If you have a lock related question we haven’t answered in any of the posts so far, ask it here and we’ll do our best to get you the answer.

From the time man first had possessions, he has been looking for a means of protecting those possessions. It is known that the cave man built a fire to protect his cave entrance from animals who would steal his food. He would also place religious statues in the entrance to protect the cave while he was off hunting. The superstitious nature of the early cave man ensured that no one would risk invoking the wrath of the god the statue represented by entering the cave.

As man became more civilized, superstition was not enough to keep other men from entering his home while he was away. The door was invented and intricately tied knots were used much like a padlock to secure it. Legend has it that one such knot, (the Gordian Knot), survived until 333 BC when Alexander the Great loosed it with his sword. This inherent lack of physical security, which Alexander the Great demonstrated, probably led to the invention of the more substantial locks that are still used today.

The Romans and the Chinese are credited with the simultaneous invention of the padlock. The Romans used a warded mechanism, and since their togas didn’t have pockets, developed keys which could be worn as rings. While many locks must have been made of wood or iron and most were padlocks for chests, some of the bolts and locks were made of bronze and have survived. The bolts had holes in them that would only accept a key of the proper shape and many of the locks had figural designs invoking that old protection of the Gods. These bolts, (see figure 1), may be seen in some museums and many of the ring keys were made of bronze and may be found in museums also.

 Figure 1

Also shown in figure 1 is an example of the barbed spring typical of a Chinese padlock. The key acted directly on the spring(s) which were formed to simulate the effect of a fish hook when the lock was locked. Examples of this mechanism have shown up in cultures throughout the world and are still actively used to this day in some areas.

Our use of the word Padlock was established in the 1300’s in England.  Thieves in those days would follow behind wagons and coaches and ply their trade.  They were called footpads and the lock that could stop them became known as a Padlock.

Padlocks today are available with a variety of locking mechanisms ranging from the simple ward to lever tumblers to pin tumblers or combinations and even electronics.  Any lock that is portable is a padlock and great advances have been made in materials and design.

The ASTM, (American Society for Testing and Materials), organization has updated their standard F883 to a 09 version.  The revisions constitute a new test for bump resistance in pin tumbler cylinders.  Such a standard testing method has been needed for some time now.  Many manufacturers tell locksmiths that their products are bump resistant but there is little qualification of how much resistance is provided.

This standard will eliminate that problem as it gives locksmiths a standard way to measure bump resistance through some stringent testing.  The test requires each manufacturer to submit 5 samples of the cylinder to be tested and each cylinder must be supplied with 7 operating cut keys.  Why 5 cylinders?  To test the validity of a solution you need to demonstrate that it is successful repeatedly, in this case, 5 times.  Why 7 keys?  Many cylinders that claim bump resistance are patent protected to the point that blank keys aren’t available to allow making a bump key.  If extra keys are supplied with the cylinder to be tested, some of them can be turned into bump keys.

Three locksmiths conduct the testing and each locksmith must be familiar with bumping techniques and have had good success in the past 2 years using the technique.  Each locksmith gets 2 of the operating keys supplied with each cylinder.

Each locksmith turns their operating keys into a bump key, actually two bump keys for their are two design types that must be tried in each lock called a Pull and a Push.

Once a locksmith has made his bump keys he canstart testing.  The test for each cylinder must be completed at a rate of 10 impacts from each type of bump key every 2.5 minutes to a maximum of 60 impacts within 15 minutes.  Some pretty significant testing when you consider that the same test muct be performed by each locksmith.

The chart below shows the various grade levels at which a cylinder can qualify.

There is of course one original operating key that isn’t turned into a bump key.  That key is used at the edn of the test to determine if the lock will still operate after this concentrated attack.  If it won’t operate, the grade level isn’t changed since rendering it inoperable by the attack is a good form of bump resistance.

Remember this testing when looking for a bump resistant lock and ask the Grade level where the lock qualifies.

When a locksmith talks about key control he doesn’t mean holding the right side up when putting it into a lock.  What the locksmith means talking about key control is that you can choose a kind of lock with a key that can’t be made just anywhere or by just anyone.

