avoid.
The amount of money spent on security hardware should be proportional to what is being protected. But by the same token, purchasing security hardware which meets the minimal technical requirements listed below could also protect your family from bodily injury. Since prices for security hardware vary depending on the area, the manufacturer and differences in cosmetic features, the buyer should "shop around."
A chain latch on your door offers no security at all. Chain latches can be easily ripped off the door with minimum pressure. The best way to check a caller's identity is to use a wide angle viewer or peephole.
Types of Locks
A common type of lock in many homes and apartments is the key-in-knob or spring latch type. This particular lock is easily defeated by the most amateur burglar with a credit card or screwdriver inserted between the latch and the strike plate. This lock offers no security and should be supplemented by a single or double cylinder deadbolt lock or rim type or surface mounted lock. The dead latch is similar to the spring latch lock but has a small bar or plunger
which will not permit opening with a shimming device. This is a poor security device since the plunger is very short and weak and should be supplemented by a quality deadbolt lock.
A single cylinder deadbolt lock should be mounted on a solid wood core door when there is no breakable glass within 40 inches of the interior locking mechanism. The single cylinder deadbolt lock has a thumb turn piece on the inside
A double cylinder deadbolt lock, which is keyed operated from both the interior and exterior, should be used when there is glass within 40 inches of the interior locking mechanism. (Caution: The use of a double cylinder deadbolt lock can be a fire escape hazard. If this type of lock is used while the home is occupied, either leave a key in the lock or hanging somewhere near the lock. Children should be trained in the use of this lock and know the exact location of the key. When the dwelling is unattended, the key should be hanging out of the reach of a burglar who mav break the glass.)
When moving into a new dwelling, have tumblers in all exterior locks changed. This can be done inexpensively by a licensed locksmith. Or, if you are reasonably handy, you may wish to change all exterior locks yourself.
Both single and double cylinder deadbolt locks should meet these basic criteria to be a good security device:
The bolt must extend a minimum of 1 inch and be case hardened or contain a hardened insert.
The cylinder guard must be tapered or spherical in design to make it difficult to grip with pliers or a wrench. It must be made of solid metal—not a hollow casting or stamped metal—and preferably be able to turn freely.
The connecting screws that hold the lock together must both be on the inside. There must be no exposed screw heads on the exterior of the door.
The connecting screws must be at least 4 inch in diameter and screw into solid metal stock—not screw posts.
When shopping for a deadbolt lock, you may wish to take the above diagram and description to a locksmith or hardware store to be sure the lock you buy meets all of the requirements.
Padlocks should be of case hardened steel construction with a minimum 9/32 inch shackle. The lock should have a double locking mechanism on both the heel and toe of the shackle. It should be of heavy body construction with a minimum five pin tumbler.
The bottom end of the padlock may have a key number stamped on it. This number should be obliterated and recorded else-where to eliminate the possibility of unauthorized key duplication.
The hasp should be as strong as the lock and have no screws or bolts visible when secured. Screws which hold the hasp in place should be as long as the material holding them will allow. If installed on metal, carriage bolts with large washer should be used to prevent prying of the hasp.
Rim Type or Surface Locks (Jimmy Resistant)
Rim type or surface locks use a vertical or horizontal deadbolt locking mechanism (see diagram). These locks are mounted on the interior surface of the door. A rim type lock is good security if it is the interlocking (jimmy resistant) type. With proper strike, an interlocking rim lock can be used on either in-swinging or out-swinging doors.
Proper installation of this lock is extremely important. The strike should be secured to the door jamb with minimum 2 inch wood screws. The lock must be through-bolted to the door with carriage bolts. Do not use wood screws to mount the lock.
Do not allow children to open the door to strangers!
As a second line of defense, you may want to consider a security closet for storage of valuables which are kept in the home. This closet should be equipped with a solid wood core door with hinges with non-removable pins and a good quality deadbolt lock.
Crime Prevention Guide