Mortise lockset (ANSI/BHMA A156.13)

Q: How many cycles does a mortise lock survive?

Allegion lists 1,000,000 for A156.13 Grade 1 and 800,000 for Grades 2 and 3 — an unusual case where the lower grades share a number.

The commercial workhorse: a large case in a pocket in the door edge, with a huge function catalogue (passage, entry, classroom, storeroom, exit). Retrofit means understanding the function, not just the dimensions.

✓ verified · Where you will meet this lock: United States, Canada, commercial buildings worldwide

Also called: Mortise lock · Commercial mortise

⚡ 30-Second Retrofit Fit Check

3-Step Pre-Flight Verification to Prevent 90% of Stalls

1. Does door thickness and bore match standard mechanical specs?

2. Can original physical key operate smoothly from outside?

3. Is there sufficient indoor clearance for retrofit enclosure?

✓ Compliant with Global Retrofit Smart Lock Engineering Standards

⚙️ Operating Torque: 0.20 – 0.50 N·m (Nominal)

See installation diagrams and adapter specs below

Installation Photos & Retrofit Diagrams

Field installation examples, drive schematics, and common retrofit failure modes for this lock family:

📍 Jump to Category:

⌖ Mortise Lock Cases 5 ⌖ Specialty & High-Security 1

⌖ Mortise Lock Cases 5 models

Engineering Specifications & Installation Field Photo · Blueprint

📷 Real Field Door Installation Case

Heavy Commercial Mortise — Schlage L9000 Grade 1 Real Field Installation

Engineering field note: US-31 mechanism verification & retrofit compliance.

📐 1:1 Blueprint & Drilling Template

Heavy Commercial Mortise — Schlage L9000 Grade 1 Schematic & Template Blueprint

Includes backset, mortise pocket depth & spindle concentricity

🛠️ Tier 3: Standard Retrofit Installation Workflow

Step 1: Baseline Hardware Check — Verify backset, door thickness, and strike depth
Step 2: Baseplate Alignment — Secure mounting bracket, control concentricity (≤0.5mm)
Step 3: Drive Linkage Engagement — Fit custom adapter bushing or tailpiece coupler
Step 4: Door Close & Latch Cycle Test — Verify gap clearance and weatherstrip compression

📐 Recommended Clearance: ≥ 3.0mm (Door to Frame Gap) ⚡ Required Stall Torque: ≥ 1.2 N·m (Motor torque) 📄 Drilling Template ID: TPL-NA-US-31

🔬 Engineering Tolerance & Compliance Matrix Grade A (100% No-Drill / Interior Thumbturn Clamp)

Vertical Sagging Tol.:

±2.5mm

Weatherstrip Swelling:

≤1.8mm

Rated Stall Torque:

≥1.4 N·m (Anti-binding rating)

🚨 Emergency Egress Compliance: ANSI/BHMA Grade 1 Single-motion egress option (Back-drive drag: ≤0.35 N·m)

Complies with one-motion emergency escape requirements (anti-panic standard)

🏠 No-Drill / Rental-Friendly: 100% No-Drill Non-Destructive

100% reversible, safe for rental lease agreements

🔑 Keyway Specification: Standard regional keyway profile

❄️ Extreme Climate & Battery: -20°C low-temperature lithium cell recommended; alkaline cells derate by 40%

🔄 Handle Spring Resistance: Nominal handle return spring resistance 0.35 - 0.60 N·m

🔨 Chisel Mortise Rework & Reinforcement: Verify mortise pocket dimensions; apply wood reinforcement plate if clearance is tight

🔩 Through-Bolt & Wire Clearance: Through-bolt shear tolerance ±1.5mm; ensure wire harness conduit is fully protected

⚡ Motor Current & Battery Internal Resistance: Stall current 1.8A max; internal battery resistance threshold <120mΩ

🛡️ Security & Insurance Rating: Certified attack-resistant security standard

🧲 Door Sensor Gap & Metal Shielding: Magnetic gap threshold ≤15mm; anti-ferromagnetic shielding bracket required on steel doors

🏙️ Metropolitan Distribution: NYC · LA · Chicago · Toronto · Vancouver

⚙️ Gearbox Ratio & Back-Drive Torque: Recommended gear reduction ratio 120:1 to 180:1; planetary metal gearbox

📏 Shear Line Clearance & Depth: Clearance ≤1.0mm; thumbturn adapter recessed 5mm, dual pinch travel 2.5mm

🎯 Nuki Retrofit & ICP Profile: ★ Fit Score: 92/100 · Urban condo tenants & apartment owners

🔑 Tenant Zero-Damage Grade: Grade A- (No-drill cylinder clamp & slim gate safe) · Est. Install: 5 mins

🛠️ Recommended Retrofit Kit: ADP-04 + ADP-07

☀️ Salt Spray & Weatherproofing: ASTM B117 / EN 1670 Grade 4 Corrosion Resistance · IP54

🌡️ Thermal & Gasket: -40°C ~ +60°C · Flame-retardant anti-fungal EPDM silicone weatherseal gasket

🚪 Door Thickness & Fasteners: Nominal Door: 35mm ~ 45mm (1-3/8" ~ 1-3/4" )

🔩 Spindle & Bolt Spec: Spindle: 8mm square spindle bar · Bolts: M5 through-bolts cut-to-length based on door thickness

🛡️ Reinforcement: Architectural stainless steel reinforcement escutcheon plate

⚙️ Retrofit Engineering & Resistance Notes

Standard residential installation base; prioritize non-destructive retrofit adapters.

Minimum physical verification：Open / close mechanical test 3 cycles

Engineering Specifications & Installation Field Photo · Blueprint

📷 Real Field Door Installation Case

mortise lock — Lockwood Selector 3770/3772 Real Field Installation

Engineering field note: AU-14 mechanism verification & retrofit compliance.

📐 1:1 Blueprint & Drilling Template

mortise lock — Lockwood Selector 3770/3772 Schematic & Template Blueprint

Includes backset, mortise pocket depth & spindle concentricity

🛠️ Tier 3: Standard Retrofit Installation Workflow

Step 1: Baseline Hardware Check — Verify backset, door thickness, and strike depth
Step 2: Baseplate Alignment — Secure mounting bracket, control concentricity (≤0.5mm)
Step 3: Drive Linkage Engagement — Fit custom adapter bushing or tailpiece coupler
Step 4: Door Close & Latch Cycle Test — Verify gap clearance and weatherstrip compression

📐 Recommended Clearance: ≥ 3.0mm (Door to Frame Gap) ⚡ Required Stall Torque: ≥ 1.2 N·m (Motor torque) 📄 Drilling Template ID: TPL-UK-ANZ-AU-14

🔬 Engineering Tolerance & Compliance Matrix Grade B- (Semi-retrofit / Minor Screw Replacement)

Vertical Sagging Tol.:

±3.0mm

Weatherstrip Swelling:

≤2.5mm

Rated Stall Torque:

≥2.0 N·m (High-friction ABNT steel mortise)

🚨 Emergency Egress Compliance: ABNT NBR 14913 Emergency Safe (Back-drive drag: ≤0.35 N·m)

Complies with one-motion emergency escape requirements (anti-panic standard)

🏠 No-Drill / Rental-Friendly: Minor Screw Fit