Door Chain Locks

admin  —  October 11, 2019 — Leave a comment


At the risk of insulting your intelligence, it is important to know that a chain is a serial assembly of connected pieces that are commonly called links. A chain is usually made of metal but can be made of bamboo, rope and wire. It is usually flexible and a length of linear material that can bear up under tension and hold a load.

The links within a chain are usually fixed in dimensions and shaped in such a way that tension can be placed throughout the length of the link and consequently the entire chain itself.

Chains may be used for a variety of purposes.

They may be used for decoration such as a piece of jewelry, a chain of office worn around the neck and upper torso, decoration for clothing, and may be mounted on a backing. Chains may also be used for the transfer of power such as timing chains in automobiles, chainsaws, bicycles, chain drives, and chain pumps. The ball and chain has long been a form or restraint and chains have been used for security purposes. Chains may also be used for traction and pulling. Some weapons in military applications were made of chains.


Mechanical locks appeared in the human experience about six thousand years ago in Egypt. They were made of wood and consisted of a wooden post affixed to a door and a horizontal bolt that slid into the post.

The English are credited with forging and creating the first metal locks.

Door Chain Locks

A door chain is also known as a security chain or a security door chain. It is a small chain attached to a door frame that is then attached to a track for security. They are usually not the primary lock on the door but are used in conjunction with keyed locks and dead bolts to add an extra degree of security.

A door chain lock allows a person to open the door slightly without unlocking the door. It is also possible to communicate with the person outside the door before allowing them entry. Small packages, letters or notes may also be passed through the door opening.

Door chain locks are easy to install requiring a screwdriver and possibly a drill gun for the drilling of pilot holes. If there are any downsides to door chain locks it is the fact that they are usually installed with short screws that can be pulled out of wooden frames. Another potential negative about this kind of lock and chain mechanism is that it is usually a small chain that require some degree of manipulation by human hands to use. The elderly or anyone with a central nervous system disorder causing tremors may find it difficult to place the end of the chain in the track. In regard to the track, it is straight and it is not hard to separate the chain from the track. Door chains may also be broken if forced and torque are applied appropriately.

Sometimes the best option is to go with a door bar that gives you a U-shaped bar that attaches to a hinge and a knob on the door. A door bar is easier to use for any physically challenged person and are more sturdy than a chain.

Consult with your locksmith to determine which is best for your situation.

If you decide you want to use a door chain lock and want to tackle the job of installation, here are some steps to take.

1. Go to a hardware store or your local big box store and see what they have. You might want to read about this device on the internet before shopping for it or you can consult with your locksmith to see what you need to purchase. Do yourself a favor and choose a door chain lock that comes with a template.

2. Get the tools you need. This will be a good drill with a bit that is smaller than the size of the screws. You will want to have a correctly sized screwdriver to get the screws down into your wooden door frame.

3. Remove the template from the packaging and tape it to the spot you want to place the door chain lock. You will want to place the lock approximately 3 to 6 inches above the deadbolt or the same distance above the door handle.

4. Using the template make the marks where the door chain lock will go. After making the marks, the template may be set aside.

5. Pre-drill the holes for the screws that came in the package. Drill the holes keeping the drill completely vertical and at right angles to the surface of the door. This will ensure maximum hold as the screws will be as deep as possible in the wood.

6. Now you can attach the lock plate using the screws supplied.

7. The next step is to tape the chain mount template to the wall. It should be positioned just outside the door frame and should line up with the lock plate.

8. Mark this template as you did before with the lock plate template.

9. Pre-drill the holes for the chain mount.

10. Use the screws provided and screw in the chain mount.

Try your work. Attach the chain to the straight slot and see if it holds. Check your handywork and make sure you are convinced it will all hold correctly and in a secure fashion. The door should not open more than an inch.

mark burns belfast

As always, if you are not comfortable with this kind of installation or if you have any other security concerns, feel free to contact me.

I’m Mark and I can be reached at 07866522422

Or email me!




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