Security-conscious residents and businesspeople frequently fortify their doors by installing one or more tubular deadbolts. A tubular deadbolt is the most common “add-on” lock because it is relatively inexpensive and easy to install. Although it operates by a simple mechanism, it can be a very strong and challenging barrier for burglars or firefighters attempting to force entry. A deadbolt, which costs as little as six dollars, can make forcing a door a difficult ordeal for firefighters who underestimate its strength.

To successfully and rapidly force entry of doors secured with tubular deadbolts, a door must be properly sized up and the correct tools and techniques must be used. Personnel who perform forcible entry must be able to rapidly recognize tubular deadbolt locks and have a thorough understanding of how they are installed and operate.

Usually, it is not difficult to recognize tubular deadbolts. Most can be readily identified by a characteristically large lock cylinder, usually mounted four to six inches above the original doorknob lock. Lock cylinder assemblies for tubular deadbolts typically measure two to three inches in diameter and project one-half to one-quarter inch out from the door. This relatively large profile is necessary because the cylinder mounts on the surface of a door. Only the back of the cylinder is slightly recessed into the hole in the door. The cylinder is held on the surface of the door by two screws that connect to another cylinder or thumbturn on the other side of the door. The two mounting screws, which thread into the back of the cylinder mounted on the outside of the door, in effect squeeze the door between the two cylinders. Obviously, the two cylinders must be larger in diameter than the hole in the door; otherwise, the mounting screws would pull the cylinders together into the hole. To increase their overall diameter, lock cylinders for tubular deadbolts are commonly fitted into a large collar rim. Some locks have the key plug-and-tumbler mechanism built into a large decorative escutcheon. These accessories allow the mounting screws to tighten the thumbturn against the inside and outside face on the door and facilitate pulling the cylinders by providing a purchase point for a prying tool.

The lock cylinders or interior thumbturn actuates the deadbolt that slides out of a tubular housing recessed into the edge of the door–hence, the name “tubular.” Deadbolts can extend as much as two inches into the doorjamb. The lock cylinder is connected to the deadbolt mechanism by a tailpiece that transfers the turning action of a key to a lever at the end of the tubular housing that extends and retracts the deadbolt. You can see the tip of this lever on most deadbolts. It is visible behind the deadbolt, recessed into a notch at the top of the tube. This lever has a range of motion of roughly 10 to 2 o`clock or 2 to 10 o`clock as it slides the bolt in and out of its strike in the doorjamb.


Effective and professional forcible entry operations begin with a size-up, when firefighters assess the obstacles to entry and fire conditions. Information gained in a size-up has a profound impact on the method chosen to force entry, select tools, and determine how much damage to the property is acceptable. Following are some factors that should be considered in a size-up before firefighters go to work on a door locked with deadbolts:

How is the door constructed and how strong is the door?

How are the door frame and adjoining wall constructed? How strong are they? Look beyond the door. Wall construction determines how much a jamb can flex when it is spread away from the door. A size-up may indicate that it would be faster and easier to breach a wall than to struggle with a difficult door.

Does the door open toward or away from the forcible entry team?

What are the strength, design, and operating characteristics of the lock?

What is the brand name of the lock? A brand name can tell much about a lock–its strength, design, and resistance to forcible entry, for example. Noting the brand name of a lock that is particularly difficult to force can save firefighters much time and effort. The forcible entry team may call for power tools immediately or select another route of entry.

Is the door locked with single or double deadbolts? Single or double relates to the number of lock cylinders on a deadbolt lock, not the number of deadbolts. A single deadbolt has a lock cylinder on the outside of the door and a thumbturn device on the inside that can be operated without a key. A double deadbolt has a cylinder on both sides of the door and, of course, requires a key to unlock the door from the inside. The presence of single deadbolts in a building is important information that should be ascertained by prefire planning. For example, with prior knowledge, a fire company can gain quick entry into an apartment from the public hallway by punching a small hole in the gypsum board wall, reaching in, and operating the thumbturn to unlock the door.

