Measuring Euro Cylinder A/B Dimensions from the Central M5 Screw Hole Axis
Engineering Overview: Step-by-step measurement guide for determining internal (A) and external (B) Euro profile cylinder lengths relative to the central M5 screw axis.
Technical & Engineering Specifications
| Sizing Format | Dim A (Internal mm) / Dim B (External mm) |
|---|---|
| Standard Step | 5 mm Modular Increments (e.g. 30/30, 35/45) |
| Max Protrusion | <= 2.0 mm beyond exterior handle plate |
| Measurement Datum | Centerline of M5 retaining screw |
Standard Measurement Datum
Euro cylinder sizing is always expressed as two modular numbers: Dimension A (Internal) / Dimension B (External) in millimeters.
Step-by-Step Measurement
- Find Datum Axis: Locate the center of the M5 cylinder retaining screw hole on the door edge.
- Measure Dimension A: Measure from the M5 center to the inside door face (including handle backplate).
- Measure Dimension B: Measure from the M5 center to the outside door face.
- Example: A measurement of 35 mm inside and 45 mm outside gives a 35/45 mm (80 mm total) cylinder.
Frequently Asked Engineering & Selection Questions
Q1: How are Euro cylinder sizes written?
As internal length / external length in millimeters from the center screw (e.g. 30/40 mm means 30 mm inside and 40 mm outside).