Key Takeaways:
High-end hydrostatic systems reach oil-film stiffness above 500 N/μm—5–10× that of rolling bearings. Stiffness this high resists cutting force and load deflection, protecting accuracy.
Stiffness in Plain Terms
Stiffness is how much force is needed to deflect the support by a given amount. A hydrostatic oil film can reach stiffness above 500 N/μm, meaning it takes more than 500 newtons to push the film down by a single micron.

5–10× Rolling Bearings
This is 5–10× the stiffness of a comparable rolling bearing. The highest stiffness comes from membrane-feedback restrictors, which continuously compensate cavity pressure as load changes. Higher stiffness means cutting forces and workpiece weight deflect the support far less.
Why It Protects Accuracy
Less deflection under load translates directly into better geometric accuracy and surface finish—especially in heavy grinding or large rotary-table work where load varies through the cycle.