Most of us can see the business applications of such keys to protect inventory and property or make sure someone can’t come in after hours because they have a key.  There are important non-business applications for key control too.  Your home for example.

As an example, did you realize that when you go out and have a valet park your car you have just put yourself at great risk?  You did!  You probably left your house key on the ring with the car keys.  Do you have the insurance papers or registration in the glove box?  They do have your address on them don’t they?

There are other situations where you may be giving your key to someone who knows your address that put you at just as much or more risk.  Be careful out there, there are people who are just waiting for you to make their lives easier.

If you don’t have a key control type key it can be copied in just a few minutes, usually under 5 minutes.  A robber only wants to be inside a house for 10 minutes to be safe.  If you just had your car parked he can be pretty sure you aren’t going to pick it up for at least an hour.  He can drive to your address in the same amount of time it takes you so that means he will have an hour to rifle through your possessions before you might get home.

Yes, a valet and an accomplice can pull a pretty good haul from your home if you don’t have key control.  So, how do you get key control?  You have to ask for it.  Most locksmiths have one or two products that they carry that offer patent protected key control.  That patent protected part is important too.

Patent protection means that only the maker of the lock can make keys to enter his lock.  Because he has the ability to stop anyone else from making his keys, he also has the ability to limit the number of places that can cut them to your combination and under what conditions they can cut them.

Ask your local locksmith if he carries a key control product.  Many will only carry a High Security product that offers key control along with better physical security than what is typically available.  Those are mostly demanded by businesses who want a UL437 listed product that can resist picking and drilling attacks as well as offering key control.

Most of the products in the marketplace that offer key control are of a better quality that ensures better pick resistance.  The price difference between a key control product that is drill resistant and one that isn’t is significant.  The drill resistant product will be 2 to 3 times more expensive and it will require a more upscale grade of hardware to be installed.

Tell your locksmith you want patent protected keys at a reasonable price.  Such things are available for Grade 2 commercially aimed locksets that have reasonable pricing for the residential customer.  You may want High Security after investigating but patent protected key control can stop the valet with an accomplice.

I’m aware of two brands that offer key control at a reasonable price.  Master Lock has a patented system they call EDGE™ and there is an Australian company called BiLock.  Ask about them both at your local locksmith because you can’t get them anywhere else.

If you have a business there is another aprt of Key Control that is important and that is knowing where all the keys are, when they were given out and when they will be brought back.  We found a software package online that can help with all thsoe things and many more, check it out at http://www.Locksoft.com

Years ago the standard size for a cross bore was 1 ½” in diameter.  In order to include baffles and some other features the standard has changed to 2 1/8” in the last few years.  If you are replacing an older lock with a newer one, that can be a problem.  There are also cases where you might want to change the backset from 2 3/8” to 2 ¾” or vice versa.  Making either one of those changes can be problematic if you don’t have an installation jig and those jigs typically have a price tag of hundreds of dollars.

There is a simpler solution that will typically be good for one or two uses before you need to make a new one.  The tools you will need are:

• A drill
• A hole saw with the correct diameter
• Two C-clamps with 3” clearance (or more if your door is thicker than 1 ¾”
• Two pieces of ¼” plywood about 6” square

The first step is to measure from one edge of one of the plywood sheets to the center of the backset you want to put into the door.  Then use the hole saw to cut a hole in the plywood at that backset.  Clamp the plywood sheet to the door in the proper location using the two C-clamps and the undrilled plywood to avoid damaging the door.

The next step is to remove the lead bit from the hole saw.  Then place the hole saw into the hole in the plywood and carefully start the drill and push the saw toward the door.  Be careful to not have the saw touching the door yet when you start the drill as it could bite too deeply into the door and possibly cause damage to the door, or to you, if you don’t have a firm grip on the drill.

