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The Lock Picker's Plague: Oversetting and Undersetting Pins

oversetting and undersetting pins
Last Updated on May 3, 2023
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The overset and underset have sent tens of thousands of unaware lock pickers spiraling into the depths of frustration, despair, and naughty words—some to lose their entire life savings to the swear jar.

Oversetting and undersetting pins occur when a pin is lifted to a specific position that can fool a picker into believing that the pin is set when it’s actually not.

Because the picker never actually set the binding pin and only thinks it is set, there can’t and won’t be a new binding pin to find.

But good news!

With a little knowledge of identifying, fixing, and even preventing these little predicaments, your sanity will be safe.

And if you are new to lock picking or need a little touch-up on the basics, consider reviewing my ultimate beginner's guide on how to pick a lock!

What Is an Underset Pin?

An underset pin occurs when the lock picker lifts a binding driver pin to the shear line but stops short of completely pushing the pin to a set state.

Because that particular driver pin is still binding, it can oftentimes remain where the picker leaves off raising it—that is somewhere between its resting state and a true set.

Pin State - Underset Pin

The underset can trick a picker into believing a pin is set because, like a true set, the key pin will no longer be under the pressure of the spring and will free-fall back into the plug.

How Do I Know if I'm Undersetting My Pins?

Identifying a pin as underset is a deductive process with two steps:

  1. The picker will realize there is no new binding pin.
  2. The picker will probe the key pins and find each of them either under spring pressure or loose in the plug. Remember, an underset pin will act like a set pin and allow the key pin to free-fall in the plug.

If you can’t locate a new binding pin and get some degree of springy feedback from every key pin, you can safely assume that you have an underset pin.

How Do You Deal With Underset Pins?

Without changing your tension, very gently apply a lifting force to each pin, starting with the pins you have already set—this is one of many reasons to be aware of what pins you set.

If you run through each pin and find that none of them are set, release a very slight amount of tension. Once again, gently lift each pin until you find the underset pin and push it to the shear line.

If you happen to release too much tension, the force of the spring will overcome the binding force on the underset pin, and it will fall back to its resting state. This will give you a fresh start to set the pin.

The last resort solution is, of course, to release all tension and begin again.

How Do I Stop Undersetting Pins?

The best possible way to prevent an underset is to ensure that every binding pin that you lift gives you both indications of a set—a physical sign such as a click and a loose key pin to follow.

Take your time and give each pin the love and focus it deserves.

What Is an Overset Pin?

The overset is our next monster, but what exactly is an overset pin?

An overset pin occurs when a lock picker raises a pin stack too far to where the key pin crosses the shear line. As a result, the key pin becomes the binding pin rather than the driver pin.

Pin State - Overset Pin

If the bind on the key pin is stronger than the pressure of the springs, it will remain stuck at the shear line, and you will not be able to progress any further until you knock it down into a set state.

How Do I Know if I'm Oversetting My Pins?

The first step in identifying an overset pin is the lack of any new binding pin. However, unlike an underset or even a true set, the key pin will not be under the spring pressure or loose in the plug. It will instead be rigid and hard to move because it's bound at the shear line.

So to find an overset pin, all you have to do is probe each key pin until you find the one that “feels” like it's missing—that is, the key pin that gives us no feedback when we touch it.

Another indicator that you will develop with time is that an overset pin will also be extra high when you feel it with your pick.

How Do You Deal With Overset Pins?

Fixing an overset is a whole other issue and takes a little practice to master.

If you have identified a pin as overset, your next step is to lower it back into the plug or push it to a true set.

To fix an overset, gently reduce tension and begin tapping the overset pin with the tip of your pick. Continue releasing small increments of tension and tapping the pin until it falls from the overset state.

Then set it as you would, being extra careful not to repeat your previous mistake.

How Do I Stop Oversetting Pins?

In essence, lifting pins is a subtle and gentle practice, and you should always treat it as such.

The best way to avoid an overset pin is to ensure that you are not forcing things. Instead, gently probe for a binding pin and then even more gently lift that binding pin until you get the indicators that the pin is truly set.

If something isn’t moving how you want or doesn’t feel right, don’t force it impatiently. Check the other pins first!

Wrapping It Up!

Remember that without practice, this guide is nothing but words. Take the time to develop your senses in regard to underset and overset pins.

Pick up any lock with standard pins and practice placing pins in false sets intentionally. Develop a sense for how they act—the way in which they are set, the feedback you get when you probe them, and how it feels when you fix them.

I hope you found this guide useful, and if you would like to learn more, consider checking out my Academy for more free lock picking guides. Also, if you are in the market for a new lock pick set, be sure to check out my lock picking shop!

As always, happy picking!

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