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CHU3K74080PB
Union 3K74E 5 Lever Sashlock 80mm Brass BS3621 (Chubb At Heart)
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Union (Chubb At Heart) B-3K74E 80mm Brass 5 Lever Bs Mortice Lock 2K
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Delivery Information
| Delivery Time Frame | Delivery Information |
| Next Working Day By 1PM | When an order is placed by 3pm for next working day on certain items |
| Standard Delivery | Usually delivered in 2 to 4 working days |
| Delivery Charges | |
| UK Mainland | Prices start at £3.95 for very small items, £6.50 for small, £9.50 for medium and £20 for large/long items |
| Scottish Highlands & Islands, Northern Ireland & Ireland | Prices from £30, please see our delivery page for more info. |
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£95.88
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£79.90
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Description
Union 3K74E 5 Lever Sashlock 80mm Brass BS3621 (Chubb At Heart)
When it comes to protecting your property, the hardware you choose acts as the primary line of defence. The Union 3K74E 5 Lever Sashlock 80mm Brass BS3621 represents the gold standard in mortice lock technology. Often referred to as the Chubb at heart, this lock combines legacy engineering with modern security requirements to offer unparalleled peace of mind for residential and commercial premises alike.
This sophisticated locking mechanism is designed for timber doors that require a high level of protection against forced entry. Whether you are upgrading your home security to meet insurance standards or fitting out a new commercial office space, this model provides the robust reliability necessary to deter intruders effectively.
Unrivalled Security and Compliance
Security is not merely about having a lock on your door, it is about having a system that resists the most common methods of attack. This item has been rigorously tested and holds the BS3621:2007 certification, which is the benchmark for thief-resistant locks in the United Kingdom.
- This hardware has been approved by major insurance companies, ensuring that your home contents policy remains valid and your premiums are optimised.
- The unit is proudly Secured by Design approved, meaning it is officially recommended by the Police for its superior resistance to physical tampering.
- The integration of anti-drill, anti-pick, and anti-saw security features ensures that even experienced intruders will find this lock incredibly difficult to bypass.
- An extended 20mm deadbolt provides a deep throw into the door frame, which creates a positive locking action that resists side-load pressure and physical impact.
Mechanical Physics and Structural Integrity
The internal mechanics of this sashlock are built to withstand significant stress and torque. When the key is turned, the five-lever mechanism engages with precision, ensuring that the bolt is driven into the strike plate with maximum force. This movement relies on high-quality internal components that prevent the common failure points found in cheaper, mass-produced alternatives.
The hardened steel rollers embedded within the deadbolt serve a crucial protective function. If an attacker attempts to use a hacksaw to cut through the bolt, the rollers spin freely, preventing the blade from gaining purchase. This simple yet effective physical principle significantly increases the time required for a forced entry, often acting as a sufficient deterrent to make a burglar abandon their attempt entirely.
Furthermore, the sintered iron follower provides the necessary structural rigidity to handle repeated use without succumbing to metal fatigue. The internal spring tension is calibrated to provide a smooth, tactile experience for the user while maintaining enough resistance to keep the mechanism securely in the desired position.
Operational Workflow for the User
Using this lock is an intuitive process that feels both secure and reliable. When you approach your door, inserting the key into the escutcheon allows you to engage or retract the deadbolt with a smooth, consistent motion. The internal levers align with the bitting of the key, creating a satisfying mechanical engagement that confirms the lock is functioning as intended.
For daily operation, the roller bolt is designed to be withdrawn by the lever handle from either side. This allows for quick egress or entry without needing to lock the door every time you step out. The non-handed nature of the roller bolt means that the door can be set up to swing in either direction, simplifying the installation process for joiners and locksmiths significantly.
When leaving the property, the user simply pulls the door shut, engages the lever handle to ensure the latch is secure, and then uses the key to throw the deadbolt. This two-stage process ensures that the door is not only held shut by the spring latch but is physically bolted into the door frame, providing maximum security against external force.
Ergonomic Health and Security Compliance
High-quality hardware is not just about security, it is also about the ease of interaction for the end user. A poorly manufactured lock can become stiff or difficult to turn, leading to physical strain or frustration. This model is engineered with precision tolerances that ensure the key turns effortlessly, reducing the potential for wrist strain or repetitive motion injuries.
In a commercial environment, ensuring that all doors meet fire and safety standards is a legal requirement. By installing a lock that is fully compliant with modern building regulations, facility managers reduce their liability and ensure that all staff and visitors are protected by the highest standard of hardware. This level of compliance also simplifies the insurance renewal process, as the certification is widely recognised by risk assessors.
Commercial ROI and Long Term Value
While some may view the initial purchase price of a premium lock as an expense, it is more accurately defined as a long-term investment. Cheaper locks often require replacement within a few years due to internal component failure or oxidation. This model is built to last, backed by a 25-year guarantee that speaks to the quality of the brass and steel materials used in its construction.
By reducing the frequency of maintenance and replacement cycles, businesses and homeowners can significantly lower their operational overheads. Protecting assets from theft also avoids the catastrophic costs associated with burglary, such as insurance excess payments, loss of proprietary data, and the emotional stress of a security breach. Choosing high-quality components is a proactive strategy for asset protection.
Technical Specifications
The following table provides a comprehensive overview of the dimensions and technical capabilities of this lock. Please ensure these measurements align with your door requirements before purchase.
| Feature | Specification |
|---|---|
| Case Size | 80mm (3 inches) |
| Backset | 53mm |
| Faceplate Dimensions | 153mm x 25mm |
| Case Height | 108mm |
| Centres | 57mm |
| Material | Steel case with polished brass forend |
| Keys Supplied | 3 keys included |
| Standards | BS3621:2007 and CE Marked |
Not sure if this mortice lock is right for your requirements? If you are not sure if this mortice lock is right for your requirements please contact our friendly team today.
The finish on this lock is a classic polished brass, which provides a timeless aesthetic that suits both traditional and contemporary door styles. The included escutcheon plates are finished to match the faceplate, ensuring a cohesive and professional look once installed. The steel case is treated with a silver powder coat, providing an additional layer of protection against corrosion and environmental wear.
Whether you are a professional locksmith or a DIY enthusiast, the clear dimensions and high-quality build of this product make it an excellent choice for a wide range of applications. Its ability to perform under pressure, combined with its insurance-approved credentials, makes it a standout option in the current market. If you require further assistance or have specific questions regarding compatibility, please reach out to our team at Doorfit for expert guidance.
Specification
| Manufacturer | Union |
|---|---|
| Dimensions | 108 (H) x 80 (D) |
| Guarantee | 25 Year |
| Lock Type | Mortice Sashlock |
| Lock Operation | Lever |
| Lock Backset | 53mm |
| Lock Centres | 57mm |
| Follower Size (mm) | 8 |
| Faceplate Width | 25mm |
| Environmental Suitability | All |
| Mechanism | Sashlock |
| Door Material Suitability | Wood |
| Max Door Thickness (mm) | 50 |
| Forend Finish | Polished Brass |
| Security Standards | BS3621:2007 |