Introduction: From Blank Keys to Working Keys Without Dismanteling the Lock (using a Handfile)

You've probably seen lockpicking explained on several "hacky" websites. You
might even have tried it yourself. But what if you need to open a lock a number of times? Wouldn't it be great to have an opening technique that would supply you with a working key in the process? A method to do this has existed for quite some time, but until some years ago it has remained quite unknown. Impressioning locks got "re-invented" by the lockpick community and the skill evolved to the level now shown at several international championships. What is it? How does it work? What skill is involved? Why is it the most interesting way to open a lock? These questions, and more will be answered in this instructable.

Step 1: Blank Key

To start of you need a blank, uncut key that fits in the lock. Preferably it should be brass, but other materials do work.

During the impressioning process, we will need to search for tiny marks on the surface of the key. As you can see in the picture the untreated surface is rather rough, so marks will be hard to see.

Step 2: Prepping Key

A quick swipe with a file will take the toplayer off.

If your file is too fine, the surface will become too shiny. (which will be a bad thing in one of the next steps)

I recommend a swiss cut #4 file for this step

Step 3: Smoothed Blank Key

The idea of this step is to get a consistent surface (preferably non-shiny). This will make it WAY easier to recognize marks.

Step 4: Getting Initial Marks

While applying a moderate turning force on the key, rock the key up-and-down.

Turn the key in the other direction and repeat the rocking motion.

Using too much force WILL break your key. Using too little won't produce marks. Practice makes perfect.

Make sure you have backups

Applying just enough force will probably not work bare-handed.

You can either spend WAY to much money on over-engineered equipment like

or go for something simpler (and way more effective) like

I use a custom grip made by

You can also use a normal vicegrip

Step 5: Identifying Initial Marks

Using a magnifying aid will help tremendously in identifying marks. If marks are hardly visible, changing the angle of the key can make a huge difference.

Other possible tools are or

Step 6: Filing the First Cuts

On the spots where marks are visible, remove some material.

Try to leave sooth surfaces in the valleys you are creating.

Correct spacings and depths can be found here :

Which can be checked with calipers

Step 7: Rinse, Repeat

Put the key in the lock again and repeat the turn-and-rocking motion described earlier.

After examining the key you might find marks in the valleys you just created, or on new spots.

File those spots.

Step 8: More Rinse, More Repeat

Keep repeating this process.

At some point you might see "crater marks"; marks that are WAY bigger. These marks don't always occur, but when thy do they indicate that cut is almost at the correct depth. Be careful not to file away too much material!

Step 9: Success

If done correctly, all of a sudden your key will turn! This will either mean you broke your key or .... SUCCESS !!

You have created a working key. If this key won't turn smoothly, check for cratermarks and remove a tiny bit of material.

Step 10: More Info ..

Unlike lockpicking, impressioning creates a fully working key for the
lock which can be used to lock and unlock the cylinder at will. With practice, this technique can consistently open a lock in 10-15 minutes (and potentially faster)!

The pictures for this instructable we made by Hack42's very own Dennis van Zuijlekom

Good job Dennis, they came out great!

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