Using the New Kobra Readers

I've been an automotive locksmith for almost 35 years now, and I've used just about every technique and tool there is to make keys to vehicles at one time or another...

I've been an automotive locksmith for almost 35 years now, and I've used just about every technique and tool there is to make keys to vehicles at one time or another. Since I grew up making keys by impression, that is still my fall-back method when all else fails, but my 55-year-old eyes make that a...

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When the Kobra reader is in use, as shown in Photo 5, a single tumbler is trapped inside the trap notch and then the slide is pushed in until the angled tip of the slide makes contact with the tumbler. When the slide contacts the tumbler, the index mark on the slide will align with the scale as shown in Photo 6, giving you the precise depth of the tumbler that is being read. Note also how the dimple on the side of the blade aligns with the face cap to show you which tumbler is being decoded. (Because of different designs of some face caps the dimple will not always align as perfectly as in the photo, but it will always be close.) The design of the Kobra Reader holds and supports the slide in the proper alignment regardless of its position, so it yields an extremely accurate measurement of the tumbler depth that would not be possible if the slide were free to “float.”

In Photo 6, the position of the slide indicates that the tumbler being decoded is a number three depth. The deeper the cut on the key, the deeper part “C” of the tumbler will extend into the keyway. A shallow cut will allow the angled tip of the slide to go further into the lock than a deep cut. The mark on the scale closest to the lock will be the shallowest cut in the system, while the mark farthest away from the lock will be the deepest cut. With a little practice, you can trap each tumbler in the lock and decode it in just a few minutes. And the lighted scale makes working with the Kobra Reader at night a real pleasure.



The process of using the Kobra Reader is easy and it will quickly become routine as you use the tool on a regular basis. All you have to do is follow the steps outlined below in order to decode most locks:

1. Push the slide as far in as it will go to cover the trap notch, then insert the tool into the lock as far as it will go.

2. Pull the slide back in order to expose the trap notch and then pull out on the tool until the tumbler drops into the trap notch.

3. Using the dimples on the side of the tool, determine which tumbler you have trapped.

4. Rock the tool slightly from side to side to make sure that the tumbler has dropped as far in to the trap notch as possible.

5. Push in on the tool to bind the tumbler, then while maintaining pressure on the tumbler, push in gently on the slide until it stops.

6. Take your reading from the scale on the tool and write it down!

7. Release the pressure on the tumbler and then push the slide in as far as it will go to lift the tumbler and release the tool.

8. Pull the tool out until the index on the side of the tool shows that you are in position to trap the next tumbler. Repeat the above procedure to read each tumbler in turn and then flip the tool over to read the tumblers on the opposite side of the lock.


When using the Kobra Reader, there are a few techniques that you need to understand in order to get the most from your tool:

Always begin by cleaning the lock with a good solvent or lubricant. The Kobra Reader is precisely machined to give you the most accurate reading possible, and dirt or crud in the lock will only make the job harder.

Make sure that the tumbler has dropped all the way to the rest position by rocking the tool slightly after the tumbler is trapped to fully seat the tumbler in the slot.

Push in on the tool to bind the tumbler as you take the reading so that the slide stops against the tumbler instead of lifting it.

When in doubt, make the cuts on your key high – you can always cut them deeper, but it's impossible to go the other way.

On older vehicles expect the tumblers near the face of the lock to be more worn, and give a deeper reading than the ones at the tip of the keyway.

On particularly worn locks, pulling out on the reader, rather than pushing in on the reader, may help you to get better readings.

The Kobra Reader is designed to work on door and trunk locks only. Do not attempt to use the tool on the ignition lock.

Once you have decoded the locks, you can cut your key and try it in the locks. When you have a good working key, you can generally use a simple progression to finish your key in the ignition. In the case of the Ford 10-cut system, I generally use try-out keys in the ignition after I have decoded the door lock.

Just as with any other tool, having a good understanding of the lock system that you are working on will make your job much easier. Even though I've been at this job longer than most in the business, I still look up most vehicles in a reference manual before I start just to make sure that I know which tumblers to expect in each lock.

For more information, contact Lockmasters Inc., telephone 800-654-0637, online at

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