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.

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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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    65 Discussions


    1 year ago

    I've been unable to source a brass key, i exect it to be steel of some sort but i havent spark tested it so I'm plannign on using machinst blue to mark the key. Would this work or do u think itll get marked up just going in and out of lock?


    1 year ago


    Hi, nice guide. Could you tell me where or what brand I can buy the key file your using?

    1 reply
    Moe Greatness

    3 years ago

    wouldnt it be faster to dismantle the lock and file it without needing to repeat the proccess multiple times

    2 replies
    MeisterJosMoe Greatness

    Reply 1 year ago

    My fastest time using this technique (during competition) was 48 seconds. Good luck doing an dismantle and re-assembly in that time frame :-)

    Besides that (competition does not equal real life) sometimes there can be very valid reasons not to take the lock apart (and this is way more fun :-))

    MeisterJosMoe Greatness

    Reply 3 years ago

    Dismantling is not always an option. But yes, that probably would be faster (not counting the time it takes to search for the springs that just HAD to jump out)


    Question 1 year ago on Introduction

    I have an old Bricard cylinder lock which was the second lock in the front door of an apartment I just bought.
    The owner lost the keys for it.
    I have changed the main lock to a brand new level 4 security lock, but I dont want to throw away the old lock because it is nice and solid. I cant get keys cut for it because they say they would have to take it apart.
    If I can obtain blanks and follow your step by step approach, do you think I could make working keys?
    I just want to use it for a store room.
    What do you advize?
    Thank you for the very interesting video. I was sure there was a way to make cooies from impressions of the cylinder.

    1 answer

    Answer 1 year ago

    Technically, I don't see any reason why you wouldn't be able to do so.
    I would advice to get a different lock and practice the technique a bit on a workbench first.

    But sure, go for it !


    4 years ago on Introduction

    just an idea...but what if you cast a blank out of lead so that the impressions are easier to see?...

    1 reply

    Reply 4 years ago on Introduction

    Impressions would indeed be quite easy to spot, but your blank would also break WAY to easily. I've seen some research where they replaced only a part of the key, mitigating the breakage, but still keep the advantages of lead.

    (haven't played with this myself)


    4 years ago

    It isn't just giving someone physical access to the key, it is also allowing someone to see your key for just a few seconds, or having them in a position where a photo can be taken.
    I know that Jos could make a key based on a quick glance (as can I).
    The part that most people don't realise is that this process which can be done in under 60 seconds, can be done over a period of days with only a few seconds at a time needed. Keys are easier to restrict access to than the locks themselves.

    Excellent instructable Jos.

    1 reply

    4 years ago

    Would using something like layout fluid on the top surface help to see the marks or not?

    1 reply

    4 years ago on Introduction

    Do not take my comment the wrong way but,

    If you allow someone to have your key they can easily take it to Walmart and have it duplicated.

    To maintain security do not share your key