# A Basic Guide to Impressioning, by Simon Barber 11/11/2010

Impressioning - The Basics

Part One: Equipment. There are many different techniques to successfully Impression a key to a lock, and the important thing to re-member is that whatever technique you use, if it works for you, then that’s all that matters. These notes follow the technique I use in order to impression cylinder locks. Some basic equipment is required to carry this out successfully, as follows:- 1. ~ ‘Dressing file’ (This can be any small, flat file with a fine cut to it.

2. ~ ‘Wet & Dry’ sandpaper, used ‘dry’. 1200 grit. 3. ~ ‘Clamping device’ for clamping the key bow, so that a small amount of leverage/torque can be attained. (Some have used very small ‘vice grips’ of about 4” as you don’t want an excessive amount of leverage or the key will break, but ‘vice grips’ can have a tendency to slip sideways, and if you are serious about Impressioning it is preferable to either buy, or make an ‘Impressioning Clamp’) Most of these are lightweight aluminium, with more expensive versions having ‘quick releases’ for the keys, however a perfectly good ‘clamp’ may be fabricated from any aluminium or steel bar, as all that is needed is for the key to be moved up and down and rotated slightly under pressure. Aluminium is generally favoured, for being light-weight, though I personally prefer a heavier steel one. 4. ~ ‘Impressioning file’. This, along with the next item, is by far the most important, and can mean the differ-ence between mastering Impressioning, or giving up. The file needs to be very fine, in order that it leaves a clean cut to the key with no file-marks that a ‘standard’ file will cause, thus ensuring the ‘impression marks’ stand the best chance of being seen. Some experts will advise the use of a ‘pippin file’, which has a cross-section like a ‘teardrop’ or ‘pip’, but personally speaking, I prefer to use a ‘round’ file, which can be ‘rolled’ slightly to one side or the other, if your ‘file points start to ‘drift’. I use a ‘Glardon Vallorbe no. 4 Smooth Cut Swiss file’ which is very smooth, and apparently actually improves the more you use it. Fit a good wooden han-dle too, and make sure it doesn’t come off, as the ‘tang’ of the file can be a bit painful if it imbeds in your wrist. When not in use, always store your file in a cardboard tube to protect it, as the surface is very fine, and prone to damage, which in turn will not produce a uniform ‘file stroke’. 5. ~ ‘Magnifier’. Like the previous item, the ‘right’ magnifier can make the difference between impressioning successfully, or not at all. I must have tried half a dozen magnifiers until I found one that worked for me. Again it’s down to preference, and there is no right or wrong choice. Optical experts say never go over 20x magnification, as the qual-ity of the optics deteriorate, and the gain in magnification is offset against the flaws in the manufacturing process needed to produce higher magnifications. I’ve seen magnifiers being used successfully for impressioning, anywhere from 2x upwards. As a general rule though, expect to need one in the magnitude of 10x - 15x. The ‘Contest guys’, who Impression keys against the clock, tend to use bench-stand magnifiers, of around 2x or 3x with a smaller 5x magnifier

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# A Basic Guide to Impressioning, by Simon Barber 11/11/2010

