Primer on Through-the-Lock Forcible Entry Technique: Truck Co Operations

Primer on Through-the-Lock Forcible Entry Technique

Trolling the Internet looking at different fire service websites and YouTube videos, I often come across training on through-the-lock forcible entry.

Instead of using our heavy-duty tools like our irons set with the Halligan and a striking tool like a flathead axe or maul, this technique uses much less force. Normally when we resort to the heavy-duty tools, it’s under emergency conditions, or when we’re faced with a heavily fortified door that requires the big guns to get through. This often causes extensive damage to the door and the doorframe.

The amount of damage we do during forcible entry should be based on a needs assessment of the incident: The faster we need to get in and more heavily fortified the building, the more damage is justified.

The vast majority of incidents we respond too, however, are investigation-type responses, including automatic alarms, odors, food-on-the-stove fires and welfare checks of citizens. During these types of incidents, we may be able to slow down and minimize the amount of damage we have to do to get inside and do our job.

Through-the-lock allows us to reduce damage and still accomplish quick, efficient and safe forcible entry. And with new forcible entry tools hitting the market every year, we have more options than ever before.


At its basic, through-the-lock is a technique where we use our ability to remove the front of the standard mechanical lock cylinder found on doors by pulling or removing the lock face and cylinder, exposing the internal components. We can then manipulate the internal mechanism to unlock the door, thereby minimizing the amount of damage done. It’s much easier and less expensive to replace the lock than to repair the door and frame.

Removing the Cylinder

Removing the cylinder face from the body of the lock is a critical step in the through-the-lock technique. There are a number of methods to accomplish this based on the type of lock and the quality of the lock. Less expensive locks are usually less difficult to force than more expensive, better constructed locks. Some of the lock cylinders that you find in most aluminum-frame commercial buildings are mortise-style locks that can either be pulled or sometimes simply screwed out of the body of the lock.

Another factor that will affect pulling the lock cylinder: the tools you have available to you. A wide variety of tools are effective in pulling the cylinder—from something as simple as a pair of channel lock pliers, to lock-pulling tools like the K-tool or R-tool (see photos, p. 63), to station-made or modified tools. There are also a number of techniques used to drill out the lock front with a cordless drill, providing an opening large enough to manipulate the lock with a screwdriver.

Cylinder Size-Up

If you’re faced with a mortise-style lock in the locked position, the spring-loaded pin inside the lock body will be away from the doorframe. After you have removed the cylinder from the lock body, take the time to size up the back of the cylinder by looking at the back of the lock. If the back of the cylinder has a cam, use the key tool end that has a pointed end turned down at a 90-degree angle. This angled tool allows you to reach inside the lock body and move the spring-loaded pin back and forth to open the lock.

Based on how the lock is positioned in the doorframe, the pin will normally be positioned in the 5 o’clock or 7 o’clock position (see photo, p. 62). You may have to push the pin down slightly to move it.

If the back of the cylinder has a piece of metal that looks like the end of a flat blade screwdriver, then select the end of the key tool that looks like a flatblade screw driver (see photo above) and use the flat point of the key tool to turn the lock until it opens.

Train to Be Ready

There are too many forcible entry tricks and techniques to cover everything in these few paragraphs. Make sure your forcible entry training is frequent and covers through-the-lock procedures on a variety of locks and doors. All of these methods are important for your company to understand and use when called on.

Tip: Develop your through-the-lock set of props by visiting your local locksmith. Most are happy to give you the old locks they have from replacement lock jobs; if they aren’t in the habit of keeping these old locks, ask them whether they’re willing to start doing so to support the local fire department’s training. Through-the-lock is great training around the kitchen table when you have a good set of props to work with.

When you face those incidents that call for less force and damage to the structure, remember to use your through-the-lock techniques to get the job done.



Clarion UX