I'd first like to say that lock impressioning is not easy. You are not going to be an expert overnight, and you are not going to be able to impression every lock that you come across. It's a slow process as compared to picking, and requires an investment in tools and information that are not a requirement for lock picking.
The object of impressioning is to create a working key for the lock in question without disassembling the lock or using other "decoding" methods such as "reading" to decipher the combination of the lock.
If you plan on doing this for a long-term hobby/sport/profession, here's what you'll need (in no particular order of importance):
1. 6" Swiss #4 or #2 round or pippin file with a handle.
2. Brass File card or brush to clean file with.
3. A good pair of locking vise grips.
4. A good light source.
5. Key blank book.
6. Magnifying glass (if you've poor eyesight)
7. At least one metric ton of patience.
8. Keedex impressioning plate and vise.
9. A good silicone or teflon lube.
10. Cleaning cloth.
11. The right keyblank(s).
12. Blue Sharpie (optional).
O.k. Now that's in place, let's discuss briefly what can and cannot be impressioned in terms of locks.
The 2 and 4 track high security locks found in vehicles are one of the types that should not be impressioned without lock specific tools. These locks damage very easy because of delicate and split or "half" wafers found in the lock. Even inserting a blank key can potentially damage parts inside the lock.
Otherwise, anything else is pretty much fair game with a little innovation and some extra, lock specific tools that won't be discussed here. (yet.)
Got it? Good. Moving on.....
Choosing the blank.
The first step to impressioning a lock after acquiring the necessary tools, (and the lock of course) is to find out what keyblank is required. The easiest way is to look at the key that actually works the lock (if there is a key available). For our example, the keyblank I'm looking at has two sets of numbers "1145" and "SC1". This keyblank fits into the most popular residential Schlage locks including entry sets, handlesets, and deadbolts.
Keys will usually have numbers, or letters, or a letter/number combination stamped into them to identify what it is. If this is the case, you're set.
If you have a working key and it does not have any type of identifying marks, you're not out of luck yet.
Another method is find yourself an Ilco keyblank book (thanks to those who asked to make mention of the most popular manufacturer), or go to the local hardware store and ask THEM to find the correct blank for you. Basically what they do, is compare your key to pictures and profiles in a book, (like comparing criminal photographs, almost) until they find the correct one. Most of the time these catalogs can be acquired for free or a very low cost from a distributor. Your local locksmith may be willing to hand you his old book for free as well since they're updated yearly.
Now, if your lock does not have a key, and there's no name on the lock, latch, or strike plate, you're still o.k. Simply get some paper and trace exactly the shape of the keyway in the plug. Reference your keyblank book (which is handily broke into sections) and you should be able to identify exactly what keyway it is.
Example: Our Schlage lock has no key, but from the name on the lock, we can look in the keyblank book under Schlage to find the section with the most common keyways. After I trace the shape of the keyway, I can compare it with the profiles in that section to find the precise key I need.
Sources for blanks:
There are a variety of sources for blanks, and it will depend on your status (whether your a locksmith or have access to a supplier) and economics (how much you're willing to spend).
Listed in no particular order here are some sources:
1. Internet
2. Your local locksmith(s).
3. Hardware Stores such as Home Depot and renovation stores.
4. Retail stores such as Walmart or Canadian Tire or their like.
5. Mall kiosks that do engraving or sell novelty items like lighters, etc.
Always buy at least two blanks, and five or 10 would be preferrable. If you find yourself enjoying this a lot your best bet would be to become friends with a local locksmith who can get bulk pricing on keyblanks, or the owner of a hardware store who might be willing to cut you a deal on keyblanks that you need.
Lock Preparation
Once the correct blank has been selected for your pin/wafer tumbler lock, the next step is to prepare the lock for the task.
I know this is going to suprise some of you, but it is important NOT to lubricate the lock just before you decide to impression. Here's why.
