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Impressioning Tools for Beginners

Updated: Feb 24, 2021

One of the things that inadvertently always comes up when talking about impressioning is tools; honestly, I struggled with this part of getting started with impressioning, and in my own experience speaking to other people it can be one of the most significant barriers to entry.

I won't be talking about the best tools or all the tools you will need, but rather what tools I have found useful, and where I can, I'll provide links and references to where you can buy them. None of the links in this article is affiliated, and I can't speak for the quality of them unless specified (and even then it's a personal preference thing).


Before you get started the first thing you'll need is a file. It seems pretty obvious, but picking the right file can be difficult if you aren't too sure exactly what you need.

Most files available at Bunnings and other hardware stores are made for metalworking, not the soft brass metal type of working, think forged in blood, sweat and tears kind of metalwork, so we can scratch buying a file from Bunnings off the list.

Instead, you're looking for a jewelers file. I use a number 4 swiss cut which is a round file. There are arguments for and against teardrops. I won't be getting into that though because this is about the equipment you need to get started and not the best and worst of each tool.

If you have the funds, I'd also recommend getting a w i d e r file. This will help cut the sharp tip off those deep cuts that can cause your key to get jammed.

Light and Magnifying Glass

I've tried all sorts of lights, soldering lamps, LED lamps, all types. My home is filled with defunct lamps that I bought with the expressed idea of using for impressioning and god, were they awful.

My house is also filled with magnifying glasses. No mattress, just lamps and magnifying glasses, including a little eyeglass used by jewelers.

While the eyeglass has been useful and sentimental, it can cause you to obsess over small details and notice marks that aren’t there. So for your first one, steer clear.

The best lamp I have found available is one that I have been asked to look after until the next time the owner is in Australia. The SECOND best lamp I found was a sewing or tapestry lamp available at stores such as Spotlight or Lincraft.

Pro tip: While this lamp appear to be robust enough to survive a flight to Europe it is not.

For beginners a plain hold magnifying glass can get you a long way, especially if you can find one with a built in LED light, but as you look to getting faster, you will find having to pick it up, check, put it down and REMEBER WHERE YOU PUT IT every time will get tired after a while. I’m not too sure on magnifying strength though, I am long-sighted so wear glasses AND use a magnifying glass. The reality is you’ll probably go through a few until you find the one that has the right amount of light to magnification ratio, and works for the workspace you have.

My original magnifying glass was similar to this one available for $2 on Aliexpress. Be aware though, it is $2 on Aliexpress:


Toothbrushes... I have some strong feelings about toothbrushes and comes down to this -- don't use any random toothbrush you have lying around the house.

Why? Why can't I reuse any old toothbrush I have lying around the house?

The answer is simple.

You like having clean teeth, or dentures. But the reality is you probably take the time and buy a good quality toothbrush, with little rubber bristles that are good for massaging gums and cleaning tongues but the truth is, this only gets in the way and makes cleaning the key blade harder.

You don't need pearly whites when dealing with brass; you just need to keep the blade clean, that's why I'd always recommend the cheapest blandest toothbrush you can find. For frequent fliers or travelers, airplane or hotel toothbrushes are perfect.

If you're a zero-waste fan, bamboo toothbrushes can also be good. If you're worried about the ick factor, disinfect the toothbrush, and you should be good to go after all the key is going into a lock and not into your mouth!

Spacing Guide (Optional)

Spacing guides aren’t a necessity, and they are probably one of the hardest items on this list to source, at least for me that was the case. Now spacing guides come in different flavors each with thier own pros and cons.

The Gutted Keyway

The construction of a gutted keyway is relatively simple. You remove the core from the key way you plan to learn on (I’d recommend you start with just one for simplicity’s sake) take out all the pins, springs and other surprises, then cut the top off so the top part of the key is exposed when inserted.

You can then use a Texta to mark the spacing for your initial cuts, and put it in during to ensure everything aligns (mostly). Obviously the downside to this design is you don’t have the benefit of having a depth gauge, but who uses those anyway!

I’d also recommend never lending it to anyone, lest you lose your best spacing guide and need to start again. Below is a picture of a spacing guide @InfoSecFriends made for me last year.

