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Brinks Rekey...Good, Bad, or Ugly? (locksmith hack)

I'll show you something, and I would be grateful if you could tell me how it's done. Let's have some fun. Are you ready?

I have a standard mortise cylinder here, nothing special. As you can see, it's a Schlage keyway.

 standard mortise cylinder

I'm going to be using three SC4 keys. These three keys are essentially all different because of the cuts on them.

 SC4 keys

On the first key, it works back and forth. So, it works like usual. But the next key can only turn to the left; it won't go the other way. It does not turn. The last key only turns to the right; it does not turn to the left.

 Locksmith tips

Do you have any idea about it, or are you confused as I am before? Greg Gibson sent in this lock. He's been on the channel in the past, I had an interview with him, and he talked to me about this over the phone. I was kind of following him, but he ended up sending me this cylinder. So, what I'm going to do is I'm going to crack it open, and we're going to look at it together. I believe this concept is called Brinks or Brink. So, if you know more about this and how this works, definitely fill all of us because I would love to learn more.


You'll notice marks on the cylinder. These are the marks that Greg put in, and he used a Dremel tool.

 lock cylinder

Tungsten carbide cutter square tip 3.2mm

If you are planning to replicate it, it's not an exact science; you have to be careful when you do it.

Let us break down how it works by starting with the key that works both ways. Notice that all the pins are flush. The grooves are still there; however, those grooves don't matter. And since all the pins are flush, it's going to have a turn on both ways. You might be wondering what happens when the top pin hits? Nothing. As the cylinder turns, it gets pushed up, no big deal. The only reason the key works both ways is that it's flushed all the way across.

 lock cylinder

The following key I pulled can only turn to the right. As you can see, all four middle pins are flush; however, the first and last pins are not flush to the top. So, what happens is that the grooves will allow the cylinder to turn to the right. And the reason it's going to let it is because there's a place for the top pins to escape. When you start to turn the key since it's flush here, it'll turn, and then on each end, when you turn it, these top pins will have an escape. They have a way out. However, if you were to turn it to the left, it won't because the top pin is on top of the bottom pins, and there's no escape like the other side. It's like when you put a standard key into a lock that doesn't fit. It will not turn. And that's how it's only turning one way in the lock.

 locksmith tips

Now, for the other key that can only turn to the left. As you can see, the 2nd and 4th pins are not flush. Once again, they have an escape on the side, which will allow the key to turn to the left, but they're not going to turn to the right because the top pin will stop it.


One of the reasons I like this so much is that it breaks my thinking a little bit. There are some practical applications. Like Greg had said, he uses it in a gas station setting where someone can only have the ability to turn the key one way to lock the door, but they can't unlock it. There are some real-world use applications for this. However, there are some security problems as well because as soon as you start putting those slots in that plug, it becomes very easy to manipulate all of a sudden. However, I believe that the more tips and tricks that we can keep in our back pocket when the situation arises, the more we can get the job done. I would love to know in the comments below what you think? Are there situations where you can see yourself using this or because of security issues? It's just something that you would not do. Thank you, and we'll see you next time.

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