Find out which door locks the thieves
like, which are easy to break through and which will keep your home
door knob lock. Photo courtesy Masterlock
Standard Door Knob Locks
Every exterior door should have a knob lock with a bolt that extends
from the door knob into the door frames strike plate. The strike plate
is mounted into or onto the door frame. Door knob locks are usually
selected by the homes builder or contractor. Contractors are of course
not "lock experts" and the selection is often based on price. The
homeowner can make a much better selection knowing what features to look
for and what options are available. In addition, all exterior doors
should have a deadbolt. Deadbolts are available as separate units or can
be incorporated in a combination with the door knob lock.
The American National Standards Institute (ANSI) has requirements,
developed and maintained by The Builders Hardware Manufacturers
Association (BHMA). When replacing exterior door locks, use ANSI Grade 1
For convenience, knob locks can be matched to open with the same key as
dead bolts and locks on other exterior doors, eliminating the need to
carry and keep track of multiple entry keys. Knob locks are also
available with combination locks.
Dead Bolt lock. Photo courtesy Masterlock.
Dead bolts should extend further into the strike plate than a standard
knob bolt. At least 1" is recommended. Longer throws makes it more
difficult to gain entry by spreading the doorframe. Standard deadbolts
utilize a key to open the lock when entering from outside and open from
the inside with a single action turn of a knob, thus preventing any
entrapment in the event of an emergency. Burglars, however, can easily
gain entry through a locked door, even with a dead bolt, by breaking the
glass in a window, reaching in, and simply unlocking the door. Standard
deadbolts are therefore only recommended for all solid exterior doors
without any glass or mail slots within 36” of the lock. If glass panels
must be closer, deadbolts can still be used if the glass is covered with
a security film, which prevents breakage.
Cylinder Dead Bolt lock. Courtesy Rhodes Lock and Key
Double Cylinder Deadbolt
Homeowners, in an effort to prevent the above listed type of entry,
install what's called a “double cylinder deadbolt”. This uses a key on
both sides of the door. Unfortunately, when the interior key is not in
place the double cylinder deadbolts do not allow quick escape during an
emergency. If the internal key is left in place the lock basically
functions as a standard deadbolt and provides no additional security.
Captured Key Dead
Bolt lock. Photo courtesy MUL-T-LOCK-Online.com
Captured Key Deadbolt
This type of lock is much like a combination between a standard deadbolt
and a double cylinder deadbolt. A captured key deadbolt is advertised as
a way to prevent a thief from breaking glass within arms reach of the
lock and, reaching in to unlock a door while still providing a safe and
quick escape for the family during an emergency. On the interior side of
the door the deadbolt lock has a thumb turn which can be removed from
the lock, leaving only a keyhole. The idea is when no one is home, there
is no need to leave the thumb-turn in place. The last person to leave
removes the thumb-turn and basically creates a double cylinder deadbolt.
This way thieves could not reach in to open the latch. The thumb-turn
cannot be removed without having a key to the lock. Therefore, small
children cannot remove the thumb-turn key. The thumb-turn can also be
used as a house key. It is important that whenever anyone is in the home
that the thumb-turn is left in the lock at all times. Otherwise, there
will be no escape during a fire or other emergency. In evaluating this
type of lock it should be considered that the same results can be
obtained with a double sided deadbolt by just leaving the key in place
when at home. The problem arises when wanting security while you or your
children are at home. In this day and age why would anyone want a
criminal to be able to reach in and open a door or have to rely on
everyone in the household to remember to leave the interior key in place
to be assured a quick exit in an emergency. In my opinion, their are too
many things that can go wrong with either the double sided or captured
key deadbolt to make either worthwhile.
Dead Bolt lock. Photo courtesy Masterlock.
Many rim latch style deadbolts lock automatically when the door is
closed. These are great and offer the additional security of not having
to remember to always lock your door. The only problem is you can easily
get locked out.
Fairly new on the market, these locks are an excellent choice and there
is no need to worry about losing keys. A simple code opens the lock.
This code can be changed from time to time or whenever the code is no
longer maintained as a secret. i.e. when household help is terminated.
Keyless locks are available on door knob locks, deadbolts and
combination deadbolt knob lock sets.
Dead Bolt lock. Photo courtesy Sunneo Biometric Co.
One step above the keyless lock is the fingerprint controlled lock set.
Again a great system with no keys to misplace. The main advantage to a
fingerprint door lock system is its convenience. These systems are
battery powered and come with a low-battery indicator. This system, as
well as the keyless lock, are available with an excellent assortment of
security features that make them as secure as a deadbolt but a lot more
Key control is simply a way of controlling who has copies of keys to the
home. There are many burglaries where the entry can be traced back to a
key that was somehow obtained by the burglar. Most door keys can be
easily copied at any local hardware store. Manufacturers now offer locks
that use keys that cannot be copied except by locksmiths or the
Key control locks are more expensive and require some extra effort from
the home owner. For example, an additional cost is involved in order to
get any replacement keys made. The cost and inconvenience of having to
go to a locksmith rather than the local hardware store, is weighed
against the added security benefits. Key control locks are available in
all style deadbolt locks.
Some deadbolts come with an internal anti-saw pin. The pin spins freely
inside the bolt. When a thief tries to saw through a deadbolt with a
hacksaw, the pin spins back and forth with every movement of the saw.
This system is not fool proof but makes it more time consuming for a
burglar to cut through a lock bolt.
Hardened Cased Steel & Beveled Casings
The outside housing of a lock is called the "casing". Many lock
manufacturers make their casings out of hardened steel and many make the
casing beveled. The hardened cased steel makes the casing more resilient
against impact blows. Beveling the casing makes It difficult to keep a
wrench on the lock if a thief attempts to twist the lock free with a
Some determined thieves will actually take the time to drill out a lock.
Manufacturers combat this by installing hardened steel chips within the
lock. When a drill bit hits these hardened steel chips, the drill bit is
Remember, the intruder will select the door that looks easiest to break
into and that offers the least chance of being seen. Back doors and
Garage doors leading into the house offer an intruder privacy and the
ability to safely spend extra time breaking in. Extra thought should go
into the security at these locations.
Selecting the right door locks and knowing where to install them is only
part of a good security plan for your home. When considering security on
exterior doors, the strength of the door and doorframe are just as
important as the strength of the door lock.
Guide to Home Security, by Dan Berg, Your complete guide to
locks, alarms, cameras and security systems designed to protect
homeowners and their valuables. This book is available as an inexpensive instant-download
that you can print today and read again and again
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