Everything You Need to Know About Interchangeable Core Locks

Key Takeaway

  • Interchangeable core locks are a type of lock system that allows for the easy removal and replacement of the lock core without having to replace the entire lock. 
  • Interchangeable core locks offer greater flexibility, cost-effectiveness, and convenience compared to traditional lock systems. 
  • Full-size interchangeable core locks are typically used in high-security commercial and institutional applications. In contrast, small-format interchangeable core locks are more commonly used in residential and lower-security commercial applications.

As someone who has always been interested in the world of locks and security, I was thrilled to discover the innovative technology behind interchangeable core locks. These locks offer a unique solution to the age-old problem of balancing convenience and security by allowing for the easy removal and replacement of the lock core without having to replace the entire lock.

But with any new technology comes questions and concerns. How do interchangeable core locks differ from traditional lock systems? How do they work? And most importantly, are they really worth the investment?

What Are Interchangeable Core Locks, And How Do They Work?

Have you ever found yourself in a situation where you needed to change the key to your lock but didn’t want to replace the entire lock? That’s where interchangeable core locks come in! My friend recently took a warehouse on rent for his business, and I helped him with an interchangeable core lock for enhanced security. These types of locks allow you to easily change the key without having to replace the entire lock. 

While rekeying locks is another way, the key control of a lock can be changed. Interchangeable core locks offer greater flexibility, key control, and security compared to rekeying. They can be swapped out quickly and easily, offer enhanced security features, and can be cost-effective in the long run. Rekeying may be a more cost-effective option in some cases, but interchangeable core locks are a more practical choice for properties that require greater customization and security.

The interchangeable core locks consist of two separate components: the core and the lock body.

What Are Interchangeable Core Locks, And How Do They Work?

The core is a small cylinder that contains the keyway and can be easily removed from the lock body. This core can be replaced with a different core, allowing you to change the key without having to replace the entire lock.

Here’s how,

  • Remove the existing cylinder: Using a control key, turn the cylinder 15 degrees in either direction to unlock it. Once the cylinder is unlocked, use a cylinder removal tool to push the clip or pin on the back of the cylinder, which will release it from the lock housing.
  • Install the new cylinder: Insert the new cylinder into the lock housing and use the control key to turn it 15 degrees to lock it into place.
  • Program the new cylinder: If necessary, program the new cylinder with the appropriate key codes and master key codes.
Program the new cylinder

Applications of Interchangeable Core Locks

Interchangeable core locks have many applications in residential, commercial, and industrial settings. Here are a few examples:

  • Interchangeable core locks are a great option for securing residential properties. They are also ideal for vacation homes or rental properties, where frequent rekeying may be necessary.
  • In commercial buildings, such as offices, warehouses, and factories, interchangeable locks offer the flexibility to provide access to different areas of the building for different employees while still maintaining overall security.
  • Interchangeable core locks are also widely used in educational institutions, such as schools and universities.
  • Interchangeable core locks are also ideal for healthcare facilities, such as hospitals and clinics.
  • Retail stores often use interchangeable core locks to secure inventory rooms and storage areas. 
  • Banks and other financial institutions also use interchangeable core locks as they allow quick and easy rekeying, which is essential in the event of a security breach.
  • Interchangeable core locks are also commonly used in government buildings, such as courthouses and city halls. 

Advantages of Interchangeable Core Locks

Interchangeable core locks have several advantages over traditional locks. Some of those are mentioned below.

  • Easy Key Replacement: One of the most significant advantages of interchangeable core locks is their ability to allow you to replace the key easily. With just a few simple steps, you can swap out the old core for a new one, ensuring that only authorized personnel have access to your property.
  • Enhanced Security: Interchangeable core locks offer enhanced security features, such as the ability to rekey the lock when keys are lost or stolen easily. This means that you can quickly and efficiently update the lock to prevent unauthorized access to your property.
  • Cost-Effective: Interchangeable core locks are a cost-effective solution for your security needs. Instead of replacing the entire lock, you only need to change the core, which is significantly cheaper. This is especially useful in situations where you need to rekey locks frequently.
  • Customizable: Interchangeable core locks offer customization and flexibility, allowing you to tailor the locks to meet specific security needs. For example, you can use master keys to provide access to authorized personnel while limiting access to others.
  • Versatile Application: Interchangeable core locks are suitable for a wide variety of applications, including residential and commercial buildings, educational institutions, healthcare facilities, retail stores, and banks. They are particularly useful in environments where frequent rekeying is necessary or where there is a need for different levels of access.
  • Durable: Interchangeable core locks are typically made of high-quality materials such as brass, stainless steel, or nickel-silver. The cores themselves are usually made of brass or steel. These materials are chosen for their durability, resistance to wear and tear, and ability to withstand harsh environmental conditions.

