Deadbolt Locks Explained


Deadbolts for Home Safety

One of the most easy ways to increase the security of your home is by installing a deadbolt on the front door. A deadbolt is an additional lock that can be installed relatively easy. The principle is simple: when in locked position, a bar of steel or iron is pushed against the doorframe or wall to prevent the door from moving. When you twist the lock the position of said bolt moves back into the door (open position) to allow access. If you do not have a quality deadbolt, it is easier for thieves to break into your home by force (kicking the door). You can have either a basic deadbolt lock or an upgraded one with more security measures. Deadbolt locks are available in different quality en security levels: ANSI grade, UL listing, and double or single cylinder locks.


Deadbolt Locks Explained


Single cylinder

A single cylinder lock only has one slot for the key. You will need a key to open it from the outside, but it can be opened at any time and by anyone from the inside by turning the knob. The single cylinder deadbolt should not be used for doors nearby windows: burglars can break the glass and simply turn the deadbolt from the inside.  These locks are an excellent additional security precaution for back and frontdoors closed in by walls.

Double cylinder

A door with double cylinder lock provides more security than the single cylinder one. One cannot enter or exit it without a key. The deadbolt can only be trown or retracted by key from both the inside as well as from the outside. These work best for the front door of a house or an office room with (breakable) windows near the door. Make sure to store a key out of reach for burglars, but close enough for yourself incase you have to escape from the house in an emergency or  firehazard.


Security Grades

The United States Standards Institute – a non-profit organization called ANSI (American National Standards Institute) – grades the quality, longevity, toughness, and durability and latch lenght of locks. Deadbolt lock grades are divided into 3 categories: grade 1, the strongest, most secure deadbolt lock;  grade 2, the second highest security lock, most commonly used in residential buildings or shops; and grade 3, which is the minimum grade. If you want maximum residential security, use a grade 1 lock.


Underwriter Laboratories, provides a lock security rating called UL437. It rates all keyed locks including the deadbolts that we discuss in this post.
The Underwriter Laboratories deadbolt security test is one of the hardest to pass; it tests against  forcing, drilling, sawing, prying, picking, impressioning and bumping as well as an endurance test that tests the ability to withstand 10000 cycles of opening and closing the lock.


 Other things to Consider

More often than not, a deadbolt fails to do its job when your door gets kicked down. To prevent forced entry like that, you should use a high quality strike plate. As mentioned previously, a bolt, when in ‘close’ position, should extend into the doorframe. The hole in the doorframe should be enforced with solid strike plates made of metal and secured to the wall with 3 or 4 inch screws.
Most deadbolt locks come with a strikeplate, however in most cases it proves to be to flimsy and not solid enough. The Assa M80 comes with a decent strikeplate and is the deadbolt lock that i recommend.

 Most locks cannot withstand a drill

Even  deadbolts graded as “high security locks” cannot withstand an ordinary cordless drill. Most deadbolts can be opened in less then 2 minutes with a drill.  Medeco and Assa provide the best security against drilling; drilling will ruin these locks but they mostly will not open just like that.


You get what you pay for

Like with most things in life, you do get what you pay for, so when purchasing new locks you should consider what’s most important to you: the safety and security of your family, or the amount left in your wallet. I always advise to buy a high quality deadbolt in combination with a high security cylinder, these will last forever and can save you a lot of trouble. Medeco offers good quality deadbolts for around $140 Dollars.


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