Measuring a door lock set is essential for ensuring compatibility and proper function. While a complete lock set involves multiple dimensions, a critical measurement is the backset.
Understanding Backset
The backset is the distance from the edge of your door (where the latch extends) to the center of the bore hole (the large hole drilled through the door where the main lock cylinder and knobs/levers are installed). This measurement is crucial for the lock to align correctly with the door frame strike plate.
How to Measure Backset
To measure the backset:
- Open the door.
- Locate the edge of the door where the latch bolt is.
- Measure the distance from the door edge to the center of the large circular hole (the bore hole) on the door face.
This measurement is typically given in inches.
Common Backset Measurements
According to information on measuring backset for a lock:
- Set normally on residential doors, you will find your backset to be 2 and 3/8 inches (2 3/8").
- Normally on commercial doors, you will find your backset to be 2 and 3/4 inches (2 3/4").
These are standard sizes, though other backsets exist for specific applications or older doors.
| Application | Common Backset Measurement (Inches) |
|---|---|
| Residential | 2 3/8" |
| Commercial | 2 3/4" |
While backset is a key measurement, other factors like door thickness and bore hole diameter (cross bore and edge bore) are also important when selecting or replacing a full door lock set. However, the backset is often the first measurement needed to determine compatibility.