Types of Interchangeable Core Locks

There are two main types of interchangeable core locks: Full-size interchangeable core locks and Small-format interchangeable core locks.

Full-Size Interchangeable Core Locks

Full-Size Interchangeable Core Locks

Full-size interchangeable core locks (also known as “large-format interchangeable core locks” or “FSIC”) are typically found in commercial and institutional applications and are characterized by their large, bulky design. These locks are typically used in high-traffic areas such as hospitals, universities, and government buildings.

Full-size interchangeable core locks use a cylinder that is larger than that of a standard lock, with a diameter of around 1.5 inches. The keyway is also larger, with a cross-shaped profile. This allows for greater flexibility in keying options and increased security due to the more complex key profile.

One of the main advantages of full-size interchangeable core locks is their durability. These locks are designed to withstand heavy use and are often constructed with high-quality materials such as hardened steel or brass. They are also resistant to picking and other forms of forced entry, making them ideal for high-security applications.

You can buy an FSIC for your security needs online at The Builders Supply, Zen Supply, Craftmaster Hardware Store, etc.

Small-Format Interchangeable Core Locks

Small-Format Interchangeable Core Locks

Small-format interchangeable core locks (also known as “SFIC locks”) are a more compact version of the interchangeable core lock and are typically used in residential and commercial applications where a lower level of security is required. These locks are also commonly used in furniture and cabinet locks.

SFIC locks use a smaller cylinder than full-size interchangeable core locks, with a diameter of around 0.6 inches. The keyway is also smaller, with a figure-eight profile. Despite their smaller size, SFIC locks still offer a high level of flexibility in keying options and can be easily rekeyed without the need for special tools or equipment.

One advantage of SFIC locks is their versatility. They can be used in a wide range of applications, from residential door locks to filing cabinets and desk drawers. They are also relatively easy to install and maintain, making them a popular choice for homeowners and small business owners.

SFICs can be bought online on Allegion, Amazon, Craftmaster Hardware Store, etc.

Frequently Asked Questions

Q1. Which is more expensive-Full-Size Interchangeable Core Locks or Small-Format Interchangeable Core Locks?

Answer – Full-Size Interchangeable Core (FSIC) locks are typically more expensive than Small-Format Interchangeable Core (SFIC) locks as FSIC locks are used for larger-scale applications and have higher security requirements, while SFIC locks are used for smaller-scale applications and are less expensive due to their simpler design. The price range for interchangeable locks can vary widely depending on the brand, level of security, and other features. Generally, you can expect to pay anywhere from $100 to $500 or more for a single FSIC lock. SFIC locks, on the other hand, are generally more affordable than FSIC locks. The price range for SFIC locks is typically between $50 and $250 per lock.

Q2. How do interchangeable lock cores differ from traditional lock systems?

Answer – Interchangeable lock cores differ from traditional lock systems in that they allow for the lock cores to be removed and replaced without having to replace the entire lock. Traditional lock systems require the entire lock to be replaced if the key is lost or the lock needs to be rekeyed, which can be time-consuming and expensive.

Q3. Is maintaining interchangeable core locks challenging?

Answer – Maintaining interchangeable core locks involves similar steps to maintaining other locks, such as regular cleaning, lubrication, inspection for wear and tear, and testing for proper functionality.


Interchangeable core locks are a game-changer in the world of lock technology, providing a cost-effective and versatile solution to enhance the security and convenience of homes and businesses. In this blog post, we have explored the basics of what interchangeable core locks are, how they differ from traditional lock systems, and what factors to consider when selecting and installing them.

We have seen that interchangeable core locks offer many benefits, such as flexibility, ease of use, and cost-effectiveness. I hope the article must have provided you with all the information about interchangeable core locks that you are looking for. For any other assistance, write to me in the comment section. I shall be happy to help!

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Hey! I am Mark. Though I am not a locksmith by profession, but locks have always fascinated me since my teens. And it all started when I got locked out of my house and I had to pick the lock. Since then it has become my hobby to learn more about different kinds of locks, understand their working and methods to pick them up. In due course of time, I have also become better aware of how installing the right lock goes a long way in ensuring iron clad security. I aim to share my passion (about locks) through this blog. If you are also passionate about picking locks or are just looking to beef up the security, hop on the ride.