In our last blog post we explored the very beginnings of locks, from proto-locks made from rope, to the first mechanical locks made of wood. To no one’s surprise, the technology behind mechanical locks has flourished in the intervening centuries. In the first of a multi-part series, we will begin to explore some of the most fundamental lock technologies that have led to the secure locks you can find today. Be sure to contact the professionals here at Pro-Lock & Safe for all of your safe locksmith needs in the Felton area.

In this post we will be looking at some of the most popular locks and their common variations. We have also briefly explored common house locks in a previous blog post. This post will include an overview of padlocks and deadbolts. The next post in the series will look at handle locks and furniture locks.


The padlocks are a classic lock. For many of us, the word “lock” conjures in our minds a picture of a single-dial padlock. They are convenient, portable, and offer a reasonable degree of safety (though, as we will see below, perhaps not as much as we would hope). But not all padlocks are created equal. Below we will explore the two major varieties of padlock.

Combination Padlock

Ah, the classic combination padlock: a nostalgia-laden lock that transports many of us right back to our teenage years. What’s a more iconic representation of the hallowed high school hallways than the classic stainless steel combination padlock? These single-dial combination padlocks kept our binders and biology textbooks safe and sound — though they are not generally recommended by safe locksmiths for much more than this, as they are relatively easy to pick.

The single-dial padlocks — the ones most associated with securing lockers — require a specific sequence of numbers in order to be unlocked. These are also commonplace on many kinds of safes. However, there are also multi-dial combination padlocks that you might recognize from bike locks or locks on briefcases. These multi-lock padlocks are generally considered even less safe and less reliable than their (already easily-cracked) single-dial counterparts, and would therefore not come highly recommended by a safe locksmith.

The combination padlock may evoke memories of childhood, but their history goes back much further than that. The padlock was invented in 1857 — two years before Darwin published On the Origin of Species.

Key-Based Padlock

The key-based cousin of the combination padlock is generally considered to be a bit more secure. However, there are some important considerations before choosing a key-based padlock.

First off, the key-based padlock unsurprisingly involves the use of a key. For certain key-based padlocks, they cannot be rekeyed. This means that if you were to lose the key, the lock becomes useless and you will have to have your local safe locksmith remove it. Other types can be rekeyed. Another variety of the key-based padlock requires the key to remain in the lock while it’s open. These are known as key-retaining padlocks.

There is also a variety of padlock that is somewhat intermediate between the combination and key-based padlock. These are sometimes known as TSA-approved padlocks, and they typically involve a number combination as well as key access. The Transportation Security Administration will have access to “Master Keys” that will be able to unlock all TSA-approved padlocks. While these locks are meant to be useful for luggage during travel, it seems that they have proven to be exceptionally easy to crack and are therefore not the best option to protect your valuables.


Deadbolts are generally considered a very safe option for home security. We have even explored the importance of having a deadbolt in your home. A deadbolt is not considered a typical lock because there is no spring. The deadbolt is considered a safer option than standard spring locks because they require a key to open all the way, and are therefore harder to pick. These are commonplace on the exterior of homes and heavy-duty hotel doors. Deadbolts generally require that they be drilled and installed directly into the door itself, though there are exceptions (as you will find out about below). There are three primary versions of the classic deadbolt.

Single and Double Cylinder

Single cylinder deadbolts are commonplace in homes. These are the locks that you recognize as requiring a single turn with a key from the outside or a single thumbturn on the inside.

Double cylinder deadbolts are less common, but they are generally considered even safer. These require the use of a key from both the inside and the outside. Although considered safer, they also present potential safety hazards and are even outlawed in certain areas of the U.S.

Lockable Thumbturn Style

Lockable thumbturn style locks are a combination of the single and double cylinder deadbolts. They are generally considered the gold-standard of home safety. The lockable thumbturn style deadbolt allows for the homeowner or business-owner to essentially choose between the standard single cylinder lock with the cylinder on the outside and the extra safety of the double cylinder requiring a lock from both ends.

Jimmy-Proof Deadbolt

Finally, you have the jimmy-proof deadbolt. These are deadbolts that, unlike the deadbolts mentioned above, are installed on the surface of the door, meaning they don’t require much in the way of altering the door itself before installation. These are commonplace in apartment buildings. They offer a good deal of safety and are able to hold up to a strong amount of force, even more so than the standard deadbolt.

The Safe Locksmiths at Pro-Lock & Safe

The above locks only scratch the surface of all the varieties of locks out there. However, the ones we went over today include some of the most popular locks, the types of locks that you have undoubtedly come across many times in your life. We will continue to look at more locks in the next part of this series. In the meantime, reach out to Pro-Lock & Safe for any of your locksmith questions. We offer top-notch safe locksmith services in the Felton area, and we are ready to help you today.