How to measure a Cylinder Lock
Friday, 4 June 2021
Finding the Right Size Cylinder
Measuring from Existing Cylinder
Many cylinders are held in place by a Fixing Bolt that is screwed from the door edge through a threaded hole on the side of the cylinder under the cam. The cylinder size required is determined by the distance from each edge of the cylinder to the centre of the Fixing Hole.
Mark Long Cylinders - If the existing cylinder sticks out more than 5mm, use a pencil to mark on the cylinder the point that it leaves the backplate. This mark should then be used for measuring, rather than the end of the over sized cylinder.
Remove the Euro Cylinder - If you are unsure, instructions on next page.
Lay the Cylinder Down - Place cylinder on a flat and level surface on it’s side for measuring.
Check Measurements -
Measuring to the Fixing Hole is the most common method of measuring cylinders. However some people do not include the 10mm cam space in the centre of the cylinder.
Removal of Existing Cylinder
Open the Door - Insert key to unlock and open the door. Leave key in lock.
Remove Fixing Bolt - The cylinder is held in place by a long threaded bolt/screw.
Pull Cylinder Out - Turn the key while applying slight pressure to the opposite end of the cylinder.
Fitting a New Cylinder
Align Cam and Cylinder - Insert the key and turn until the cam is no longer sticking out and is lined up with cylinder.
Insert Cylinder - Holding the key and cylinder, guide through the cylinder cut-out on the door.
Fit Fixing Bolt - Insert Fixing Bolt through hole in the door edge and feel to locate the cylinder Fixing Hole. When it feels like the Fixing Bolt has found the Fixing Hole, screw the bolt until it and the cylinder is secure.