Bored lever or knob set (ANSI/BHMA A156.2)
Two bores: a 2-1/8 in cross bore through the face for the knob, and an edge bore for the latch. Dimensions are so consistent that a retrofit can be designed blind — backset 2-3/8 in or 2-3/4 in covers almost everything.
Also called: Tubular lockset · Bored lock · Entry lever · Knob set
Installation Photos & Retrofit Diagrams
Field installation examples, drive schematics, and common retrofit failure modes for this lock family:
US-30
knob / lever lock — Standard tubular entrance knob/lever
R0
Engineering Specifications & Installation
Field Photo · Blueprint
🛠️ 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-30
🔬 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
AU-18
knob / lever lock — Whitco tubular entrance knob/lever
R0
Engineering Specifications & Installation
Field Photo · Blueprint
🛠️ 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-18
🔬 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
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: London · Sydney · Melbourne · Manchester · Brisbane
⚙️ 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: 84/100 · Urban condo tenants & apartment owners
🔑 Tenant Zero-Damage Grade: Grade A- (No-drill cylinder clamp & slim gate safe) · Est. Install: 8 mins
🛠️ Recommended Retrofit Kit: ADP-05 + ADP-07
☀️ Salt Spray & Weatherproofing: ASTM B117 / EN 1670 Grade 4 Corrosion Resistance · IP55
🌡️ Thermal & Gasket: +55°C · Flame-retardant anti-fungal EPDM silicone weatherseal gasket
🔄 Multipoint Kinematics & Torque: Lift Angle: 45° Upward handle stroke · Drive Torque: Drive resistance 0.35 - 0.60 N·m
🔧 Hardware Vendors & Tuning: Winkhaus autoLock, GU-Secury, KFV/Siegenia · Adjust eccentric strike plate cams using hex key to reduce latch binding
🚪 Door Thickness & Fasteners: Nominal Door: 35mm ~ 50mm ()
🔩 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
🔨 Field Installation Cases & Jobsite Photos (1 cases)
Authentic jobsite photos of jig drilling, mortising, tailpiece pulling, and strike alignment.
Anatomy
- Chassis inside the cross bore
- Latch assembly in the edge bore, with a 2-1/4 × 1-1/8 in faceplate on residential sets
- Tailpiece connecting the outside trim to the chassis
- Cylinder in the outside knob or lever, or a separate deadbolt above
Parameters to measure
Measure in this order: Backset (Dornmaß) → Cross bore diameter → Edge bore diameter → Door thickness
| Parameter | Typical values | Tolerance that still fits | How to measure |
|---|---|---|---|
| Backset (Dornmaß) | 2-3/8 in (60 mm) residential, 2-3/4 in (70 mm) exterior and commercial | Adjustable latches cover both | Door edge to the centre of the 2-1/8 in bore. |
| Cross bore diameter | 2-1/8 in (54 mm) | — | Measure across the round hole in the door face. |
| Edge bore diameter | 1 in (25 mm) or 2-1/8 in | — | Measure the hole in the door edge. |
| Door thickness | 1-3/8 to 1-3/4 in (35–45 mm) | Thicker doors need extension kits | Measure at the bore. |
Retrofit architectures that work
- Motor replacing the interior handle — The interior lever or knob is replaced by a motor unit that drives the 8 mm spindle directly. The outside keeps the original key cylinder and handle. This is the cleanest fit for mortise locks where the bolt is thrown by the key and the handle only retracts the latch.
- Full lock replacement on the same footprint — The old lock case is removed and a smart lock with the same footprint takes its place. This is the dominant approach in East and Southeast Asia, where push-pull digital locks replace mortise sets on HDB, condo and apartment doors.
- Surface motor on a deadbolt turn-piece — An adhesive or screw-fixed motor sits on the door face and rotates the existing deadbolt turn-piece. Nothing is drilled. This is the standard approach for North American single-cylinder deadbolts and for many Asian rim deadbolts.
Two very different retrofits live here. On a lockset with a key in the knob, you replace the whole set with a smart lockset on the same bores. Where there is a separate deadbolt above, the cheap and reliable answer is a motor on the deadbolt's turn-piece instead.
Related standards
ANSI/BHMA A156.2 · ANSI/BHMA A156.36
Questions
What does Grade 1 mean?
The highest ANSI/BHMA durability grade. For bored locksets Allegion lists 1,000,000 cycles at Grade 1; other published tables give 800,000. Cite the edition when you use the number.
Can I just swap the outside knob?
Usually no — chassis and tailpiece geometry differ between makers even when the bores match.