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Locksmithing 101 | How to INCREASE the Security on Mortise Cylinders

Aside from your locksmithing skills, you should have the necessary tools to complete the job. I will show you how to quickly improve a mortise cylinder's security on an aluminum storefront door, but first, take a look at this Major CAK-15 Cylinder Accessory Kit. When you come across an aluminum storefront-style door, having one will be a game-changer. Major CAK-15 Cylinder Accessory Kit has a whole bunch assortment of colors and a few cylinder guards to get started.

CAK-15 Cylinder Accessory Kit


Mortise cylinders are a little more susceptible to getting broken, so better be careful dealing with it.

Remove the plate first, then back off the small set screw, three or four turns. The mortise cylinder is held in place by these screws. After that, half-turn the key and begin to undo it. Here is a link to a video that will show you how to remove the cylinder and replace it without damaging it.

But essentially, get it to a spot where you can take the mortise cylinder out with tease.

Mortise Cylinder removal

So, when you take a cylinder out, the tiny set screw that you loosen goes right to the groove and holds the cylinder in place. Securing it from being unscrewed and essentially from breaking.

Mortise Cylinder


In theory, someone could take a big pipe wrench or something and put it on this cylinder and snap that off, bypass it and get in, and a way around that is to use cylinder guards. Major and Keedex are makers of it, and both are great products.

Open the package, get the wave washer, and then the cylinder guard. Put it together to the mortise that you've taken off, but it is better to move to an inch and an eighth mortise cylinder, which is longer.

Mortise Cylinders

Because if you take the ring that came standard with the door and screws it back on, you'll have a significant gap, which is a problem. Under no circumstances should a door be left looking like that. You have two choices in this situation: you can use a cylinder guard or a thicker collar.

Installing guards on mortise cylinder


But back to the security part of it, let's go and put a cylinder guard on, and show you how that works. Get the mortise cylinder, put this wave washer, as you can see, it makes up for a lot of distance because of the tension, and then drop our cylinder guard.

Installing mortise cylinder

So, once you have it together, all you have to do is screw it back. You can notice that the cylinder guard should be able to spin freely, and the face of the cylinder should not be sticking out over it.

Locksmith tips - Increase security on your mortise cylinder

Now one thing you want to consider is the size of the keys. So some guys like to have the cylinder buried way back there, which is perfectly fine. But you want to make sure that there must be enough clearance when you're sticking the key.

I think typically having a gap there is an excellent spot to be. However, you're going to be just doing what you're working with, doing the best you can do, but that's what it should look like, and so now if someone were to stick a pipe wrench on here, that's just going to spin and not the actual mortise cylinder. Seal it by tightening the set screw again.

Tighten all screws on the lock

And that's how you can use a cylinder guard to increase a mortise cylinder's security on an aluminum storefront door. I'd love to know your thoughts; feel free to reach and raise your questions in the comments below! 

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