Although the ideal situation is to have a perfectly clean and more importantly dry lock, unless you are working with a brand new, off-the shelf-lock this is not likely to happen. If you do want to give yourself the best chance of success, go ahead and thoroughly clean out the lock yourself either through disassembly, or heavy use of a lubricant to flush out the lock. Then, run your blank key in and out, wiping the debris off in between, until the blank comes out clean and dry. (This may take awhile.) Then let it sit and dry overnight just for good measure.
Lubricating a lock loosens any debris in the lock and allows it to go floating around, and it will most likely end up sticking on the keyblank and making it difficult to find those all-important marks that you need to see. Rubbing the debris from the keyblank may also cause those important marks to disappear, so now you understand why we don't want to do that.
If you do own, or can purchase a Keedex impressioning plate, you can clamp this in a vise, then insert your lock cylinder into one of the appropriate holes, clip it into place and you're ready to go. If you don't own one, you'll need to clamp your lock in a vise, or afix it in some manner that will allow you to comfortably do your work without strain. You can leave the lock in the door you're working on, of course, but I would suggest if you don't have a discreet place to work on it, to move the lock to a place where you can.
Great. Let's move on.
Keyblank Preparation
In selecting a keyblank, where possible, purchase blanks that are brass-colored (goldish). These will afford you the best opportunity to see the impressioning marks. Avoid steel (rare) and especially aluminum (dull-gray) as aluminum keys will twist and break too easy for this particular type of work. Steel keys are rarely found in hardware stores, etc. because of their expense, so don't worry too much if the only keyblanks available to you are the shiny silver ones. These are most likely a mix of brass and nickle, and are perfectly adequate for the task at hand.
To begin preparing your key blank, insert it into the lock you are about to impression. Then, slide your vise-grips onto the bow (the portion of the key normally gripped) of the key as close to the face of the cylinder as you can get without touching, then move them back another 1/8 of an inch (or 3mm) to allow for manipulation of your blank and clamp hard. Make sure the vise grips are very tight. We want as close to zero wobble as possible. Remove the keyblank and hold it on the edge of a table, or your knee with the blade up. (This is the part which will look like teeth when we're done impressioning.)
Examine carefully the top edge of the blade. You'll notice that it is a fairly "rough" finish with tiny lines and blotches going in all sorts of directions. Our goal is to get rid of these so they do not affect the presence of marks.
1. With the key blank held by our left hand (or reverse if you're a lefty) and our #4 Swiss file, (and in the forward direction only) in one motion from bow to tip, we're going to lightly rub this initial finish off. Now, here's a tip to remember. Start with the tip of the file against the shoulder stop of the key, push the file both forward (perpendicular to the key) AND towards the tip of the key. By the time you reach the tip of the key, you should have travelled at least equidistance along the length of your file (if not more) as well. Use no more than five or six light strokes if possible. An alternate method is to use light sand-paper. This is not a technique I've tried myself yet, but if it works for you, great!
2. Check your progress and insure that your "stroke" is even and level. Do NOT rock the file as you go across. A few light strokes should "clean" the surface of the blade to a nice matte finish with no surface blemishes. Remember that at this point we do not want to remove any more material than necessary, we just want a nice clean and mark-free surface.
Knife-edging
Knife-edging is a technique often recommended by some professionals for speeding up the process of impressioning. The idea is to thin the blade of the key to almost a point (like you would if you were sharpening a knife) to allow the pins/wafers to mark the material easier.
Here's how it's done. With the key in the same position as mentioned above, tilt it away from you at approximately a 45 degree angle and begin filing in similar strokes. After approximately 10-20 strokes, flip the key around and perform the same exercise on the other side. Eventually, you should end up with a similar clean, mark-free surface as mentioned before, except that you now have almost a semi-sharp edge on the blade of the keyblank. Be careful to remove as little material from the top as possible. In knife-edging, the "sharpened edges" are the important surfaces in this case, so make sure they are mark-free.
From my own personal experience, I must say I have had mixed results with knife-edging a keyblank to prepare it. Especially in regards to pin-tumbler locks, I've personally found it easier to see the appropriate marks without using the knife-edging technique.
