Lock Installation & Maintenance Flashcards

When installing a cylindrical lockset, what is the standard backset measurement used in most US residential applications?

Answer: 2-3/8 inches

The standard backset for most US residential cylindrical locksets is 2-3/8 inches, measured from the door edge to the center of the bore hole.

Which tool is used to cut the edge bore hole for a cylindrical lockset installation?

Answer: Spade bit

A spade bit is typically used to drill the edge bore (latch hole) in the door edge for cylindrical lockset installation.

What is the purpose of a 'strike box' installed behind a door strike plate?

Answer: To provide a cavity for the latch bolt to retract into the frame

A strike box provides a recessed cavity behind the strike plate that allows the latch bolt to fully retract, enabling smooth door operation.

When installing a mortise lock, which measurement is critical for ensuring proper operation of the lock body within the door?

Answer: Mortise pocket depth

The mortise pocket depth must exactly match the lock body dimensions to ensure the lock sits flush and operates correctly within the door.

What type of lubricant is recommended for maintaining pin tumbler lock cylinders?

Answer: Graphite powder or dry PTFE lubricant

Graphite powder or dry PTFE (Teflon) lubricant is recommended for pin tumbler cylinders because it does not attract dirt or gum up the mechanism.

A door latch bolt is not retracting fully when the knob is turned. What is the MOST likely cause?

Answer: Broken return spring inside the latch mechanism

A broken or weakened return spring inside the latch mechanism is the most common cause of incomplete latch retraction when the knob is turned.

When installing a surface-mounted rim lock, the screws securing the lock body should be tightened to the door:

Answer: From the interior side through the back plate

Rim lock bodies are secured from the interior side through the back plate, ensuring tamper resistance from the exterior.