As you drill through the door the hole saw will encounter the other sheet of plywood and having it there will prevent the saw from tearing the surface finish of the door when it breaks through.  If your door has a grainy surface you may want to use the added precaution of covering that surface with masking tape as well to prevent tearing when the saw breaks through.  If you tape the door, always remove the tape after drilling by pulling it toward the hole, never away from the hole.

To use the template on another door, just remember to use an undrilled area of that inside sheet of plywood.

This is generally encountered if your lock is a mortise lock.  Many mortise locks have something called a split spindle.  A split spindle is what allows the inside to work independent of the outside when it is correctly adjusted.

If the inside knob becomes loose the adjustment of the split spindle can be affected.  The easiest way to get the door open is to pull firmly on the inside knob when turning.  That will in effect restore the spindle to the correct operating position and allow the knob to turn again.

Once the door is open, look on the knob shank for a screw.  The screw is usually the slotted type and you should find it around the 5 or 7 o’clock position.  Loosen it until the knob can turn without retracting the latch and then turn the knob clockwise until it just begins to get tight.  Then turn the knob counter-clockwise until the screw is at the 5 or 7 o’clock position and tighten the screw as tight as possible.  That should allow the knob to turn freely and always retract the latch.  If it doesn’t turn freely, loosen the screw and turn the knob ¼ turn counter-clockwise before tightening the screw again.

Usually the outer knob is permanently fixed to that side of the spindle.  If the screw will not tighten or if the knob still turns without retracting the latch the inside of the spindle has become stripped or too rounded and you will need to replace it.  Your local locksmith is the most likely source for a new spindle and will exchange the outside knob for you for a small added fee and show you how to set it before putting it in the door.

More correctly called a spring latch or a deadlocking latch, you definitely need to know the difference.  Latches are lock bolts designed to automatically lock the door when it is pushed closed.

Latches have one side that is beveled and that side impacts the strike and pushes the entire bolt into the door.  Once it is aligned with the hole in the strike plate, the bolt springs from the door to lock it in place.

The only problem with that design is the ability to slip something like a credit card between the door and the jamb and push the bolt back with it.  A very easy defeat that doesn’t leave any sign of the unauthorized entry.

The solution to that design problem was a guard bolt addition to the latch.  When operating and installed correctly the guard bolt prevents the latch from moving or being depressed to unlock the door.

Operation is simple but the adjustment is routinely incorrect unless installed by a locksmith.  Here’s how you check that yours is installed and working correctly.

• Push the guard bolt in and then push on the latch.  If the latch won’t depress, the guard bolt is working correctly.
• Slowly push the guard bolt inward and every additional 1/16″ from full extension push on the latch to see if it will depress.
• Measure the distance from the edge of the door to the end of the guard bolt when the latch cannot be depressed and call that measurement A.
• Close the door and measure the gap between the edge of the door and the strike and call that measurement B
• If B is bigger than A the adjustment is incorrect and the gap between the door and jamb is too large.
• Adjust the size of the gap by adding shims under the hinge plate on the jamb.
• Loosen one hinge plate at a time and place a shim under the hinge, then tighten. (Washers work well as shims because you can put the screw through the hole and it will hold it in place).
• Once you have measurement B smaller than measurement A, it is correctly adjusted for depth and one more check to do.
• With the door closed, note if the guard bolt enters the hole in the strike plate.  If it does, that adjustment is not correct.

Only the latch bolt should enter the hole in the strike plate.  Hopefully the strike plate hasn’t been altered to allow the guard bolt to enter, only mis-located.  You can use the same tools that would be used to move the strike up or down, (see Building Settled), to move it to the proper depth that will keep the guard bolt depressed when the door is closed.

Don’t forget to reinforce the jamb.  If you still have that air space that will allow someone to deflect the jamb, they are effectively increasing measurement B and your door could be vulnerable to that credit card attack.

n.  a lock designed to be installed into a cutout in the edge of a door.  The lock body and most or all of its trim need no further assembly other than securing it to the door.

That definition pretty well describes the preassembled lockset. 

