HydroRound II Rotary B-axis

The HydroRound II is a hydrostatic oil rotary bearing designed to sit on the Z-axis of drum roll lathes and Precitech’s Nanoform® machines for tool machining.

The system can be rotated meaning the diamond tool can access any orientation, across 360 degrees, throughout the machining process. In addition to this, for parts with a diameter greater than 200 mm, the tool holder can sit beyond the edge of the rotary axis.

The HydroRound II has improved encoder error mapping systems, which provides:

  • For tools located within 100 mm of the center, a form accuracy of XZB acceptance is valid
  • A ten times better improvement in position accuracy
  • The use of the B-Axis as a highly precise tool turret


  381 mm (Nanoform 700 Ultra) 330 mm (Nanoform X and Drum Roll Lathes)
Table Top Size 381 mm (15 in.) dia. 330 mm (13 in.) dia.
Load Capacity 454 kg (1000 lbs.) 225 kg (500 lbs.)
Max. Speed 10 RPM
Motor Torque 6.8 N-m (6 ft-lbs.) 4.1 N-m (3 ft-lbs.)
Radial Error Motion 0.10 μm (4 μin.) @ 1 in. above table*
Coning Error 1.0 nm/mm (1.0 μin./in.)
Radial Stiffness 525 N/μm (3,000,000 lbs./in.) 225 N/μm (1,280,000 lbs./in.)
Axial Stiffness 875 N/μm (5,000,000 lbs./in.) 600 N/μm (3,428,000 lbs./in.)
Moment Stiffness 17 N-m/μrad (150 lbs.-in./μrad) 3.4 N-m/μrad (30 lbs.-in./μrad)
Positioning Accuracy +/- 0.1 arc-sec (10x improvement in industry standard of +/- 1 arc-sec)

*Can be reduced to <1 μin. at the working height of the tools by employing Precitech's exclusive UltraMapping option

HydroRound II Rotary B-axis

Large HydroRound® II on a Freeform® TL with Levicron Spindle
Small HydroRound® II on DRL2000HS
Large HydroRound® II on a Freeform® TL used as an ultra precision tool turret Shown with 10 fixed tools, dual FTS1000, 2 marking spindles (or Levicron spindle), and 16 individual spray mists

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