built-in, which is great if you’re sat at a bench. As ultimately, we should all be attempting to become consistent at Impressioning in ‘real-life’ situations, which normally involves standing next to the door, then a more practi-cal ‘hands-free’ magnifier needs to be utilised. I found a 15x Eye-loupe which has several advantages, on eBay, from a Seller called ‘magnifying.glasses.and.tools’. Firstly, it is held in place, with a steel band that wraps around your head, and while this will make you look like something from ‘Star Trek’, it does mean that it can be placed over your eye when needed, and slipped up onto your forehead when not, which speeds up the proc-ess a great deal. The other advantage, is that it has a small built-in LED lightsource, which in some circum-stances can help in seeing the ‘marks’, but if working in good light, usually it’s not necessary. 6. ~ Broken Key Extractors. These are a must, and something you probably have already. You will break keys, though it happens less, the more you practice. 7. ~ Cylinder plugs. While not entirely necessary, some find they help. Essentially, keep any old cylinder plugs, put a blank key in, and taking a small round needle file, file across the pin holes, squarely, downwards until you see the key, then file a little more. Now save the plug, and remember which brand it is. Next time you see a cylinder of the same make that needs Impressioning, put your blank into your ‘prepared’ plug, and file across the slots you made when you prepared the plug, until you mark the key blank. Then remove the key, and you have a blank with the correct spacing for that particular brand of lock. Some use a razor blade to mark the blank, or even tap a small ‘awl’ down each pin hole to mark the key. Personally, I don’t use cylinder plugs, but some may find it useful. 8. ~ Keys. Use brass to start with. They are ‘kinder’ to your file and mark easier, but are more likely to break than steel. Once you feel confident with brass, try steel blanks. 9. ~ ‘Impressioning’, by Oliver Diederichsen. Last, but not least, is Oli’s book. No, I’m not on commission, but it’s worth it for the photos alone. It really helps to know what you’re looking for, ‘mark-wise’. Part Two: Techniques. 1. ~ ‘Dressing the key’. There are several techniques to ‘dress’ the key, including ‘knife-edging’, where the key is filed to a knife-edge’ in order to ‘thin’ the metal, which then ‘nicks’ when it encounters pins, and the ‘pull-back’ method, where the filed places resemble a saw blade, and the key is pulled back from the lock about a sixteenth of an inch, with the pressure from the pins marking the ‘saw points’. I tend use the ‘flat-top’ tech-nique though, as I find it works for me, as there is more metal on a flat-edge to actually ‘mark’, but again it’s personal preference. This is essentially just ‘flattening’ and ‘polishing’ the key blade edge. Hold the key squarely, and rest the top of the blade on a stable surface, with the bottom of the blade facing upwards, - as though you were putting it in a Rim Cylinder. Using the ‘Dressing file’, and keeping it level, file across the blade at the same time as running it towards the tip, so it’s running from bow to tip of the key as you file. If you’re using a fairly fine file, about 10 strokes should be enough. Then place the 1200 grade ‘wet and dry’ sandpaper on a hard, flat surface, place the key blade on this, and polish the key by moving it only forwards and backwards along the length of the key. Again, about 10 strokes should be enough. Check the edge with the magnifier. It should appear smooth, ‘clean’ and free from any heavy markings or ‘artefacts’, which are ‘fault marks’ within the manufacturing process. If it isn’t nice and shiny, polish again with the ‘wet and dry’. 2. ~ ‘Initial marking’. Some use soot, paint, marker pen or various other substances along the blade edge, to enhance the marks. Again, whatever works for you, but during the time I spent with Oli and Jos Weyers, I was told that if it’s done ‘correctly’, none of this is necessary for cylinder locks, (though wax works wonders with warded lever locks!). As a quick ‘aside’, if you’re ‘at the door’ and the lock is dirty, and not marking well, flush it out with Brake Cleaner, and give it a while to dry. The best locks to impression are clean, non-lubricated ones. Clamp the bow of the key into your clamping device nice and tightly. Put the key into the lock, and turn as far as you can, fairly hard in one direction. While exerting turning pressure, rock the key in a ‘see-saw’ motion. It’s best to try and picture a fulcrum, or balance point half-way along the key, and attempt to pivot it at that point. Carry out the ‘see-saw’ motion about five times, then turn the key the other direction, exert turn-ing force, and ‘see-saw’ it again the same amount of times. It is important to always do the same amount of ‘see-saws’ for each rotation, so it is balanced. So if you do three one way, do three on the other rotation as well, or five and five, or whatever you prefer, but usually five is about right. This is called a ‘round’. Remove the key and examine it under the magnifier. Look closely and you should see one or more (hopefully more!) very small marks along the key blade. Some points may not mark at all, until quite late in the process though. They can appear as either bright ‘pin pricks’, or ‘dark marks’ that resemble a pencil dot. Much of this depends on light-ing, and the more you do it, the easier it becomes. If you don’t see any marks at all, try turning the key over, or

