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CHU3K70073SC
Union 3K70 5 Detainer Sashlock 73mm Satin (Chubb At Heart)
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Union (Chubb At Heart) B-3K70 73mm Satin 5 Detainer Mortice Lock 2K
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| 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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£274.97
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£229.14
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£190.80
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£159.00
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Description
Union 3K70 5 Detainer Sashlock 73mm Satin (Chubb At Heart)
Choosing the right locking mechanism for your timber doors is a decision that impacts the fundamental safety of your property. The Union 3K70 5 Detainer Sashlock 73mm Satin (Chubb At Heart) represents a heritage design that continues to lead the market in reliability and mechanical integrity. Known for its sophisticated detainer technology, this hardware provides an elevated level of protection compared to traditional lever mortice locks.
Engineered for high-traffic environments, this unit delivers a smooth operation that users feel the moment they turn the key. Its satin chrome plated finish offers a modern aesthetic, ensuring that the hardware complements contemporary door furniture while resisting the wear associated with daily use. Whether you are upgrading a residential entrance or securing office spaces, this model is a masterclass in functional security.
Unrivalled Mechanical Engineering and Physics
The internal mechanism of this product is designed to handle significant mechanical stress through precise physical interaction. When the key enters the cylinder, it engages the detainer discs, which must be aligned with extreme accuracy to allow the fence to drop into the gate. This movement requires a precise degree of torque, which the brass deadbolt manages with ease.
The inclusion of hardened steel rollers within the bolt is a specific engineering choice to mitigate the risk of sawing attacks. By allowing the surface of the bolt to rotate upon contact with a blade, the physical force of a hacksaw is dissipated effectively. This structural reinforcement ensures that the lock retains its integrity even under sustained pressure, providing peace of mind for property owners who value long-term resilience.
The sintered iron follower contributes to the internal stability of the latching mechanism. Because sintered metal provides superior wear resistance compared to standard cast iron, the interaction between the handle and the latch remains fluid over many years. This reduces internal friction and prevents the metal fatigue that often plagues cheaper alternatives.
Operational Workflow for Daily Security
Interacting with this locking system is an intuitive process that prioritises ease of use for the end-user. When you approach the door, the latch bolt is naturally extended to keep the door held in place against the frame. By depressing the lever handle, the user applies a controlled force to the sintered iron follower, which retracts the latch bolt against the internal spring tension.
The transition from a latched state to a locked state occurs via the key. Inserting the key into the five-detainer core allows the user to rotate the mechanism, projecting the 14mm brass deadbolt into the box strike. The tactile feedback during this process is firm and reassuring, signalling to the user that the locking pins have correctly seated in the frame. Unlocking involves the reverse movement, requiring an equally controlled rotation that ensures the deadbolt clears the striking plate completely before the door is opened.
Ergonomics and Safety Compliance
Modern security hardware must balance high-level protection with user health and safety. This model features a design that minimises the force required to engage the mechanism, which is critical for inclusivity and accessibility. By reducing the physical effort needed to lock and unlock a door, this item ensures that all users, regardless of physical strength, can operate the security system with ease.
Compliance with fire safety standards is non-negotiable for commercial and residential installations. This product has been EN 1634-1 assessed for use on 60 minute timber fire doors. This means the lock is constructed to maintain its shape and functionality during the intense thermal expansion that occurs in fire conditions, ensuring that exit routes remain secure yet accessible for emergency egress.
Expert Insight If you are not sure if this mortice lock is right for your requirements please contact our friendly team today for professional advice on compatibility and installation standards.
Commercial ROI and Long Term Value
Investing in premium security hardware is a strategic decision for any property manager. While lower-cost alternatives might seem attractive initially, the total cost of ownership over a ten-year period tells a different story. This high quality hardware is designed to withstand thousands of operational cycles without significant loss of tolerance or mechanical precision.
- The durable brass components and hardened steel rollers minimise the need for frequent maintenance or costly emergency locksmith call-outs.
- The 10 Year Guarantee serves as a testament to the build quality and provides financial protection against manufacturing defects over the long lifespan of the product.
- By choosing a robust detainer system, you reduce the risk of asset loss due to lock picking or brute force entry, which can be far more expensive than the initial purchase price of the hardware.
- Standardising your door hardware across a site creates an efficient maintenance programme, as replacement parts and striking plates remain consistent throughout the facility.
Versatility in Application
This model is designed to be highly versatile, making it an excellent choice for a variety of timber doors. It works effectively for doors hinged on either the left or the right, providing flexibility during the installation phase. The 73mm case size is an industry standard that allows for straightforward retrofitting in many existing door configurations, while the 44mm backset ensures that the key operation remains clear of the door handle, preventing finger trapping or operational interference.
Technical Specifications
The following table details the core dimensions and technical attributes of this security unit. These measurements should be verified against your existing door cut-outs to ensure a perfect fit.
| Specification | Details |
|---|---|
| Case Size | 73mm (3 inch) |
| Backset | 44mm |
| Deadbolt Material | Brass with hardened steel rollers |
| Latch Bolt | Brass |
| Follower | Sintered Iron |
| Faceplate Dimensions | 200mm by 25mm |
| Centres | 56mm |
| Case Height | 148mm |
| Finish | Satin chrome plated forend |
| Security Level | 5 Detainer (High security) |
When selecting your final hardware, consider the overall thickness of your timber door. This lock is compatible with doors up to 50mm in thickness, providing a robust anchoring point for the striking plate. The box strike, finished to match the satin chrome forend, ensures that the visual transition between the door and the frame remains clean and professional. Whether you are refurbishing a historic building or fitting out a new commercial space, this lock offers a blend of performance and aesthetic appeal that few other products can match.
Our team at Doorfit is dedicated to helping you find the perfect solution for your security needs. If you have any remaining questions about the installation process, or if you need assistance determining the correct handing for your specific door, we are here to support your requirements. Trust in the legacy of this design and secure your property with hardware that provides genuine protection.
Specification
| Manufacturer | Union |
|---|---|
| Dimensions | 148 (H) x 73 (D) |
| Guarantee | 10 Year |
| Lock Type | Mortice Sashlock |
| Lock Operation | Lever |
| Lock Backset | 44mm |
| 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 | Chrome |