Medeco 310100J Bi-Level 31 Series Large Format Interchangeable Core for Yale DL Keyway

Medeco 310100J Bi-Level 31 Series Large Format Interchangeable Core for Yale DL Keyway

The Medeco 31 Series Large Format Interchangeable Core (LFIC) is a heavy-duty, Grade 1 commercial cylinder engineered to retrofit Yale LFIC mortise housings, rim, key-in-knob, and padlock bodies. Featuring the Bi-Level (Medeco 4 / M4) cylinder technology with a DL keyway, this core allows non-technical personnel to quickly rekey locks using a special control key — no disassembly required. Constructed of durable machined brass components, the 31 Series positions its control/locking lug at the back of the cylinder, eliminating the need for build-up or control pins and simplifying integration into existing master key systems.

Key Features

• Tool-Free Core Changeability: Cores can be quickly and easily changed by non-technical personnel using a special control key, effectively "rekeying" the lock without disassembly — reducing the cost of routine rekeying service calls.
• UL437 Listed: Provides assurance that cylinders meet universal standards for drill and pick resistance and stand up to other types of forced attack.
• 31 Series Control/Locking Lug Design: The control/locking lug is positioned at the back of the cylinder, activated by an extra-long key. This eliminates the need for build-up or control pins, simplifying pinning and enabling integration into existing master key systems not originally designed for interchangeable core pinning.
• Yale LFIC Retrofit Compatibility: The 31 Series is specifically designed to retrofit Yale LFIC mortise housings, rim, key-in-knob, and padlock bodies for seamless upgrades to existing hardware.
• Patented Medeco 4 (M4) Bi-Level Technology: Keys may only be duplicated by Medeco or an authorized Medeco service outlet and only at the owner's request, providing utility patented key control.
• Durable Machined Brass Construction: All cylinder components are constructed of machined brass, designed to last the life of the equipment in demanding commercial environments.
• Flexible Keying Options: Cylinders can be ordered keyed alike, keyed different, or master keyed to accommodate a wide range of security system configurations.
• Multiple Finish Options: Available in 13 finishes including Bright Brass, Satin Brass, Antique Brass, Bright Bronze, Satin Bronze, Oil Rubbed Bronze, Bright Nickel, Satin Nickel, Antique Nickel, Black, Dark Bronze, Bright Chrome, and Satin Chrome.

Certifications & Compliance

• UL437 Listed — Drill and Pick Resistance Certified
• BHMA Grade 1
• Heavy Duty Commercial Rating

Technical Specifications

• Series: 31 Series Large Format Interchangeable Core (LFIC)
• Cylinder Technology: M3 BiLevel
• Pinning: 6-Pin
• Keyway: DL Keyway
• Certification: ANSI/BHMA A156.5 Grade 1 rated hardware platform
• Construction: Solid brass construction with nickel-plated pins and hardened stainless-steel drill-resistant pins
• Compatibility: Retrofits into existing LFIC-prepped hardware without replacement
• Warranty: 2-year manufacturer's warranty

Typical Applications

• Commercial Office Buildings
• Educational Facilities
• Healthcare Institutions
• Government and Municipal Buildings
• Retail Establishments
• Industrial and Warehouse Facilities
• Multi-Tenant Residential and Mixed-Use Properties

Why Medeco?

Medeco 31 Series LFIC cylinders are built from durable machined brass components and carry a UL437 listing for verified drill and pick resistance, delivering professional-grade security for demanding commercial applications. The patented Medeco 4 Bi-Level key control system ensures that key duplication is strictly controlled, while the back-of-cylinder lug design simplifies pinning and master key system integration — making the 31 Series a trusted choice for facilities requiring both high security and operational flexibility.