# A Basic Guide to Impressioning, by Simon Barber 11/11/2010

even hold it upright. Look at it in different lighting. All being well you should see around several marks. If you’re impressioning a five pin cylinder (which is a good place to start), then the ‘number one’ pin, is closest to the bow, with the ‘number five’ at the tip. The ‘number five’ is always a job to file as the file tends to rolls off, so you may find it easier to tip the key upwards for filing of the ‘number five’ point. So now you see some marks, put the key on a steady surface, and place the tip of the impressioning file on one of the marks, rolling it if necessary, until it’s in the correct place. Push the tip of your forefinger against the file, so it doesn’t ‘drift’. These first file strokes are crucial. Then run the first inch or so of the tip of the file across each visible mark in turn, remembering to brace the file with your finger so you are on the correct place. The purpose of this, is just to make the points at which you should file, clearer, and not really to remove metal. If you are unsure if you see a mark or not, then don’t file! This is very important. If it is a proper mark, it will become clearer later. Once you have made the marks clearer with the tip of the file, you can then run the full length of the file across each marked point, remembering to file only in one direction, - away from you, and always keep the file level. Don’t file at an angle. I find two or three decent strokes is about right, but it depends on your personal style, and the lock. With practice, you can gauge roughly how deep you’re going. Put the key back in the lock, and repeat the ‘rotation under tension’ and ‘see-saw’ motions, for both clockwise and anti-clockwise directions, remembering to do the same amount of ‘see-saws’ per side. Remove the key, and look for new marks. Sometimes they will appear to one side of the point at which you’re filing, which means you have drifted off the mark slightly. When this happens, ‘roll’ the round file towards the mark slightly as you file, and this will bring it back on track. The marks will also move from one side of the key to the other as the pin follows the profile of the key, as more is filed away. You may also notice that some of the filed ‘crescents’, have a dark mark running along them, resembling a pencil line. This is the pin ‘dragging’ along the ‘crescent’ as you push in, or withdraw the key. Remember at all times, if you’re unsure if you see a mark, then do not file. If you file too much away, you could well be stuffed! It’s much better to file a little at a time really. Repeat the process, with more ‘rounds’ and ‘filings’. Try not to exert more pressure on the key during the ‘rounds’ than is needed, as they are so easily broken, especially if there is a deep cut at the ‘number one’, or ‘two’ position. Ideally, you should aim to suc-cessfully impression the key within 10-12 ‘rounds’ or less, as anything much over this, is likely to break the key due to fatigue. I always keep an eye out for ‘fatigue’ marks, and go gentler if I see one. If it ‘does’ break in the lock, you can use your extractors to remove it, and file a ‘copy’ to match it, which saves starting from scratch again. When you’re on about the fourth ‘round’ you will probably have some very ‘serious’ peaks on the key! If the key does break, these ‘peaks’ can make it almost impossible to remove the broken section, so the simple solution is to remove the peaks as they appear. Just take the sharp tops off, with the ‘dressing file’. Later into the process, usually about ‘round six’ or so onwards, you may notice some very deep gouge marks in place of the usual ‘barely visible marks’. At this point you can get excited! These ‘crater marks’ (as Oli calls them), are the marks of some of the pins being so close to the shear-line, that they are forced over the key blade, or onto the ‘filed crescent’. When you see one of these ‘crater marks’, go slowly with the filing at that filing point, as it will only need a little more filed off. Not all points will have ‘crater marks’ at the same time, and some never will,- they will go from a ‘standard’ mark, to the correct depth in one filing. When all points are at the correct depth, the lock will open. Sometimes it will open, but stiffly. If this happens, inspect the key again for faint ‘marks’ and remove a very small amount, - usually about a single, light stoke will be enough. It is extremely easy to file too deep at this stage. If you go too deep, it has been know to take a punch and punch the metal up around the point that is too deep, but it’s kind of a cop-out really. When you have a ‘working key’, run the file down the length of each side, to remove any burrs, and use the flat ‘dressing file’ to remove any nasty ‘peaks’. When you’re happy with the key, you can always put it in your key-cutting machine, and cut a ‘proper’ one. I hope you find this basic guide useful, and that it inspires you to give impressioning your best shot. Following the techniques outlined above, and using the equipment mentioned, I went from getting nowhere, to taking 22 minutes to impression a key, and then to 81 seconds. With practice, it’s possible to achieve consistent times of around 2 or 3 minutes.