Thumbturns are becoming less common, however, because many people feel more secure with a lock cylinder on the inside of their doors. Unfortunately, double deadbolts can be extremely dangerous for occupants of a structure fire and for the firefighters who must enter and search for the occupants. People who lock their doors with double deadbolts rarely heed the advice of our public education programs that urge them to keep the key in the lock or, at the very least, next to the door when they are home. Some of these folks will become fatalities, locked in their own homes. Flame, smoke, or fire gases can prevent an occupant from getting to their key in time to escape. A firefighter who encounters a lock cylinder on the inside of a door will have to force his way out if he is cut off from the door through which he entered. Unless you positively know otherwise, always assume a door is locked with a double deadbolt. Carry forcible entry tools as you search in case you have to break out of a door or window. Never expect that it will be possible to easily exit a structure through a door other than the one through which you entered. The other door may be locked with a double deadbolt.

What are the fire conditions? How far the fire has progressed in a building determines the hazard to life and the urgency with which forcible entry must be performed. The severity of smoke and fire strongly influences the choice of methods used to force a door. Deteriorating fire conditions and a lack of visibility can severely limit the amount of finesse or physical exertion needed for some methods of forcible entry.


Conventional forcible entry uses the force of hand tools maximized by leverage and skill to overpower door and lock assemblies. Prying or striking a door locked with tubular deadbolts may achieve entry faster than more sophisticated methods of forcible entry. Although just about any door will eventually yield to an axe, maul, or halligan, conventional forcible entry is most successful and appropriate on wood and lightweight metal doors. Certainly, heavy metal doors secured with deadbolts can be forced by conventional means, but it requires substantially more time, skill, and physical exertion.

The objective is to apply force to the doorjamb and lock assembly until one of them fails. Prying usually tears a wood door at the point at which the lock assembly is mounted or breaks a wooden jamb. Few wood doors that open inward can withstand the striking force of a 10-pound maul. Striking the lock cylinder can drive a deadbolt through a wooden jamb or knock the entire lock assembly through a door. How the lock fails depends on which is weaker: the door or the jamb. Pry or hit a metal door so it crushes and bends away from the jamb far enough for the deadbolt to clear its strike. Deadbolts, particularly the inexpensive variety, can bend and break from the shear forces exerted by hitting the lock or prying the door.

The success of conventional forcible entry depends on the weakness of a door, lock, or jamb and the skill, strength, and stamina of firefighters. Therefore, it is critical that the strength and construction of door and lock assemblies be assessed before attempting this method. A size-up of a substantial metal door locked with deadbolts will clearly indicate a different method of forcible entry.


The design and operation of most tubular deadbolts make them vulnerable to the through-the-lock method of forcible entry. This method may be the best option for firefighters who must force a heavy steel door without power tools. The through-the-lock method usually involves two steps: (1) removing the lock cylinder and (2) operating the lock mechanism by substituting a screwdriver or special key tool for the turning action of the tailpiece. An important variation of this method often is more effective because it is not always possible, necessary, or even desirable to separate the cylinder from a tubular deadbolt to operate the internal lock mechanism. The following is an explanation of both through-the-lock techniques.

Remove the lock cylinder. Cylinder assemblies for tubular deadbolt locks usually are too large to fit into the blades of a conventional “K” tool (designed for pulling mortise lock cylinders) or similar lock-pulling device. The size, together with the assembly`s being mounted on the surface of a door, however, makes it possible to pull tubular deadbolt cylinders.

Drive a narrow, wedge-shaped tool, such as a nail puller, the adz of a halligan, or a “K” tool designed specifically for tubular deadbolts behind the collar or escutcheon. A strong, tight-fitting cylinder may require the narrow dimension of an axe blade driven by a maul to gain the initial purchase point. Insert the halligan adz at this point and, with a prying action, widen the gap between the cylinder and door. The pulling force exerted by the halligan may break the two mounting screws holding the cylinder in place or pull them out of their threads in the back of the lock cylinder. When this technique is successful, the results usually are fast and impressive: The cylinder pops smartly off the door.

