Fixed the Cylinder Now the Strike Misaligns: Second-Fault Masking Decision Tree

Why this matters

When a sticky cylinder is the loudest fault, customers stop using the deadbolt or use it gently. That hides a second fault: a strike that has drifted, a door that has sagged, or a frame that has settled. Once you fix the cylinder and the customer turns the key with normal force, the masked alignment fault surfaces and they call you back. The right move is to look for the second fault before you leave the first visit. This tree forces that check into your standard close-out sequence.

Step 1: Recognize the pattern

You finished a cylinder service, a rekey, or a lockset replacement. The cylinder turns smoothly off the door. The latch or deadbolt now refuses to throw fully, throws but binds on return, or throws but the door has to be lifted or pushed to engage. The fault was there before; the old sticky cylinder hid it because nobody could turn the key hard enough to feel it.

If the customer says "it never did this before," they are correct from their experience and wrong about the mechanism. Both faults pre-existed; only one was visible.

Step 2: Open-door functional test

With the door open, throw the deadbolt and the latch repeatedly. Watch the bolt extend and retract:

• Bolt extends fully and retracts smoothly with the door open: the lockset is fine. The fault is at the strike or door swing.
• Bolt extends fully but retracts with hesitation: the cylinder cam or the lockset chassis is dragging. Re-bench the lockset.
• Bolt does not extend fully even with the door open: the lockset itself has a fault. Go back to the cylinder, cam, and chassis.

Document which case you have before touching the strike.

Step 3: Measure the misalignment

With the door closed at rest, look at the gap between bolt and strike opening. Hold a flashlight inside the jamb. Identify the offset direction:

• Bolt sits high relative to strike pocket: hinges have worn or screws have backed out, door has dropped.
• Bolt sits low: top hinge is loose or jamb has lifted.
• Bolt sits proud of the strike face: door has shifted toward the hinge side, gap at the latch edge is too wide.
• Bolt rubs the bottom of the strike opening on throw: door has sagged or the strike has migrated up.

A business card test quantifies the gap: a single card slips, two cards bind, three cards will not enter. Anything tighter than one card on the bolt face means real interference.

Step 4: Decide between strike adjustment and door correction

Use this gate, not customer pressure:

• Misalignment under 1/16 inch in any direction: file the strike opening, no door work needed.
• Misalignment 1/16 to 1/8 inch: enlarge the strike pocket or move the strike one screw-hole position; may also require lengthening the mortise behind the strike.
• Misalignment over 1/8 inch: door or frame correction. Tighten loose hinge screws (replace with 3-inch screws into the framing if the short screws have stripped), shim a hinge, or plane the latch edge. Moving the strike that far weakens the jamb wood and produces a visible mismatch with the existing mortise.
• Bolt does not reach the strike at all: door has swelled or hinges are bound. Address the door first, never deepen the strike pocket to compensate.

Step 5: Verify the deadlatch is not the culprit

On a key-in-knob or lever set, the small auxiliary deadlatch pin must contact the strike face when the door is closed. If the strike pocket is too deep, the deadlatch pin drops into the pocket and the main latch becomes credit-card-vulnerable, plus it can hang up on retraction. Check that the deadlatch pin rides on the strike plate flange, not in the pocket. Reposition the strike or shim it forward if the pin is dropping.

Step 6: Hinge and screw audit

Before you sign off, open the door fully and check every hinge screw. Long-term sag almost always traces to one stripped or short screw in the top hinge pulling the door down. Replace at least one screw per hinge leaf with a 3-inch wood screw that reaches the rough framing. This correction often resolves a strike misalignment without any strike work at all.

Step 7: Close-out test sequence

Before you collect payment, run this sequence with the customer watching:

• Throw the deadbolt with the door open. Smooth full throw.
• Throw the deadbolt with the door closed. Same smooth throw, no lift, no push.
• Retract the deadbolt. Same smoothness.
• Repeat on the latch.
• Operate the key from the outside.

If any step requires more than a light wrist turn, you have not finished. Re-enter the tree at step 3.

References

• ANSI/BHMA A156.2, Bored and Preassembled Locks and Latches
• ANSI/BHMA A156.115, Hardware Preparation for Wood Doors
• NFPA 80, Standard for Fire Doors and Other Opening Protectives (for rated assemblies)
• Door and Hardware Institute, Installation Guide for Doors and Hardware