Choosing the right preload and accuracy class for a linear guideway balances rigidity, running smoothness and service life.

Preload classes

• Light preload – smooth motion, low friction, for transport axes and light loads.
• Medium preload – higher rigidity for machining centres and precision positioning.
• Heavy preload – for heavy cutting and strong vibration, at the cost of higher friction.

Accuracy classes

Normal (C), high (H) and precision (P) classes define the parallelism and height tolerance of the block running on the rail. Machine tools typically use H or P class.

Installation tips

Fix the reference rail first, align the second rail to it, and tighten the bolts in sequence to the specified torque.