Door Lock Replacement, Adjustment and Repairs
Discover your hidden locksmithing talents!
The Basics of removing and replacing residential
First things first! I have found that certain locks were designed to be virtually impossible to
take apart by anyone other than a locksmith. They require special screwdrivers,
pins, or wrenches, difficult or impossible to purchase at your local hardware
store. Some locks come with these special tools, but are either lost by the
homeowner or "unintentionally" taken by the installer to assure future
business. I have had the pleasure of cutting off the knobs on more than one
lockset in my day. What amazes me is that, on some of these locks, even after I
had it cut off, I still couldn't figure out how to disassemble it!! A testament
to the ingenuity and creativity of a fine designer!
Fortunately, most home locksets made in the last 20 years are user-friendly,
most requiring nothing more than a screwdriver or two to disassemble them.
Lock types revealed!!
The most common styles of residential entry locks today are the tubular or cylindrical lock (graphic left). For purposes of installation or replacement they
are similar and you can't really tell the difference between these locks without
actually removing the lockset from the door. In fact, if you were to go to the
hardware or home store to purchase a lock, chances are there is no indication on
the packaging whether the lock is cylindrical or tubular. In function the cylindrical lock is
a sturdier beast and is, of course, the more expensive of the two.
In the olden days... after dinosaurs but before television... many residences
used mortise locks
(graphic right) A combination deadbolt
and spring-type latch, it was installed into a mortise or deep rectangular
groove in the edge of the door. The mortise lock is much more time consuming to
install and more expensive to manufacture, but one of the strongest styles of
lock. Due to cost considerations, it is not used frequently in modern homes.
However, it is still available as a "high end" (read mucho expensive)
product. Mortise locks are still commonly used in high security business
The other lock commonly used on exterior doors is the deadbolt
Deadbolts utilize a latch which is designed to move deep into the door jamb by
turning a key, lever, or knob. The deadbolt is meant to back up the relatively
low security of an entry lock. The weak link in most locksets is not the lock
itself but the door, the door jamb, and strike plate that the latch sets into.
That's why many deadbolt manufacturers supply specially reinforced strike plates
with long screws to secure it to the door frame.
You can also purchase double-cylinder
deadbolts. No, they aren't twice as strong!
Double-cylinder means that a key is required to open the deadbolt on both the
inside AND the outside. These are commonly used on doors that may allow
access to the inside handle, such as doors with glass windows.
Disassembly of your existing lockset...
Remove all visible screws. Sometimes, this is all it takes. Medium to low
cost locksets are basically sandwiches, with the inside and outside handles
screwed together. If there are no
visible screws, it means that the lock is being sneaky and must be punished!
Certain brands of entry locks conceal the screws under the rose... the circular,
decorative cover that presses against the door when the lock is assembled. With
this style of lockset, the interior door knob must be removed first. Then the
rose can be removed by prying it away from the door with the gentle use of a
flat blade screwdriver, exposing the screws.
Examine the doorknob carefully. Are there any openings or slots that could
accommodate a pin, awl, or flat blade screwdriver? Some locks incorporate a
spring catch that can be depressed with one of these tools, allowing you to
remove the knob. Many locksets of this type have the removable knob on
the inside, for security reasons.
Look at the latch. Are there any holes or openings in it that would allow a
tool to be inserted? Some locks are held together by a screw, usually with an
Allen head, that is set inches into the door. This screw attaches the latch to
the cylinder of the lock, making the lock impossible to disassemble if the door
is closed. The problem here is that standard Allen wrenches are not long enough
to reach this screw, and you will probably have to go to a local locksmith to
Deadbolts sometimes have metal screw covers installed over the screw heads,
to discourage casual removal. These covers can be removed by prying with a thin
screwdriver or pulled out using locking pliers. Other deadbolts have internal
covers that close over the screw heads when the latch is extended. By turning
the key inwards, the screw covers retract to reveal the screw heads.
If after all this, you still can't figure the lock out, and you feel like
your back is against a wall, do what NH does...go to the shop of a local
locksmith and ask him!
Locksmiths are in business to make money. And it is true that, most of the
time, the products they sell will cost a little more than similar products at
the big home improvement stores. As a handyman in your own right, you will find
it worthwhile to get acquainted with and shop at the specialty stores in your
area. These people have worked hard for years to develop their skills and
knowledge and have much to offer you.
What I am saying is, if this person can help you out of a tight spot, you at
least owe him a sale! I don't think there is anything sleazier than people who
will gladly take all of your time for free, but shop elsewhere!
If you choose not to shop locally, the local shop will go out of business.!!
Sometimes, the new lock you purchased won't fit into
the old hole. Rats!! What's best way to enlarge the hole?
If the old hole through the door is 2 1/8" or more, there are many entry
locks that will accommodate the existing hole, such as a Schlage. I will walk
you through the enlarging of the hole, and when I'm through, I won't think less
of you if you pack up that lock you just bought and exchange it for one you can
install in the existing hole!
Barring the rental or purchase of a special locksmithing jig, proceed as
- Get a piece of minimum 1/2" thick wood or plywood that is at least
6" wide by 8" long.
- Position the new lockset's template (the guide for drilling that came
packed with your new lock) on the piece of wood as if it were the face of
the door. Mark the center of the hole and remove the template. Be sure you
use the same backset (the distance from the edge of the door to the center
of the lockset) as the original lock, or you will have an irreparable mess!!
- Using the proper size hole saw, bore completely through the wood. You now
have a wood template to guide your hole saw through the door!
- Clamp your wood template firmly to the door in the exact position you want
the lockset, being careful not to damage the door surface with the clamps.
Use wood strips under the clamps on the back of the door if necessary. If
you have a problem juggling all these things at once, use some masking or
painter's tape to secure the wood strips before clamping.
- Before drilling, check one more time that the hole in the guide is the
right distance from the edge of the door. If you turned or flipped the
guide, it may not be! Make a measurement to be sure. It should be either
2 3/8" or 2 3/4" from the door edge to the center of the hole.
- Drill about 3/4 of the way through the door, and stop. Position the guide
on the other side of the door, and drill through till the two holes meet.
Remove the plug and... if everything went OK... install the new lockset.
Your new lockset is just a
tiny bit larger than the old one...
To the left is a typical lockset hole, which was about 1/4 inch too
small for the new lockset. Rather than make a hole saw guide, I used a
rasp to bevel the outside of the lock hole. Do this on both sides of the
door. Be careful not to enlarge the outer edge of the hole too much, or it
may show around the rose of the lockset.
Hole saws have a tendency move on surfaces unless the pilot drill bit is
into wood. Move is an understatement... they will jump like a cat on a hot
tin roof, damaging anything they touch, including you!
So to safely
enlarge an existing hole using a hole saw, you must get the hole saw engaged in
the hole before using the power drill. By hand, insert the hole saw into
the hole and rotate it by hand... back and forth... until it has cut at
least 1/4" or more into the door. (Using a rasp as mentioned above
can also start the hole.) Repeat on both sides of the door.
Put the hole saw into your drill, insert it into the hole, and bore the
hole, drilling 3/4 of the way from one side and then finishing the cut
from the other side. Be careful to start your drill at a low speed to
control the saw until you are sure the saw won't "jump" out of
I have tried to impress on you the relative risk of this method compared with
the more mainstream method discussed earlier. Whichever method you choose, take
your time and be sure of your measurements, because mistakes may be permanent!