HOW TO MEASURE A WINDOW LOCK

HOW TO MEASURE A WINDOW LOCK

STEP 1 : NOTE THE POSITION OF THE LOCKCASE RELATIVE TO THE FACEPLATE

In the first instance you should note the position the lockcase relative to the faceplate - inline or offset.

The top example shows an offset lockcase - it is positioned on one side of the faceplate.
An inline lockcase (as per the image on the bottom) sits centrally on the faceplate.

 
 
 
 
 
 
 

STEP 2 : IDENTIFY THE RAIL SHAPE

 
Looking at the rail end-on, identify the rail shape (see Fig. 1).

The top image is a flat rail; the bottom image shows a u rail.

 
 
 
 
 
 

STEP 3 : TAKE THE MEASUREMENTS

The next step is to take a series of measurements:
A: Backset The distance from the middle of the spindle to the front face of the lock.
B: Faceplate length The distance from the top to bottom of the faceplate which sits flush on the window.
C: Faceplate width Horizontal width of the faceplate that sits flush to the window.
D: Cam height The height of the mushroom (or roller) cams at each end of the rail.