DRILLING LOCK CYLINDERS

BY MITCH BROOKS

Drilling lock cylinders is nothing new to the fire service; however, it does seem to be a forgotten art. This method of through-the-lock forcible entry can be of value when faced with commercial structures such as office buildings, stores, and other structures that have a lock that can be readily drilled.

Drilling cylinders is an effective and efficient way to gain entry into a structure without destroying a door, breaking glass, or losing the integrity of a door. This method of through-the-lock entry is ideal when facing a single lock on a commercial door with a fire alarm ringing and no smoke showing. It takes a little time, but not so much that it should be ruled out as a means of entry. The benefit of drilling a lock’s cylinder is that, if done correctly, the tumblers in the lock’s keyway are drilled out of the way, allowing the keyway to be turned with a straight-slot screwdriver or similar tool.

To successfully drill a lock’s cylinder, you will need the following tools:

  • A drill (electric or battery-powered), preferably with a keyless chuck so that you can operate it while wearing gloves.
  • A drill bit—3/16 inch or 7/32 inch offers the best cut because of the size of the tumblers. Anything bigger might catch on the tumblers or shavings, jamming the drill bit; anything smaller might not cut through the tumblers.
  • A spray-on lubricant.
  • A spring-loaded center punch or lock drilling jig.
  • A straight-slot screwdriver small enough to fit in the lock’s keyway or a key tool. (A T-handled screwdriver works best because of the added leverage on the handle; you may have to use a bit more force for the initial turn if shavings are lodged in the keyway.)

These tools and other through-the-lock tools can be kept together on the apparatus in a toolbox or tool bag as part of a through-the-lock entry kit.


(1) With a spring-loaded center punch, make a dimple on the face of the lock, above the cylinder keyway. (Photos by author.)
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(2) Place the drill bit into the dimple, and start drilling.
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(3) Cylinder locks with protective shrouds can be effectively drilled if you cannot spin them out with vise grips.
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To drill a lock cylinder, properly place the drill bit on the face of the cylinder to drill through the tumblers. This can be done with a lock drilling jig or a spring-loaded center punch (photo 1). The goal is to place the drill bit above the keyway, near the edge (photo 2).

Next, start drilling at a moderate speed, spraying lubricant intermittently on the drill bit where it meets the lock cylinder. This is the most important aspect of drilling cylinders. Without a cutting agent (the spray lubricant), there’s a good chance the cylinder would heat to the point of melting and welding itself together. Also, the spray lube flushes out the shavings that otherwise would jam the keyway, not allowing it to be turned. The spray lube keeps the drill bit from losing its temper (hardness) by minimizing heat buildup, which could melt the drill bit or cause it to become dull too soon. While drilling, you can feel the drill bit cut through the pins that make up the tumbler; usually there are five or six pins. An important point to make here is that moderate force should be applied to the drill so that the drill bit doesn’t get jammed or broken; also, excessive force will overheat the bit.

After the pins have been drilled (photo 6), insert a screwdriver into the key slot and turn it to unlock the door (photo 7). After the emergency is contained, simply relock the door in the same manner.

The success of this tactic depends on proper placement of the drill bit and use of a spray lubricant.


(4) The tools needed to drill lock cylinders are a drill, a drill bit, a punch, a straight-slot screwdriver, and a cutting agent.
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(5) Residential lock cylinders, commercial mortise lock cylinders, mortise lock cylinders with protective shrouds, and rim-lock cylinders can all be drilled effectively.
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(6) A drilled cylinder keyway ready to be operated.
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(7) Insert a straight-slot screwdriver into the keyway and operate the lock as if you had the key.
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If for some reason the cylinder cannot be drilled, a problem should arise while drilling (a broken bit or loss of battery power), or multiple cylinders are present, an alternate entry method would be in order: Pull the cylinder or cylinders with an A-tool or a K-tool, use conventional means (a halligan and flathead ax) to make entry, or consider using power saws. Under no circumstances should you try to drill into an electric lock such as those found on electric roll-down gates. These locks pose an electrical shock hazard.

One other note: Drilling lock cylinders on commercial structures and even residential deadbolt locks is extremely effective, but it should be limited to these types of locks. It is counterproductive and, in my opinion, a waste of time trying to drill automobile locks or padlocks. Use other tactics when faced with automobiles or padlocks.

As with all fireground evolutions, training is the key. Make this almost-forgotten art a part of your forcible entry “toolbox.”

MITCH BROOKS is a lieutenant for the Columbus (OH) Division of Fire and a 13-year veteran of the fire service. He is a state-certified fire instructor, a paramedic, and a rescue technician and is currently completing an associate’s degree in fire/EMS at Columbus State Community College.

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