Maintenance Service
for Machining Spindles

UKF Spindle Design: Experience since decades

UKF as a manufacturer of Spindle Bearings and Spindle Units is also busy in Retrofitting Spindles of various constructions.

After analysis of damages including about its causes follows approx. costs for repair.

If requested we propose technical improvements for better working performance, i.e like other types of bearings, other lubrication, other tool-fixing etc.

Each spindle re-assembled will be checked by measuring and running test.

What we supply:

  • working-, work-piece-, special purpose spindles with integrated motor or belt driven
  • manual or automatic tool-clamping
  • lubrication by grease, oil, oil-air
  • bearings with balls of steel or ceramic
  • various tool-faces
  • various sealing systems
  • various sensor equipments

So we grant a competent Spindle Retrofitting. Modernising Spindles means enabling to extended applications.

Specialties of the House

Double Row Spindle Bearing

Dimensions for the UKF Double Row Spindle Bearings correspond to a standard pair of Single Row Bearings in O-configuration ("DB"). Double Row Bearings, relative to single bearings, have better axial running accurancy due to the unitized outer ring and provide higher speed limits; the one-part outer ring imparts a higher stiffness to the bearing seat, and as a Floating Bearing, yields better axial guidance. Another advantage is the central lubricant feed, and the resulting extended lubricant reserve between the bearings. Assambly is simplified with reduced parts handling, and the bearings have the proper preload set at the factory. The inner rings need only to be locked against each other.

Optimum 21° Contact Angle

On modern Machine Tools, especially Machining Centres, expanded speed ranges are often required to meet productivity expectations. So on the one hand high rigidity for the working forces is required, on the other hand high speeds for efficient High Speed Cutting is needed.
With an intermediate contact angle of 21º, these bearings achieve excellent performance advantages over the more common 15º and 25º contact angle:

  • compared to 15°, a higher axial rigidityand axial load capacity
  • compared to 25°, a higher speed limit, i.e., higher RPM

Technical Book Roloff / Matek Machine Elements

Angular Contact Ball Bearings with Spacer Balls

like Bearings of Type series 70, 72 and 73 (double row). Long lifetime through high precision bearings. This configuration provides a slight self-aligning preload; consequently, the balls remain ander equal preload. These Bearings carry both radial and axial loads and provide spherical contact of the balls (DF).

  • Contact angle 16º, form factor to DIN 628 Part 5
  • Precision P5...P4...P2...HQ
  • double row with rolling ball guidance (Spacer Balls)

Bearing Cartridges

Cartridges are factory assembled sets of Spindle Bearings, preloaded and greased, complete with applicable seals, ready for installation. This reduces parts count, as well as manufacturing and assembly times, by combining Covers, Seals and Distance Rings into an easily installed, integrated assembly. Simply install the unit into a cylindrical bore in the applicable housing and insert the shaft. The bearings arrangement is possible various layouts: As DB up to QBC with distance ring to enlarge the supporting width.


Bearing Cartridges can be designed with Air Purge, Temperature-Monitoring, Vibration monitoring, variable preload VARIORING, cooling or heating capability, in order to maintain thermal equilibrium, such as in an air conditioned room.