* If you know someone who owns and operates a mill.

The Gutted Keyway PLUS PLUS

If anyone is familiar with Jos Weyers (@josweyers) from watching one of his wonderful talks at Lockcon, OzSecCon, or another conference, or perhaps from watching one of his world-record performances in an impressioning competition -- he has this freaking snazzy gutted keyway with the pin positions replaced with steel drill bits. The idea being, you put the key in, give it a gentle turn (not the same way you turn a key, but enough to strike the drill bits) and take the key out, this results in the initial spacing marked out.

This design helps speeds up the initial key setup, which in European competitions happens after the clock starts, but you will still want a gutted keyway to check for alignment (and subsequently identifying marks).


I’d argue that once you get started calipers become less of a requirement, however, they can be very handy at the start to understand how much you cut with each stroke of the file.

It also sort of brings us to depth gauges, which are different to spacing guides, as one shows us the amount of space between pins, and the other, the depth of the cut we are trying to identify. There are different types of depth gauge all with their own merits, some people like using keys that have been cut to the depth of each pin almost like you had a bump key for each pin depth that you can use calipers to compare against.

Schlage SC1 5-Pin Depth Keys
Schlage SC1 5-Pin Depth Keys

If you’re handy with a laser cutter you can make a depth guage similar to the badge made by Jan-Willam at Lockcon 2018 which allows you to slide a key in and identify the depth of the cut.

You can also use a pair of digital calipers and cross reference a depth and spacing sheet. My preference is for analogue calipers, some clear tape and Sharpie lines shakily drawn on. The reason being, my cuts don’t need to be perfect, they just need to be good enough and so it tells me if I need half, one, or two more cuts to get closer to the depth I am aiming for.

A pair of quick probe mechanical external measurement calipers with marks on 1, 2, 3.5 and 4.5.
An artists rendition of my calipers and how they are marked.

When I am competing, I will often use my calipers to make sure I’m roughly where I want to be, that is, if I am currently at a Abus C83 depth 2, I will cut a few times and make sure I’m approximately at a 3, this means that if I see another mark, I’m probably looking at a 4.

I think of it as “Dial before you Dig”.

Sign that has a big cross over a digger arm and shovel, the sign says "Dial before you dig"

Good quality analog calipers tend to be a little harder to come by, but if you do find yourself looking I would recommend making sure they spring open, and preferably one of the inside lips is flat, so it doesn’t slip off the narrow key blade.

A good example is the ‘Kroeplin - Schnelltaster zur Außenmessung’ or the ‘Holex Außen-Schnelltaster', however, on the rare occasion you can find clones on e-Bay for significantly lower prices than the official ones. If you do go down this path, you’ll want to buy them at a 0-10mm scale and 0.1 precision.

Digital Calipers:

Analog Calipers:

At the time of writing I wasn’t able to find an example I was comfortable linking here, as they all relied on you pressing the button to close them (which can result in off readings) or were vintage and listed for upward of $200.

Gaffer Tape

A must have to help protect your fingers from the charming weird coating found on keys and metal shavings. It’s especially helpful if you don’t plan to use the toothbrush simply because it will stop you getting the coating and metal shavings stuck in your thumb. (Trust me, it suuuuucks).

You’ll also find that it helps protect your fingers from the metal file, and you might be thinking, she’ll be right! I have thick skin on my hands! Which might be true, I will not doubt that, but given enough files in the same place, you’ll notice just how hot things start to get.

In conclusion, there is a higher upfront investment required to get started, however, many of these tools will last you years in the hobby. If you’re looking to get started those are the main tools that will make up an impressioning toolkit. If you just want the bare minimum to start with, you should probably get:

  • File

  • Magnifying glass

  • Light

  • Calipers

  • Spacing and depth sheet

TOOOL Australia would love to hear about your impressioning adventures and what has worked for you. We can be reached via the contact us form on our page, or in the comments below!

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1 Comment

Nice article. I must say that I've never considered a toothbrush nor tape, but my skin is fairly robust. Anyone with finer skin might do well to heed your advice on that.

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