Centre Distance of Shafts
This is the measurement in millimetres, between the centre line of the two shafts. It is the main designation of an MMD sizer and is often referred to by the series number i.e. 500series sizer = 500mm centre distance(centres).

This distance combined with the tooth design and configuration controls the maximum size of infeed material that the unit can process efficiently.

Length of Inlet
The length of inlet is the length in millimetres of the sizing chamber.

The length of the inlet is a major factor in the volume of material that the unit can process.

Tooth Configuration
The tooth configuration in conjunction with a breaker bar, when fitted, controls the product size

Inward/Outward Shaft Rotation

Inward shaft rotation is the standard method of operation for most types of tooth configuration and must be used on wet/sticky materials.
Outward running is usually only employed on secondary machines for certain materials to produce a smaller product than is possible running inwards.