Medium Series Slewing Rings

Medium & Large series slewing rings

QCB defines its Medium Series slewing rings as larger modular sets or “families” of slewing rings, or other slewing rings under 2000mm in diameter that do not fit into the Light Series category.

In the Large Series, “anything goes” in terms of diameter (Largest quoted 12.2m!), construction (solid or segmented?) and internal construction (standard or wire race? special combination ball/roller?) or materials (stainless steel, aluminium?) etc.

Medium series slewing rings find application worldwide, but they have differing performance characteristics:-

The larger flanged bearings offer weight savings compared to solid section bearings, but have less torsional rigidity. They are therefore suited to the applications in which the load eccentricity is limited but a larger bore diameter is required.

The 25 series offers greater load capacity compared to the lighter 20mm series, as well as a high gear strength, especially as QCB geared slewing rings are manufactured in 42CrMo4 steel.  

The double row ball and triple row roller designs offer exceptional load capacity in a small diameter and are suited to applications where heavy loads with high eccentricty are to be found.

Typical applications include:

  • Large industrial positioners and jigs
  • Large loading chutes for trucks or marine loaders
  • Truck or ship mounted jib cranes, tower cranes, concrete pumps
  • Heavy duty conveyors in the mining and aggregate industry
  • Amusement rides
  • Winches, hose and cable carriers
  • Cradle carriers

Many variations of the basic medium series slewing rings exist including:-

  • US/ Imperial versions with inch dimensions and US stub gearing
  • Undrilled, double drilled and OEM drilling patterns
  • Reduced internal clearances including light preload
    Precision inner and outer diameters
    Zinc plating, epoxy painted or nylon coatings 
    High temperature spacers and seals
    Various lubricants depending on application
    Application specific / OEM designs


If you have a special application e-mail us for professional advice.



All QCB® slewing rings are manufactured to the highest possible quality levels in ISO certified factories.

The QCB® Quality Standard defines all aspects of their dimensions, materials, manufacturing, packing and labelling.

Whilst the data on the site is updated regularly, we reserve the right to implement subtle changes to these standards in our quest for continual product improvement.

Not sure what you need? Contact us and we will advise a solution based on your needs and budget!
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