Multibolt With NightBolt union lock M3301 AB

Product Description

Ultimate Multi-Point Security for Exterior Doors

Multibolt With NightBolt union lock M3301 AB is a premium high-security mortice lock engineered for exterior wooden doors where maximum protection is non-negotiable. As part of Union’s renowned StrongBOLT range, the M3301 combines multiple locking points with a convenient NightBolt function, all finished in a warm Antique Brass tone that suits traditional and period properties.

Multibolt With NightBolt union lock M3301 AB

Unlike standard single-bolt locks that secure the door at one point, the M3301 extends multiple bolts into the door frame, typically at the top, middle, and bottom of the lock case. This distributes the locking force across a much larger area, making the door significantly more resistant to forced entry, crowbar attacks, and spreading techniques. The NightBolt feature allows you to engage a deadbolt from the inside without a key, providing instant security when you are at home. Union has been manufacturing locks in the UK since 1840, and the M3301 is BS3621:2007 certified.

BS3621 Certified Multi-Point Security

The Union M3301 AB is tested and certified to BS3621:2007, the most rigorous standard for mortice locks in the UK. This certification guarantees the lock has been proven resistant to drilling attacks, picking and manipulation, sawing and cutting, force and crowbar attacks, and bump attacks. Most UK home insurance policies require BS3621 locks on exterior doors. The M3301 exceeds this requirement with its multi-bolt design, offering security that goes beyond the standard.

What is a NightBolt and How Does It Work? The NightBolt is a deadbolt that can be engaged from the inside of the door using a thumb turn or snib without needing a key. When you are at home, you can lock the door from the inside with a simple turn. You do not need to find your keys to secure the door at night. The NightBolt provides the same hardened steel security as the keyed deadbolt. In an emergency, you can exit quickly without fumbling for keys.

Multibolt With NightBolt union lock M3301 AB

What Does “Multibolt” Mean? The “Multibolt” designation refers to the lock’s ability to extend multiple bolts into the door frame when locked. A typical M3301 configuration includes one latch bolt that is spring-loaded and operates with the handle for everyday closing, one keyed deadbolt that extends from the lock case when the key is turned, and one or two additional bolts that extend from the top and bottom of the lock case. This multi-point engagement means the door is secured at several points along its edge, dramatically increasing resistance to forced entry.

Antique Brass Finish

The “AB” suffix denotes the Antique Brass finish, a hand-finished, chemically aged brass that is lacquered to preserve its warm, vintage appearance. This finish is ideal for Victorian and Edwardian properties, traditional cottages and farmhouses, heritage renovations and listed buildings, and any exterior door where polished chrome or satin nickel would look out of place. The antique brass finish is applied to the faceplate, strike plates, and any exposed hardware. To clean, simply wipe with a soft dry cloth. Do not use brass polish, as this will remove the lacquered antique effect.

Complete Kit Contents

The Union M3301 AB package typically includes one multibolt lock body with latch, deadbolt, and NightBolt, two or three keys depending on configuration, one faceplate in antique brass finish, one or more strike plates for multi-bolt engagement, fixing screws for faceplate and strike plates, dust sockets for strike plates, installation instructions, and a template for morticing. Note: Handles, escutcheons, and cylinders are sold separately unless otherwise specified.

Technical Specifications

Model: Union M3301 AB. Type: Multibolt Mortice Lock with NightBolt. Standard: BS3621:2007 certified. Mechanism: 5-Lever or 6-Pin Cylinder. Finish: Antique Brass. Bolts: Latch, Keyed Deadbolt, NightBolt, plus optional additional bolts. Backset Options: 45mm, 57mm, or 68mm. Case Size: Varies by backset. Forend Size: 152mm x 25mm approximately. Bolt Throw: 20mm+ per bolt. Door Thickness: 35mm to 55mm. Keys Supplied: 2 or 3. Key Differs: 1,000+. Handing: Reversible. Warranty: 10 years against manufacturing defects.

Applications

The Union M3301 AB is designed for front doors, back doors, side doors, French doors when paired with appropriate flush bolts, and period properties where the antique brass finish matches existing hardware. This lock is not recommended for interior doors, metal doors, or uPVC doors. It is designed for timber wooden doors only. uPVC and composite doors require different multi-point lock mechanisms that are integrated into the door itself.

Multibolt With NightBolt union lock M3301 AB

Installation Guide

Installing a multibolt lock requires precision and experience. For best results, we recommend hiring a qualified carpenter or locksmith.

Tools Required: Drill with various bits including spade bits for morticing, chisels, mallet or hammer, screwdriver, tape measure and pencil, mortice gauge, and optionally a router for cleaner mortices.

Step 1: Mark the Door – Position the lock at your desired height, typically 900-1000mm from the floor. Mark the center of the keyhole, spindle, and any additional bolt positions on both sides.

Step 2: Drill the Keyhole and Spindle Holes – Drill the keyhole typically 25mm through the door. Drill the spindle hole typically 8mm at 90 degrees to the keyhole.

Step 3: Mortice the Lock Case – Mark the outline of the lock case on the door edge. Drill out the bulk using a spade bit, then chisel to the exact depth and shape. The lock case should slide in with a snug fit.

Step 4: Mortice for Additional Bolts – If your M3301 configuration includes additional bolts that extend beyond the main lock case, mortice the door edge and frame to accommodate these. This is the most critical step.

Step 5: Install the Lock Body – Insert the lock into the mortice. The faceplate should sit flush with the door edge. Secure with the provided screws.

Step 6: Install the Strike Plates – Close the door and mark the position of all bolts on the door frame. Mortice the frame to accept each strike plate. Secure with screws.

Multibolt With NightBolt union lock M3301 AB

Step 7: Install Handles and Cylinder – Attach your chosen handles and escutcheons. Insert the cylinder through the lock body and secure according to the manufacturer’s instructions.

Step 8: Test the Operation – Test the latch, keyed deadbolt, and NightBolt with the door open and closed. Ensure all bolts engage the strike plates without binding. Adjust as necessary.

Maintenance and Care

Lubrication: Apply a dry graphite lubricant to the keyway and bolt mechanisms annually. Do not use oil or WD-40, which can attract dust and gum up the mechanism. Cleaning: Wipe the antique brass finish with a soft dry cloth. Do not use brass polish. Key Care: Keep spare keys in a safe place. Inspection: Check the lock annually for signs of wear, loose screws, or sticking bolts. NightBolt Check: Test the NightBolt regularly to ensure it engages and disengages smoothly.

For insurance-approved, multi-point security with the convenience of a NightBolt and the elegance of an antique brass finish, the Union M3301 AB is the professional choice for exterior wooden doors.