Typically the main components (with different usages) in the machine tools are:

• the mandrel;
• the feeding unit.

The mandrel:

The bearing in these applications must give the mandrel:

• high stiffness (used as a parameter in the choice of the bearing instead of the load coefficient);
• extremely high quality in concentric rotation and axial displacement (motion accuracy);
• adjustable clearance during the assembly;
• low friction;
• excellent balancing quality.

All these properties do guarantee:

• a highly reduced shape defects;
• a better superficial finishing of the item;
• a longer tool life;
• a higher removal efficiency.

The feeding unit:

The precision of the feed of the machine tool together with the component depends on the type of the machine and the devices used to control it are ribs guides, grooved bars, screw die systems, viti a ricircolo di sfere per il recupero dei giochi. And the essential required properties are:

• high stiffness;
• high shape precision;
• perfectly calibrated clearances/pre-loads;
• low friction.

All the above mentioned properties are peculiar to the housings used in linear systems like:

• rolling guides;
• ball couplings;
• screw-down bearing

Medium to high dimension, extremely stiff, zero-backlash bearings are used either in the mandrels or the feeding units in any positioning operations.