Begin by confirming the door’s construction type (steel, wood, or metal‑clad) and the door’s thickness. Grade 1 deadbolts require a minimum 1‑½‑inch backset; if the existing backset is 1‑¼‑inch, a backset extender must be installed. Use a calibrated digital caliper to measure the distance from the edge of the door to the center of the bore hole. Verify that the door’s fire‑rating allows modifications—most commercial doors are rated to 90 minutes and can accommodate a 1‑inch mortise without compromising integrity, provided the fire‑stop seal is re‑applied after installation.
Mark the lock’s strike plate location on the frame. The strike must be centered vertically on the jamb, with a tolerance of ±0.125 in. Drill a pilot hole using a 5 mm carbide bit at the marked point, then enlarge it with a 13 mm spade bit for the latch bolt. For steel frames, insert a ½‑inch hardened steel reinforcement plate behind the strike before securing it with four #10 × ½‑in. self‑tapping screws. Tighten each screw to 20 Nm using a torque wrench; over‑torquing can strip the threads and reduce the strike’s holding power.
Next, create the lock bore on the door. Position the deadbolt’s template, aligning the keyway face with the edge of the door. Drill a 13 mm pilot hole for the latch bolt, then a 22 mm hole for the deadbolt body using a hole‑saw. Remove the core, then mortise the lock face using a 1‑inch square chisel to a depth of 0.75 in. Ensure the mortise is flush with the door surface—any protrusion will prevent the lock from seating properly. Insert the deadbolt, engage the latch, and secure the lock body with three #12 × ½‑in. security screws, torqued to 25 Nm. Verify that the deadbolt extends fully when the key is turned; the bolt should protrude 1‑inch beyond the frame.
Finally, conduct a functional test. Engage the deadbolt from both the interior and exterior, confirming smooth operation and proper strike alignment. If the bolt does not fully engage, adjust the strike plate by loosening the screws, shifting the plate up or down in 0.025‑in increments, and retightening. Apply a tamper‑resistant sealant around the lock’s exterior face to meet UL 294’s environmental protection criteria. Document the serial numbers, torque settings, and any adjustments made on the installation log sheet provided in the course materials.
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