What Size Cam Lock Do I Need for My Locker?

Choosing the correct cam lock size is essential when replacing locker locks. Ordering the wrong barrel length or cam dimension results in poor door engagement, security issues and unnecessary return costs.

This guide explains how to measure cam lock size correctly, including barrel length, cam length and door thickness. If you are selecting replacement locker locks, accurate measurement is the first step.

Understanding Cam Lock Components

Before measuring, understand the parts of a cam lock:

• Barrel: The threaded cylindrical body passing through the door.
• Cam: The flat metal arm that rotates to secure the frame.
• Retaining nut: Secures the lock to the door.
• Keyway: The slot where the key enters.

Size errors usually relate to barrel length or cam length.

Measurement 1: Barrel Length

Barrel length is measured from the front face of the lock to the rear of the threaded section.

• Remove the retaining nut.
• Withdraw the lock from the door.
• Measure the threaded body only (not including cam).

Common UK barrel lengths include 15mm, 20mm and 25mm.

Measurement 2: Cam Length

Cam length is critical. It determines how far the cam arm reaches behind the locker frame.

• Measure from the centre of the cam fixing hole.
• Measure to the outer tip of the cam arm.

Incorrect cam length leads to:

• Door not securing fully
• Excessive movement
• Frame misalignment

Measurement 3: Door Thickness

Locker door thickness affects barrel selection.

• Metal lockers typically 0.7–1.0mm steel
• Laminate or plastic may differ

If the barrel is too short, the retaining nut cannot secure properly. If too long, excess thread may cause instability.

Standard Cam Lock Size Table

Application	Typical Barrel Length	Typical Cam Length
School Metal Lockers	20mm	15–20mm
Gym Steel Lockers	20–25mm	20mm
Laminate Doors	25mm+	20–25mm
Heavy-Duty Industrial	25mm+	25mm+

Common Mistakes When Measuring Cam Lock Size

• Measuring total lock length including cam
• Guessing based on appearance
• Ignoring door thickness
• Ordering without removing lock

Mastered vs Non-Mastered Cam Locks

If your locker system uses master keys, ensure the replacement matches the mastered configuration. Installing non-mastered locks breaks central access control.

Review available locker lock options before placing orders to confirm compatibility.

When to Upgrade Instead of Replace

If repeated measurement errors or failures occur, it may indicate inconsistent historical installation. Standardising lock size across the facility simplifies maintenance.

Final Thoughts

Selecting the correct cam lock size is a precision task. Accurate measurement prevents return costs, door misalignment and premature failure.

If you are ready to order correctly sized replacement locker locks, confirm barrel length, cam length and door thickness before purchasing.