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Locksmithing 101 The 3 Most Popular Types of Tail Pieces for SFIC Cylinders

If you deal with Small Format Interchangeable Core Locks, or SFIC for short, you'll almost certainly find yourself in a situation where you have the cores, the locks, but not the tailpiece that links the two. The good news is that I'll teach you how to use the three most popular SFIC tailpieces available today. Now, I'm going to use the 80/20 concept again, where I'll show you the three most popular that will account for 80% of the market, but there will still be a few oddballs out there. Hopefully, you'll be able to change these tailpieces to match since I'll also add a bonus tip to help you get out of a jam.


Look on the 6 and 7 pin cores before we get going. The one on the right is the six-pin, and the other one on the left is the seven-pin. The difference in length between the two is essential when it comes to finding a suitable tailpiece. Because if the tailpiece is either too long or not long enough, it's not going to go in the lock and work properly.

Now that we have that let's talk about the three tailpieces. These are the standard flat tailpieces. Now, there's one for six pins and one for seven pins. When I line them up next to each other, you're going to see that the seven-pin is shorter than the six pins. It is because the seven pins, the seven pins core is longer. The seven-pin tailpiece is shorter than the six because it doesn't need to go as far to get into the lock. These are going to be by far the most popular tailpieces, just the standard sizes.

Now, you may have to depend on the lock you're working on. You could have to modify these a little bit to work. Still, in my experience, these two right here are going to cover just about everything you need as far as flat tailpieces, so essentially, you take the seven-pin, take the seven-pin core. You stick it in the back just like that, so it's just going to go loose in there, it just sits in just like that and then same with the six-pin, that's going to go in just like that, and then you're going to be done, so that's simple, that's how these two work.


The other one I want to talk about is what is referred to as the twist tailpiece. I mean that if I were to take this core here and put this in, the prongs here going into the lock or horizontal. Then the tailpiece here is vertical, so you will find yourself in situations where you need these. Now, this is a reinforced one.

You'll see a lot of them that are just kind of like this, and they have like a twist in them, they're putting the machine, and they were twisted, and from everything I've ever seen or dealt with, they don't last.

The reinforced ones are the ones that I would love to see how it was made because it's fascinating what they did. It is like a more reinforced one that will last much longer when you need that.


Now, the question is, what happens if you don't have the correct length tailpiece? And this is where the tip comes in.

Let's say you have a six-pin core, and all you have is like a seven-pin tailpiece or a tailpiece that when you put it in, and you put it in the door, and it just turns, and it's not operating the lock, that tells you it's not going to be long enough. By easy, simple fix, if you don't have any other tailpieces, take your standard universal top pins.

This is like a 150. You can even use a Kwikset or a Schlage top pin. Anything with a .115 diameter and all you must do is stick it right in the back here. Look, they fit perfectly.

By doing that, you can take a seven-pin tailpiece or a shorter tailpiece, and you can stack it out as high as you need to make it to go into the lock and operate it, so that's a nice little tip for you.

Always want to keep that in your back pocket and then just come out just like that, pleasant and straightforward, so these are the three tailpieces that you're going to find out there that you're going to want to make sure you have available.

Alright, and there you have it - the three most common SFIC tailpieces on the market today and then. Also, keep in mind if you ever need to extend those tailpieces, using the universal top pins is a great way to get that extra link when you need it. I'd love to know your thoughts in the comments below. Thank you, and we'll see you next time!

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