How to Use a Tension Wrench for Lock Picking
The tension wrench is the most important tool in lock picking. Not the pick.
The wrench.
You can sometimes open a lock with just a tension tool, but you’ll never open one with only a pick.
This guide teaches you how a tension wrench works, how to control pressure, how to read feedback, and how to practice legally on personal locks or clear training locks.
What a Tension Wrench Is
A tension wrench (also called a torsion wrench or turning tool) is:
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A thin piece of metal
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Bent into an L or Z shape
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Designed to fit inside the keyway
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Used to apply rotational torque to the lock
Tension Wrench:
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Replaces the key’s turning pressure
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Holds pins at the shear line
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Provides feedback through your fingertips
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Controls everything about the pick process
If the pick is the “probe,” the tension wrench is the engine.
Types of Tension Wrenches
L-Shaped Wrench (Standard)
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Strong and simple
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Works on most keyways
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Good for beginners
Z-Wrench / Double-Ended Wrench
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Two thicknesses in one tool
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Fits tight or wide keyways
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Great for EDC kits
Top-of-Keyway (TOK) Wrench
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Rests in the top of the lock
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Very stable
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Great feedback
Bottom-of-Keyway (BOK) Wrench
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Most common
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Works with almost every lock style
Compact EDC wrenches, such as those on Grim Workshop cards, provide the same function in a lightweight, thin form factor perfect for practice locks and low-torque environments.
How a Tension Wrench Works
When you insert the wrench and turn gently, you create:
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Rotational tension
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Binding order (pins bind one at a time)
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Shear line alignment
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Feedback through vibration and resistance
Too much tension → pins won’t move.
Too little tension → pins drop back down.
Finding the perfect middle ground is the goaHow to Hold a Tension Wrench
Finger Pad Grip
Best for beginners — light pressure, high control.
Feather Touch Grip
Hold wrench with only fingertips.
Lets you feel tiny clicks and pin movement.
Thumb Lever Grip
For locks requiring slightly more pressure.
Reverse Grip
Used when applying tension from the opposite direction.
How to Insert the Tension Wrench
Bottom-of-Keyway Method
Start here:
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Insert wrench at the very bottom of the keyway
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Ensure it doesn’t block your pick
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Apply light pressure in the direction the key turns
Top-of-Keyway Method
Useful when:
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You need more control
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The bottom is too tight
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Lock has security pins
Insert the wrench at the top shoulder of the keyway.
How to Apply Tension (The Core Skill)
Step 1: Insert Wrench
Place it firmly but gently.
Step 2: Turn Slightly
Apply a tiny amount of rotation.
Think the weight of a pencil.
Step 3: Hold That Tension
Keep your tension stable as you begin picking.
Step 4: Adjust Tension as You Pick
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Too tight? Ease up
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Too loose? Increase slightly
Step 5: Feel for Feedback
You should feel:
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Clicks
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Resistance
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Movement
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Changes in torque
This is the “communication” between lock and fingertips.
Understanding Binding Order
Pins bind one at a time in a specific order based on:
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Manufacturing tolerances
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Wear
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Lock design
Your tension wrench creates this binding order.
You pick whichever pin binds first — then the next — until all reach the shear line.
How to Use the Tension Wrench While Picking
1. Standard Pin Setting
Workflow:
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Insert wrench
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Apply light tension
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Use pick to lift first binding pin
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Feel for click
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Move to next binding pin
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Continue until lock rotates
2. Raking With a Tension Wrench
For rake picks like snake, city, or jiggler picks:
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Insert wrench
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Apply slightly firmer tension
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Rake pins rapidly
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Release tension briefly
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Tighten again until lock turns
Pairs with:
→ Using Your Rake Lock Picks
→ Using Your hook Lock Picks
→ All Tools with Lock Picks
3. Using a Tension Wrench for Overset Recovery
If a pin oversets:
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Ease off tension
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Allow pins to drop
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Reapply controlled pressure
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Continue picking
4. Testing Keyway Direction
If you don’t know which way the lock turns:
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Insert wrench
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Apply light tension in one direction
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Try slight pressure in the opposite direction
The correct direction typically:
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Feels smoother
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Allows slight rotation
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Feels less “stiff”
How Much Tension Is Correct?
This is where most beginners struggle.
Light Tension
Best for:
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Standard pins
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Soft springs
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New locks
Medium Tension
Best for:
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Worn locks
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Old hardware
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Door locks with weak tolerances
Heavy Tension
Rarely used — typically only for:
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Stuck cylinders
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Binding cores
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Locks with internal grime
Most of the time, beginners use too much tension.
If nothing is moving, lighten up.
Advanced Tension Techniques
Feathering
Micro-adjusting pressure while lifting pins.
Pulsed Tension
Tiny pulses while lifting each pin to feel movement.
Reverse Tension Picking
Used when security pins falsely set.
Floating Tension
Maintaining constant but adjustable torque based on feedback.
Using a Tension Wrench With Security Pins
Security pins include:
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Spool pins
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Serrated pins
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Mushroom pins
Your tension wrench lets you feel:
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Set
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False set
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Counter-rotation
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Shear line alignment
This requires practice on clear training locks.
How to Practice With a Tension Wrench
Use a Clear Practice Lock
Lets you see pin movement while learning tension.
Try Different Wrench Thicknesses
Different locks prefer different fits.
Rotate Directions
Practice clockwise and counter-clockwise.
Master Light Tension First
It's 90 percent of skill.
How to Improvise a Tension Wrench
If you’re practicing and don’t have one:
1. Paperclip (Flattened)
Bend into L shape.
2. Street Sweeper Bristle
Excellent spring steel.
3. Small Flat Screwdriver
Works in larger keyways.
4. Thin Scrap Metal
Trim and bend with your bending tool.
Common Beginner Mistakes
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Too much tension
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Changing tension during picking
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Blocking the keyway
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Not identifying binding pin
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Oversetting
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Ignoring counter-rotation
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Holding wrench too tightly
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Using wrong wrench thickness
Expert Tips
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The wrench tells you everything — trust your fingertips
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Use just enough tension to bind the first pin
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Ease up the moment pins stop responding
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Try top-of-keyway tension for better feedback
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Treat tension like volume control — adjust constantly
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With practice, you’ll feel the lock before you see it move
FAQ
Q: How much tension should I use?
A: Usually less than you think — start with very light pressure.
Q: Can I open a lock with just a tension wrench?
A: Certain cheap locks can be bypassed with tension alone, but this is uncommon.
Q: What is the best wrench thickness?
A: Medium thickness fits most locks. Thin wrenches work for tight keyways.
Q: Does the wrench go on top or bottom?
A: Both work — bottom is easier for beginners, top gives cleaner feedback.
Related Skill Series Posts
(© 2025 Grim Workshop. All Rights Reserved. Grim Workshop, Survival Cards, and all related marks are registered trademarks of Grim Workshop. This article is part of the Grim Workshop Skill Series educational archive. No content may be reproduced, republished, stored, or adapted without written permission. For compact lock picking tools, tension wrenches, and EDC practice lock kits, visit www.grimworkshop.com.)
