What is Lock Rekeying?

Last Updated on November 21, 2022

What is Rekeying

One of the most common questions we get about residential locksmith service is, “Can you change my door locks?”

And, yes; we can. But “changing” new hardware is expensive and isn’t usually what the customer really wants.

More often, when a customer is telling us they want to change locks, they are really asking us to repin their current locks so that they work with a new key (a different key than one that works currently). We in the locksmith industry call this rekeying.

Lock rekeying is the process of replacing the internal pins inside of a lock so that any existing key can no longer open the lock. The locks will now open using new, different keys. You do NOT need to replace your locks when purchasing a home. You can keep your existing locks, while ensuring no one who was given a previous key can use it to get into your property.

When Should You Rekey Your Locks?

For improved security, you should rekey your locks when you have purchased a new home and are concerned that someone may have a copy of the existing key. Homeowners often give keys to neighbors and other people that are close to them. But these people (and their now teenage children) may not be so close to you. This is one of our seven Recommended Home Security Improvements you should do when buying a new home.

Also, if you’ve lost your key and you believe that someone may be able to tie that key to your home, then you’ll want to rekey the house. Say for example, you leave a copy of your key in your car and your car has been broken into our stolen, get a rekey.

Jump to:

• Which is Cheaper? Rekeying or Replacing Locks?
• What’s inside of a lock
• How does a key open a lock
• How do lock pins stop the wrong key from opening a lock
• What is master rekeying
• Rekeying locks to match an existing key
• DIY – How to Rekey Locks
• How to rekey a Kwikset Smarkey lock

Is it Cheaper to Rekey or Replace Locks?

Rekeying your locks is always cheaper than buying new locks. You can save up to 10X by rekeying rather than buying new locks because you are not replacing the door hardware. The savings becomes more substantial as the number of locks increases. To save the most money take your locks into a locksmith shop near you. By doing so, you avoid the cost of a service call to your home or business.

Internal Parts of a Lock

To understand how lock rekeying works, you need to have a little knowledge of how a lock cylinder is put together. Although every lock is a bit different, most common home and business locks have the same basic parts.

There is the lock housing, which is what surrounds the cylinder and holds it in. The cylinder (sometimes referred to as a plug) fits snug into the housing. It is held in place with some form of clip, cam, or nut that keeps it from being pulled out. Pictured here is a key-in-knob cylinder (the kind you would find in a door know or lever).

The lock housing and the cylinder both contain holes. These holes accommodate “bottom pins” like those shown in the photo. Those are the pins that come in contact with your key.

How Does a Specific Key Open a Lock?

When the working key is inserted into the lock, the top part of the bottom pins will be flush with the plug, as shown.

The bumps that are cut into the key will raise the key pins inside of the cylinder (shown in green) so that the key pins are flush with the cylinder. This is creates a shear line that allows the cylinder to rotate.

When the bottom pins are flush, the cylinder can spin (rotate). That is how the correct key opens the door.

How Do the Key Pins Prevent a Lock from Opening

There are also pins, call top pins, that are within the lock housing itself.

When the key is not in the keyhole, the pins within the cylinder are in a down position and the top pins of the lock housing slide down into the cylinder. The top pins are actually pushed into the bottom cylinder to fill the gap by springs.

These pins block the shear line and prevent the plug from spinning freely. This prevents something like, say, a screwdriver from opening the lock.

These 3 items (bottom pins, top pins, and springs) are secured either internally or with a spring cap, to keep everything held together.

When the wrong key is inserted into the lock, some of the pins will be below the cylinder’s shear line, and some will be raised above it (pushed into the holes for the top pins). Both of these situations block shear line so that the wrong key can’t open the lock.

What is Master Keying?

Instead of having one pin in each top pin location, you can create a stack of pins with 2 or more key pins. This will create a cylinder that has multiple shear lines.

That is, more than one cut key will create a shear line, so more than one key will open the lock.

This is called ‘master keying.’

Master keying is the process of rekeying a lock with multiple top pins so that the lock can be opened with more than one key. Master keying and is used in businesses extensively. For example, one person might have a key that accesses all of the office doors, but another’s key will only open their office door.

Check out our article “What is Master Keying?”

Rekey Locks to Match a Current Key (How to Use the Same Key)

Many times the need to rekey a lock occurs when a new lock is purchased and you want that new lock to use the same key you already have.

This is no problem, so long as you buy a lock that is the same keyway as your existing locks. The easiest way to ensure this is to by the same brand of lock from the same manufacturer.

But there are different lock brands that use the same keyway, so it’s not always necessary to get the same brand. In fact, if you are upgrading to electronic locks, the one you want could very likely be an off brand. See our article on Rekeying Locks to Match Existing House Keys. to ensure you get a lock that uses the same type of keyway.

How to Rekey Locks – DIY

Taking your own locks into a lock shop is one of the most affordable ways to rekey your own locks. See our article, “How Much Does it Cost to Rekey Locks?” But if you’re the type that wants to figure it out and pay the absolute minimum, then rekeying your own locks may be for you.

You can rekey your own locks by removing the lock from the door, taking out the cylinder and then replacing the bottom pins. But, as a practical matter, it may not be worth it. A single mistake can make the springs and pins fly out, all over the place, and you’ll need a professional locksmith to get it all back together or to replace the lock.

we’ve often had folks who’ve tried to go it alone come into our shops when something’s gong wrong.

If you are willing to take on the challenge, you can buy an inexpensive rekey kits on Amazon. This is really a case where you need the right tools for the job and a rekey kit is a quick and affordable way to get them.

If you are handy, it could be fun to try to re key the lock yourself. If it works, great! If not, just take the locks into a local locksmith shop and they’ll get it back together for you.

How to Rekey Kwikset SmartKey Locks

There is a lock manufacturer, Kwikset, that around 10 or 12 years ago designed locks for residential use that you to quickly and easily rekey your own locks. The product line is called SmartKey, and it’s a very different lock system that does not use pins and springs.

You can identify a Kwikset SmartKey lock by the extra little hole found near the keyhole.

ACME Locksmith sells rekey kits for Kwikset locks on our website at a very affordable price. It comes with everything you need in order to rekey your own Kwikset locks including the smart key reset tool and new keys. You can specify how many keys you’d like to have with the kit.

Rekeying a Kwikset Smart Key DOES require the existing working key, so if you do not have this, you cannot rekey the lock. A locksmith would be able to, though, using a special tool needed to reset the lock with a working key. If you do have the working key, it’s a fairly simple process.

1. To rekey a Kwikset SmartKey lock, insert the existing key into the lock and turn it 90 degrees in the direction to unlock the door.
2. Insert the smart key reset tool into the slot until you hear a click then remove it
3. Remove the existing key by pulling it straight our (do not rotate it back)
4. Insert the new key into the keyhole and now rotate the key back to the original position and remove the key
5. Check your old key to make sure it no longer works

Disclosure: As an eBay / Amazon Associate I may earn from qualifying purchases.