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[Ultimate Guide] The Tension Wrench – Everything You Need to Know About This Crucial Turning Tool

lock picking tension wrench
Reading Time: 6 minutes

It seems like a simple tool. You just cram one end into the keyway and apply force to the other end, right?

Not really buddy…

If we take a step back and closely examine this crucial tool, we might notice some characteristics that spark some interesting questions. Some of which include:

  • Why do some have two ends with two different lengths?
  • What is the purpose of these two lengths; when do I use the short end and when do I use the long end? Does it matter?
  • Why do some tension wrenches have a twist and others don’t?
  • Is the standard tension wrench only for beginners and when should I abandon it for a top of the keyway turning tool?

I know, these are a lot of questions for such a small tool and the funny thing is that we are barely just scratching the surface. Let me explain.

The tension wrench is a very important tool in your lock picking set, there are so many questions that surround it and so many qualities that often go ignored.

However, by truly understanding these qualities you can better utilize this tool to its and your full potential.

It is time to take a dive into the world of tension wrenches. Grab a cup of coffee, seat back and enjoy the article.

You may also like to read:

  • 7 Best Locks to learn Lock picking
  • 7 Best Lock Picking Sets

The Tension Wrench – Nothing More Than a Bent Steel Bar

Nothing more than bent steel. A tension wrench is a simple tool, it is nothing more than a flat steel bar than has been bent at a 90-degree angle, consisting of both a short and a long end.

The shorter end is what usually goes into the keyway and most times reaches up to halfway through the keyway. This is the section of our wrench that acts as the blade of the key and turns the plug.

The longer end is what we pickers use as leverage to apply force to and turn the plug.

The tension wrench is designed and intended to be used at the bottom of the keyway (BOK) and is the ideal tool for picking a lock in your hand.

It is by far the most common turning tool found today and is the bread and butter of any good lock picking set!

There are tons of variations to the tension wrench though and we will go into that later in this guide but first lets take a look at what makes this turning tool so popular and any drawbacks you might have from using them.

Benefits of the Tension Wrench

1.) They are Cheap

The tension is basically a flat piece of metal with a few bends, this simple design mean its very easy for manufacturers to make leading to a relatively cheap price for us to buyers.

You can easily grab a good variety of tension wrenches for $10 — like the Peterson 6 Piece Tension Tool Set!

2. Provides Leverage for Your Pick

When picking a lock, we sometimes have to leverage our picks off the bottom of the keyway or some other lower point in order to fully lift a pin to set.

Certain locks though are designed in such a way that there are huge gaps between the pins and the area you can use as leverage. These huge gaps can make leveraging your pick and reaching those pins difficult. Unless…

…you leverage off your tension wrench. Genius right?

Using a tension wrench as a point of leverage can give you a higher point to leverage your pick from (that’s a mouthful) as well as reduce the distance between your pick and the pins. It also gives you a smooth base to slide your pick on.

3. Lock in Hand Comfort

When used in the bottom of the keyway the tension wrench sticks out an angle that is quite easy and comfortable to apply force to when picking a lock in your hand.

Due to this reason — and its cheap price — the tension wrench makes for an excellent beginner tool as most individuals learning how to pick a lock typically begin with padlocks that can easily be tensioned from the bottom of the keyway.

However, note that this benefit can quickly turn into a nightmarish drawback if you are left-handed.

Drawbacks of the Tension Wrench

As we can see the tension is truly an awesome tool with some really useful benefits, but unfortunately, nothing is perfect. Let have a look at some of the drawbacks of the tension wrench.

1. Binding the Core

A huge drawback for the tension wrench is that because you are turning the keyway from the edge, the force on the wrench can easily be transmitted directly into the body of the lock.

This results in a problem called — binding the core, meaning the plug won’t rotate. “Binding the core” can also be caused by using a tension wrench that is too small for the job. Take note of that.

2. False Feedback

Because tension wrenches are used at the bottom of the keyway, they tend to rub against the inside of the keyway.

This causes excess friction. Also if there are dents or nicks on your wrench or inside the keyway, you mak encounter false feedback or even bind your turning tool.

3. Too Much Rubbing

Because your tool is constantly rubbing against the bottom of the keyway, you can easily wear off sections of the lock and create a slight depression that your wrench can get stuck in.

This can sometimes make it impossible to continue using that particular tool on that lock.

Though this problem most commonly occurs with softer brass locks and steel ones

4. Can Take Up a Lot of Room

Perhaps the greatest drawback and the primary reason many pickers transition to a top of the keyway turning tool — such as a prybar — is because the tension wrench can take up a TON of useful room in the keyway.

This gives us as pickers less room to maneuver and leverage our picks and can make picking some locks very difficult, if not impossible.

Types of Tension Wrenches – Know Your Weapons

The foundation is set. We now know the pros and cons of the tension wrench. But what about their characteristics, what makes one type different from the other and in what situations should we use one over the other?

Before we dive into the answer to these questions. Let’s break the tension wrench into 3 different categories.

  1. The Straight Wrench
  2. The Twisty Wrench
  3. The Double-Ended Wrench

Note: There are other styles of tension wrench beyond these three, however, they’re not as common and it’s likely you will never use them. So to keep it simple we’ll stick to these three types of tension wrenches!

1. The Straight Tension Wrench

First up is the straight tension wrench! This little guy is nothing more than a flat piece of steel with a 90-degree bend applied to a single end.

tension wrench guide

To fully grasp the purpose of the straight tension wrench, it’s absolutely crucial we understand 3 things:

1.) Our number one source of feedback amongst our locking picking tools is our turning tools.

2.) We as pickers want to do everything in our power to use a turning tool that will provide us with the most feedback possible.

3.) The turning tool that will provide us with the most feedback possible will be one that is the thickest and stiffest.

This third point is the straight wrench’s triumph card!

Because the straight wrench is a straight piece of metal it will not bend or twist, it will remain rigid while you apply torque to it, thus providing you with a maximum degree of feedback!

It might be a bit difficult to put this into context without something to compare it to.

So to drive the point home, let’s look at a tool that is practically the exact opposite of the straight tension wrench, something thin and springy.

I am talking about the twisty tension wrench.