They are typically only found in commercial hardware applications and the retail price can be anywhere from $400 to $1200.  They are worth it though as they will likely outlast any frame building they are installed in and very unlikely to malfunction.  They are typically available with a  knob or a lever operating handle.

 In effect they form a sandwich with the door in the middle.  It was designed to strengthen a door as part of the installation.  If disassembled, they can be hard to reassemble correctly and it is suggested that they should only be serviced by a professional locksmith.

The interconnected lock is usually a combination of one cylindrical lock and one tubular lock operated via a single motion.  The single motion is turning a knob or lever handle. 

From the locksmith dictionary;

n.  a lockset whose trim provides a means of simultaneous

 retraction of two or more bolts which may also be

operated independently

Many brands of this type of lock can be found but just as commonly you will find that an exact replacement isn’t available because most manufacturers haven’t made one for more than 10 years at a time.  It will typically be possible to find a new replacement but it will be a different brand and may even have a different keyway that isn’t compatible with any other locks you may have.

The trim plate on the inside has a mechanism that makes it possible for the single handle to operate both locks simultaneously.  The primary purpose of these locks is to meet a local fire code that prohibits a locking scheme that makes the user perform more than a single motion to gain exit.

If you have the loose hinge or building settling problems, you will now have two strikes to adjust for a solution.  If there is a problem with the inside trim that doesn’t allow retraction of both bolts any longer, you should call a professional locksmith for repairs.

The definition from the locksmith dictionary says;

a lock for a door prepared with one or more

cross-bores and one or more edge-bores. 

There are some important features about the cross bore that need to be considered, especially if you are replacing an existing lock.

Backset is the distance from the leading edge of a door to the center of the cross bore.  Two dimensions are typical in the US, 2 3/4″ and 2 3/8”.  There are other standard backsets that have been used and one that came close to being a standard is 5 1/2″.

Another important dimension is the diameter of the hole used for the cross bore.  Most locks available in 2008 have a 2 1/8” diameter but there are other size requirements for some brands.  If you have a different diameter hole in your door that is too small, there is some good advice for redrilling the cross bore in the Redrilling a Door article.  If the cross bore is too large now your easiest option is to plug the hole and redrill it.

Most bored locks only require one of each type of hole, but there is a type of bored lock that requires more than one, the interconnected lock. 

There are two general types of bored locks;

• Cylindrical
• Tubular

A cylindrical lock has the locking mechanism in the part of the lock mounted via the cross bore.  You can check the type easily by holding the lock part that mounts through the cross bore and trying to lock it in your hand.  If the knob or lever won’t turn, it is a cylindrical lock, if it will turn, it is a tubular lock.

The Tubular lock is typically a deadbolt that is mounted separately from the key-in-knob or lever lock.  The original intent of the deadbolt was to be a secondary locking device to be used when no one was occupying the building. 

Deadbolts

There are two types of deadbolts, the single cylinder and the double cylinder.  The single cylinder only requires a key to operate it from the outside while the double cylinder requires a key from both sides of the door. 

Some municipalities have outlawed the double cylinder deadbolt because people have a tendency to lock them when they are in the building and that poses a hazard if there should be a fire or some other reason to leave quickly.  In a panic situation such as a fire very few people will have the presence of mind to get a key to unlock the door.  It also may be hard to find a key hidden near the door when the room is filled with smoke and fire.

Many locksmiths discourage the installation of double cylinder deadbolts because of this hazard but there is an alternative if you feel you require a double cylinder lock.  There are dead bolts on the market that capture the key inside and won’t release it until some other extra step is performed.  That typically should discourage not having a means of exit without consciously choosing to remove the key.

Knobs and Levers

The next type of bored lock is the key-in-knob or key-in-lever lock so typical in the US.  The same dimensional features are just as important with these types of lock and either type may be cylindrical or tubular in function.

The common shape has traditionally been a knob and the outside knob typically has a keyhole in it.  Along with the Americans with Disabilities Act mandates we have started seeing that tradition change.  It is becoming more common to see lever handles in these applications.

The most important feature to examine on these types of lock are the latch itself.  Check the article on latches for details.