Leaving the cylinder intact. Strong, high-quality deadbolts manufactured in the United States often use large, case-hardened screws to secure their cylinders to a door. These stout mounting screws are designed specifically to resist the efforts of anyone attempting to forcibly remove the lock cylinder. Even the less substantial deadbolts can be deceptively strong, making it very difficult to remove the lock cylinder. This doesn`t necessarily doom the through-the-lock method to failure.

If the cylinder won`t yield, perhaps the door will. Keep in mind that for every action there must be a reaction. The action, pulling the lock cylinder on the outside of the door, is transferred directly by strong mounting screws to the cylinder or thumbturn on the inside of the door. This action in effect pulls the inside cylinder into the door. The door is likely to react by crushing or caving in around the inside cylinder. Since the purchase point for the halligan is at the top of the outside cylinder, the pulling action has a tendency to tilt the bottom portion of the cylinder into the door. The reaction may result in a crushed area of the door at the bottom of the outside cylinder. Regardless of how or where the door crushes, it effectively reduces its thickness at the lock cylinder, thus widening the space between the outside cylinder and the surface of the door.

Continue to pull and pry until the hole bored in the door appears as a crescent-shaped opening above the top of the lock cylinder. The objective here is not to remove the cylinder but to create an opening just large enough to insert a screwdriver or pick and get a good view of the deadbolt mechanism. Pulling the cylinder any farther can misalign or damage the lock mechanism to a point at which it will not operate. Your target is the lever that slides the deadbolt in and out of its strike. Use a pick (ice, nut, dental) or a small screwdriver to lift the tip of the lever from its notch at the end of the tube, behind the deadbolt. Now, move the lever backward, away from the edge of the door. This action will throw the deadbolt to its unlocked position.

This variation of the through-the-lock method should be implemented at the first indication that the lock cylinder is not going to separate from the deadbolt mechanism. It is most effective (and appropriate) for strong locks installed on somewhat weaker doors. Of course, no method of forcible entry will always be successful. For this technique to work, the deadbolt lever must be accessible and operable. Heavy smoke can obscure visibility of the lock mechanism. One manufacturer of high-quality deadbolts features a steel shroud that shields the mechanism from manipulation. Failure of the through-the-lock method leaves the entry team with three options: attempt conventional methods, find another entrance, or call for power tools.


A steel door stiffened with internal reinforcing ribs and covered in heavy sheet metal can be a formidable barrier, especially when it is locked with one or more high-quality deadbolts. Substantial steel doors usually are hung in a steel frame of equal or greater strength. Forcing such a door by conventional means is particularly difficult when it opens inward because you must work the prying tool past an integral rabbited jamb and around the edge of the door.

A hydraulic forcible entry tool is ideal for the combination of a heavy, inward opening, metal door and a strong steel (rabbited) jamb. Hydraulic forcible entry tools designed for inward-opening doors work best when their spreading jaws work against a strong solid door and a rabbited steel jamb. Insert the hydraulic jaws near the locks, between the door and the jamb. The hydraulic hand pump spreads the jaws apart, forcing the door inward and destroying the integrity of the deadbolts.

Several lock manufacturers advertise that their deadbolts cannot be cut with a saw. They make this claim because their locks feature a solid, hardened-steel deadbolt or have a hardened-steel rod that runs through the center of their deadbolt. These features may deter a burglar with a hacksaw but not firefighters operating a rotary saw.

On doors that open outward, insert the aluminum oxide blade in the space between the door and the jamb, and saw through the deadbolts. It is critical, however, that the space between the door and the jamb be wide enough to permit the composite blade to spin freely without any binding. To widen this space, drive the adz of a halligan in between the door and the jamb. If more clearance is needed, push down on the halligan (tilting the adz) to spread the door and jamb farther apart.

A rotary saw can also effectively cut deadbolts on metal doors that open inward. This procedure, however, requires that a skilled operator cut the door along the jamb because the space between an inward-opening door and the jamb is not directly accessible from the outside. Plunge cut the door at the lock, as close to the jamb as possible. Pull the doorknob if it gets in the way of the jaw. Carefully guide the blade as it cuts the door at a slight angle toward the jamb, but avoid cutting deeply into the jamb. With proper technique, the saw will cleanly cut the deadbolt flush with the edge of the door.

