 Need to understand how euro cylinders are measured?  We go into the detail on the 3 types of cylinder; Single, Double and Cylinder and Turn, and our download makes it even easier, simply place your cylinder on the guide and read off the dimensions.

Firstly, identify which type of cylinder you require, single, double or cylinder and turn.  If you are replacing a cylinder, then we recommend that you remove it from the door, to make it easier to measure.

1. Single Cylinder (Half Cylinder)

A single cylinder has a key on onside only,  All cylinders are measured from the centre of the screw hole below the cam, this is highlighted in the drawing below via a red dotted line.  When measuring your cylinder, take the measurement from the same place. 1. Lay the cylinder down on a flat surface.
2. From the centre of the screw hole (marked by the red dotted line) firstly measure the left hand side
3. The right hand side always measures 10mm.
4. Double check this measurement, by measuring the complete length of the cylinder, the sum of steps B & C should be the same as the total length.

For example a 35mm left and 10mm right would be a 35/10 single cylinder.

2. Double Cylinder (Key Both Sides)

A double cylinder has a key on both sides,  All cylinders are measured from the centre of the screw hole below the cam, this is highlighted in the drawing below via a red dotted line.  When measuring your cylinder, take the measurement from the same place. 1. Lay the cylinder down on a flat surface.
2. From the centre of the screw hole (marked by the red dotted line) firstly measure the left hand side
3. Then measure the right hand side.
4. Double check this measurement, by measuring the complete length of the cylinder, the sum of steps B & C should be the same as the total length.

When these measurements are identical they are refered to as an equal cylinder, for example a 30mm left and 30mm right would be a 30/30 double cylinder.

When these measurements don't match they are refered to as an unequal cylinder, for example a 60mm left and 40mm right would be a 60/40 double cylinder.  These un-equal cylinder types are common on PVC doors.

3. Cylinder & Turn (Key ONe Side)

A cylinder and turn has a key on one side and a thumb turn on the other (this allows the lock to be used with out a key on the turnside),  All cylinders are measured from the centre of the screw hole below the cam, this is highlighted in the drawing below via a red dotted line.  When measuring your cylinder, take the measurement from the same place. 1. Lay the cylinder down on a flat surface with the tumb turn on the right hand side.
2. From the centre of the screw hole (marked by the red dotted line) firstly measure the left hand side
3. Then measure the right hand side.
4. Double check this measurement, by measuring the complete length of the cylinder, the sum of steps B & C should be the same as the total length.

When these measurements are identical they are refered to as an equal cylinder, for example a 30mm left and 30mm right would be a 30/30T cylinder and turn.

When these measurements don't match they are refered to as an unequal cylinder, for example a 60mm left and 40mm right would be a 60/40T cylinder and turn (the "T" denotes which side the thumbturn is located).  These un-equal cylinder types are common on PVC doors. 