I've mentioned it in this FAQ, though, because it is a valid technique, and greatly speeds up impressioning times for simple wafer locks and important for impressioning higher security locks such as those with nasty sidebars, etc.
Thanks to Mark for asking the question on the use of a marker on the edge of the blank to view marks. Can't believe I forgot to mention it. This method will actually work best if the lock is clean and dry, and I generally use a Blue Sharpie (when I use a marker) since it is easily discernible from lock debris. It is a viable method to use as well, and I would suggest it especially for beginner's as you will be able to more easily identify the correct marks. Be sure to clean the lock out well once you're finished though.
This completes the preparation phase.
Technique
Of all the steps involved in impressioning, technique comes second only to blank preparation in importance. You can have all the other stuff in place, but if you don't do this part right, you're in trouble.
Step 1.
With your vise grips centered and tight on the bow of the key blank, and the key prepped, insert the key into the lock.
Holding the vise grips comfortably, (ie. not a death-grip nor loose) turn the key CW firmly. Holding the key in this position, rock the key up and down quickly but not hard. I usually perform this action for a count of 5.
Step 2.
Stop the rocking motion, still holding the key in the CW direction. Then, allow the key to return to the original position.
Step 3.
Gripping the vise grips again, turn the key CCW and perform the rocking action once again for a count of 5. Cease rocking motion, then allow key to return to neutral postion.
Step 4.
Repeat steps 2 & 3 again.
Step 5.
Remove the key from the lock in one smooth motion. This is easy to do at the start since no filing has been done, but after a bit of time in the process may be complicated by cuts that have been made. Insure that the key is centered in the lock and ready for removal.
Step 6
Again in one direction only, give the visible mark 3-4 firm strokes with the file. I generally do not use more than the first 3 inches of the file to do this as I don't want the cut to go either too wide or too deep.
Looking for marks
Greg Miller describes what to look for very well from an experience standpoint, but I'll try to clarify a bit in hopes more of you will understand.
Keep in mind that during this process you are most likely NOT going to see marks in all positions all the time. In fact, you are most likely going to see only one or two each time. It is vitally important that you file in only ONE position during a cycle, and also important that you file just enough that the mark disappears, no more, no less.
The marks you are looking for will be round dots, circles, circles, or distinct lines (that eventually turn into dots or circles) that will become more pronounced as you get close to the proper depth. (with pin tumblers) With wafer tumbler locks, the marks will look more like extremely fine filing or minute dents on the edge of the blade. It is necessary to view the keyblank edge from as many angles as possible with a good light source. Any jagged lines, or squiggle marks should be ignored. Do not get upset if you don't see any marks at a given time, and DON'T GUESS! Simply go through your cycles again, and insure that the keyblank edge is "fresh" and "clean" of marks. You can remove the squiggles, etc. with very fine file strokes if you wish.
As a comparison, perform this: Take a pen (the type that you press the button on top to reveal the pen tip) and with the pen tip retracted, press it into your hand or arm firmly enough to make a mark. Then, watch carefully as that mark fades. The central "dot" basically performs in reverse the view you're going after.
When you begin hearing the pins "click" distinctly in the lock, this is a sign that you are approaching completion. Don't get excited, just continue your method. Once the lock turns, it doesn't necessarily mean you're finished either. You will need to continue the process until the key turns smoothly and/or the marks disappear completely. Keep in mind to only file where marks can be seen. Once the key works smoothly, your task is complete.
If you are performing this task for a customer, you'll need to duplicate the cuts onto a fresh blank. DO NOT give the key used to impression to the customer. The keyblank used has been stressed, and maybe crack or break suddenly, and I'll leave to you to guess who'll be responsible for removing it from the broken lock for free.
I'll leave this thread unlocked so that if you have questions, they can be discussed here. Be warned, once this FAQ is complete, all questions/comments will be removed and the thread will be locked as an FAQ. Thanks in advance for your assistance in making this a comprehensive FAQ.
Late.
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