How to Find the Right Skeleton Key for Your Locks

How to Find the Right Skeleton Key for Your Locks

When you're trying to match a skeleton key to an antique or vintage lock, the first step is to determine which type of skeleton key you need. There are two main types:

Hollow-barrel skeleton keys

  • These allow a pin inside the lock to fit into the end of the key.
  • They are often smaller and commonly used on trunks or furniture pieces.
  • You can usually tell by looking to see whether there is a pin sticking out of the center of the keyhole.

Solid-barrel skeleton keys

  • These can be used on either furniture or door locks.
  • There is no pin in the lock, just an open keyhole.
  • The barrel of the key itself is solid.

Next, look to see if you can find a maker or brand name on your lock. This can be very helpful, especially if the key is also branded. However, don't focus on branding too much. While it is nice to have a matching key and lock brand, the shape of the key matters far more than the name on it.

Historically, just as today, key companies made generic keys designed to work with many locks. Many keys and pieces of hardware were never marked at all, so concentrating on shape will give you far more options.

Furniture and Trunk Keys

Once you determine whether you need a hollow barrel or solid barrel key, consider the following for furniture or trunk locks:

  1. General size and shape
    • Measure your keyhole.
    • Furniture key sizes vary significantly, so knowing what will actually fit helps narrow choices.
  2. Bit style
    • Some keys have bits (the projecting part at the end) on both sides.
    • Most have only one.
    • Consider how long the bit can be and how long the overall key needs to be.
  3. Pin size for hollow-barrel keys
    • If your lock uses a pin, measure how large it is.
    • The barrel must be large enough to fit over the pin, but not so large that it won't fit inside the keyhole.
    • The opening must be long enough to go fully over the pin so the bit reaches the tumblers.

From this point forward, matching is usually a matter of testing keys to see what works. Before testing, spray a small amount of WD-40 or lock lubricant into the lock. This often makes a big difference.

If you find a key that moves the bolt slightly but doesn't fully operate the lock, you're probably close. Focus on keys with similar shapes, but with minor variations, until one fully engages the mechanism.

The most commonly used furniture key shapes are the single-edge notch and double-edge notch styles. These are good starting points. If neither works, you may need to try more complex shapes.

Door Locks

Skeleton keys for door locks are usually easier to match because they almost always use solid-barrel keys. Still, small differences in size and shape matter.

First, make sure your lock actually uses a skeleton key and not a flat key. Skeleton key locks have a large, open keyhole you can see through. If possible, remove the lock from the door to inspect and test it. Testing keys is always safer with the lock removed in case one gets stuck.

Check the outside of the lockbox for markings. These may appear on:

  • the box itself
  • the deadbolt
  • the front plate
  • inside the lock box

Sometimes, especially if the marking is near the keyhole, it may indicate the key number needed. This is only useful if you can also find a matching branded key.

Inspecting and Maintaining the Lock

When you already have the lock removed, this is a good time for basic maintenance.

  • Look for paint buildup around the latch area.
  • If paint is present, carefully run a razor blade around the edges of the deadbolt and remove as much buildup as possible.

If you are comfortable opening the lock box:

  • Remove the screws and lift the cover slowly.
  • Parts may be under tension, so move carefully.
  • Take a picture of the mechanism before touching anything. This is essential; lock interiors vary widely and are not well documented.

Manually move the deadbolt to see if it operates easily. If paint or grime prevents smooth movement, carefully remove and clean the bolt and surrounding area until it slides freely. Add light lubrication. Look for internal markings or clues to key shape. You may be able to tell whether the key requires one notch, multiple notches, or a more complex bit.

Check for internal projections that limit key movement.

Testing Keys and Final Steps

Close the lock and examine the keyhole. Look for:

  • small internal projections
  • overall size of the opening

Projections may require:

  • a groove along the key, or
  • a very narrow key to fit past them

Larger keyholes normally require larger keys with larger bits. Keep the lock off the door while testing keys. If a key becomes stuck, loosening the lock cover is usually enough to remove it. This is much harder if the lock is installed.

As with furniture locks, there are two "generic" key shapes that frequently work with door locks. These are generally simple and small. Even if they don't fully operate the lock, they can tell you whether you need a base notch or a more complex bit pattern.

The good news is that in many old houses, if all the locks are original, one key often worked throughout most of the home. Once you find a working key (always test both sides), it may function in multiple locks in the same property.

 

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