What is the difference between a 3 lever and a 5 lever deadlock?

A 3 lever deadlock provides medium security suited to internal doors. A 5 lever deadlock provides higher security and is typically the preferred choice for external doors and insurance-led requirements.

Can a 3 lever mortice deadlock be used externally?

It is not generally recommended because 3 lever locks typically do not meet insurance expectations for external doors. A higher security 5 lever deadlock is usually the better option.

What sizes do 3 lever mortice deadlocks come in?

Common case sizes are 64 mm (2.5") and 76 mm (3"), selected to suit door thickness and handle/escutcheon positioning.

Do I need an escutcheon with a 3 lever mortice deadlock?

Yes, most installations use a standard keyhole escutcheon to protect the door surface and give a neat finish. Choose an escutcheon that matches your door furniture and finish.

Are 3 lever deadlocks suitable for fire doors?

They can be used on some fire door setups, but you should only choose a lock that is specifically fire-rated/certified for the door and follow the door manufacturer’s guidance (often including the correct intumescent pack where required).

Standard Mortice Key 3 Lever Deadlocks

Standard Mortice Key 3 Lever Deadlocks for Internal Wooden Doors

Protect bedrooms, offices, and connecting rooms with our standard mortice key 3 lever deadlocks. These key-operated deadbolts sit flush in the door edge for a clean look and smooth, reliable security on internal timber doors.

What is a 3 Lever Mortice Deadlock?

A 3 lever mortice deadlock fits into a machined pocket in the door edge and throws a solid deadbolt into the frame. It’s ideal for medium security on internal doors and pairs neatly with standard profile escutcheons and coordinated door furniture.

Sizes, Finishes & Related Ranges

Choose common case sizes 64 mm (2.5") or 76 mm (3") to suit door thickness and handle positioning. Match finishes like polished brass, satin chrome, or black to your scheme. Explore the wider Standard Mortice Key Locks family including deadlocks and sash locks. For higher external security, see 5 lever deadlocks. Delivery available to London, Manchester, Birmingham, and across the UK.

More hardware to complete your project: Architectural Ironmongery, Window Furniture, Accessories.

Atlantic 3 Lever Key Deadlock CE 3inch - Antique Brass

Secure & Practical Internal Door Locks

Why Choose a 3 Lever Mortice Deadlock?

A 3 lever mortice deadlock is perfect for bedrooms, offices, storage cupboards, and internal connecting doors where a balance of security and convenience is needed. Unlike surface-mounted locks, mortice deadlocks sit flush inside the door, making them both discreet and tamper-resistant. They are lighter than external-grade locks, making them affordable and easy to operate, yet still robust enough for regular use. For a complete internal door setup, match with door furniture and standard profile escutcheons.

Need Expert Advice?

Get the Right Lock First Time

We can help you choose between a lighter 3 lever lock for internal doors or a high-security BS3621-approved model for external entrances. See related products: 3 Lever Mortice Deadlocks, 5 Lever Mortice Deadlocks, and Sash Locks.

If you can’t find what you need, contact us and we’ll help source the perfect lock for your project.

Frequently Asked Questions

Do these locks work with any escutcheon?

Yes – they are designed to work with most standard keyhole escutcheons.

Are they easy to fit?

With the right tools, fitting is straightforward, especially for those familiar with mortice lock installation.

Nationwide Supply & Trusted Brands

Security Hardware You Can Rely On

We supply mortice deadlocks UK-wide, covering London, Manchester, Birmingham, Leeds, Glasgow, Cardiff, and more. All products are chosen for durability, smooth operation, and compatibility with British door standards.

Popular brands include From The Anvil, Carlisle Brass, Heritage Brass, and Frelan Hardware. Complete your project with matching door furniture and standard profile escutcheons for a coordinated finish.