A heavy-duty air chisel designed for vehicle extrication can greatly enhance the capabilities of the through-the-lock method of forcible entry. The air chisel will rapidly shear the lock cylinder from inexpensive deadbolts. For more substantial locks, use the air chisel to cut an opening in the sheet-metal skin of the door to permit manipulation of the deadbolt mechanism without pulling the lock cylinder.

Tubular deadbolts are the most common and challenging locks firefighters encounter when performing forcible entry. Firefighters can increase their capabilities in forcing doors locked with deadbolts by familiarizing themselves with door and lock installations in their jurisdiction. They should consult with locksmiths in the area. They are an extremely valuable source of technical information on locks and new products being introduced by the lock industry. Clearly, many techniques used by a locksmith are too intricate for the fireground, but a locksmith willing to lend his expertise can help firefighters maximize the effectiveness of their tools and techniques. n

(Top) Two different locks show the strength variations in cylinder mounting screws. The bottom lock is a high-quality deadbolt that uses 516-inch case-hardened screws. It is designed specifically to resist the efforts of forcible attempts to remove the lock cylinder. The top lock is a good but less substantial deadbolt using smaller mounting screws, making it possible to pull and separate the lock cylinder. (Bottom) The lock cylinder, fitted into a large, decorative escutcheon, is connected to the deadbolt mechanism by a tailpiece that transfers the turning action of a key to a lever that slides the deadbolt in and out of its tubular housing. When access to the unit is made without removing the lock cylinder, a screwdriver can be inserted to move the lever that throws the deadbolt into the unlocked position. (Photos by Justin Wasilkowski.)

(Opposite page left and right) Wood doors usually tear when they are pried near the lock assembly, allowing the deadbolt to clear its strike in the doorjamb. (Top left) Striking the cylinder with a maul can drive the entire deadbolt assembly through a wood door. (Top right and bottom left and right) Prying with the halligan tool crushes and bends this inward-opening metal door and allows the double-cylinder deadbolt to clear its strike. (Photos by W. Latimore.)

Three through-the-lock operations: (Top left, center) The axe blade is driven by the 10-pound maul to shear off the deadbolt cylinder or gain a purchase point to pull it. With the cylinder removed, the door is easily opened by operating the deadbolt mechanism with a screwdriver. (Photos by H. Pardo.) (Top right, middle left and right, bottom left) Steps of the through-the-lock method on a door locked with a tubular deadbolt. The mual drives the adz end of the halligan tool behind the escutcheon ring to gain a purchase point. The firefighter pries upward on the halligan to pull the lock cylinder away from the door. The lock cylinder pops off the door when the mounting screws fail (note the cylinder falling in mid-air, next to the lower deadbolt). The screwdriver is applied to the mechanism. (Bottom center and right) The maul-and-axe method also works for opening iron security gates fitted with deadbolts. (Photos by Tom Kenney.)

(Top left, right) Firefighters gain entry at this fire operation through an iron security gate and a metal door, each locked with deadbolts, by using a rotary saw equipped with an aluminum oxide blade. The deadbolt and doorknob latch are cut flush with the gate. (Photos by Ray Bell.) (Bottom left, right) The deadbolts on an outward-opening heavy metal door are cut with a power saw. It is critical that the space between the door and the jamb be wide enough to permit the blade to spin freely without binding. The adz end of the halligan, driven by a maul, widens the space between the door and jamb. (Photos by W. Latimore.)

(Top and bottom left) Hydraulic forcible entry tools will easily overpower the deadbolts on this inward-opening metal door. (Photo by W. Latimore.) (Bottom right) Cutting deadbolts on inward-opening metal doors requires skilled operators to carefully cut into the door as close as possible to the jamb. (Photo by Justin Wasilkowski.)

BILL GUSTIN is a captain with the Metro-Dade County (FL) Fire Department and a lead instructor in the department`s officer training program. He has taught cruise ship crews firefighting skills, has instructed in Caribbean countries, and was a member of the International Rescue Task Force for the U.S. Office of Foreign Disaster Assistance. He is an editorial advisory board member of Fire Engineering.

No posts to display