What is a tension Wrench?

A tension wrench, also called a tension tool or torque wrench in locksport, is a thin, L-shaped or bent piece of metal used to apply light rotational pressure to a lock cylinder's plug while picking. It is inserted into the bottom or top of the keyway alongside a lock pick, and it's the tool that actually turns the lock once the pins are set — the pick sets the pins, but the tension wrench is what opens the lock.

What is a Tension Wrench Used For?

A tension wrench is used in nearly every non-destructive lock opening method, including single pin picking (SPP), raking, and lock bumping. Its main purpose is to hold rotational pressure on the plug so that, as each pin is pushed to the shear line with a pick, the pin stays set instead of falling back into place. Locksmiths and locksport hobbyists use tension wrenches on pin tumbler locks, wafer locks, and disc detainer locks, adjusting the tool style to match the keyway size and shape.

How Tension Wrench Works

A tension wrench works by applying steady, light torque to the lock plug in the direction it would normally turn with a key:

• The tension wrench is inserted into the keyway, usually at the bottom.

• Light rotational pressure is applied and held with the fingers or thumb.

• A pick is inserted above or alongside the tension wrench to manipulate the pins.

• As each driver pin is pushed above the shear line, the slight plug rotation traps it in place.

• Once all pins are set at the shear line, the plug rotates fully and the lock opens.

Getting the tension right is the most important skill in lock picking — too much pressure binds the pins incorrectly, while too little lets set pins fall back down.

Main Characteristics of a Tension Wrench

• Made from thin, flexible spring steel or stainless steel for consistent feedback

• Available in multiple widths and lengths to fit different keyway sizes

• Common shapes include standard L-shaped (bottom of keyway), top-of-keyway (TOK), and twist-style wrenches

• Designed to leave enough room in the keyway for a pick to work alongside it

• Used for both pin tumbler locks and wafer lock systems

These characteristics make tension wrenches adaptable across almost every mechanical lock a locksmith encounters.

Advantages of a Tension Wrench

• Enables fully non-destructive lock opening with no damage to the lock or door

• Works alongside nearly any pick style, including hooks, rakes, and diamonds

• Compact and inexpensive compared to other opening tools

• Provides tactile feedback that helps locksmiths feel pin behavior during picking

• Essential for both professional locksmith lockout calls and locksport practice

How to Make a Lockpick Tension Wrench

Locksmiths and hobbyists sometimes make their own tension wrenches from basic materials when a specific size isn't on hand:

• Start with a strip of spring steel — a cut-down windshield wiper insert or hacksaw blade works well because it holds tension without snapping.

• Cut the strip to roughly 3–4 inches long and about 3–4mm wide, thinner for smaller keyways.

• Bend one end into an L-shape (or a slight twist for TOK styles), leaving a short foot to enter the keyway.

• Smooth any sharp edges with a file so the tool doesn't scratch the keyway or bind against pins.

• Test the tension wrench on a practice lock, adjusting the bend angle and foot length until it applies smooth, controllable pressure without flexing too much.

While making a DIY tension wrench is a useful skill-building exercise, professional locksmiths generally rely on manufactured tension tool sets for consistent quality and a wider range of sizes for different keyways.

CLK Supplies stocks a full range of tension wrenches and tension tool sets alongside lock picks and practice locks for both professional and locksport use.