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56mm Flanged Light Series 20 (External Gear)

FEG 20 Series (Flanged External Gear)

A popular "light" series of slewing rings used in a variety of simple mechanical handling devices where rotation is effected by the addition of an external metric spur gear

Similar bearings are made by other manufacturers which can generally considered interchangeable. However there can be important differences and customers are urged to ask our Technical Department for advice.

This metric series is similar to the KAYDON RK6-E range which is manufactured to imperial dimensions and has an American involute stub gear. It is usually easy to change to the European bearing and use a stock metric pinion to achieve a similar speed ratio on the gear. 

Withing the QCB® range we can offer:-

  • The widest size range on offer
  • Double or non standard drilling patterns
  • High precision bearings with location diameters
  • Zinc plating, black oxide, paint or Nylon coatings for corrosion resistance
  • A variety of separators for high temp. or high speed applications.


Full 56FLS20 Series datasheet HERE 


FEG 505 20   FEG 650 20   FEG 750 20   FEG 850 20   FEG 950 20   FEG 1050 20   FEG 1200 20


Available on request


* - suffices dependent on final bearing specification e.g FEG 650 20 51 AA LM

Fzn = Gear force Normal; Fzm = Gear force Maximum


From 2014 all QCB®  geared slewing rings are made in 42CrMo4

Other manufacturers typically use C45 steel (European) or 50Mn (China), roughly equivalent to BS 080M46

Grease points

Usually supplied with 4 grease points in the inner ring only, DIN 71412A M8x1 equispaced

Bearings can be supplied with hardened gear or in different materials to order.

Load and bolt limit curves

If there are both radial and axial loads acting on the bearing, these need to be converted to a single equivalent load to enable accurate graphical analysis. Bearings should operate within the prescribed triangular area at all times.

The bolt limit curve is based on the use of Grade 8.8 bolts. An improvement to this can be achieved by using Grade 10.9 bolts, but only after approval of the NBC Technical Department.

If the load is suspended, or the axis of rotation is not vertical, refer application details to


Units: Y-Axis = Moment load in KN.m; X-Axis = Axial load in KN

Interchange information

This table offers generally accepted interchange numbers. However as variations exist all queries should be referred to our Technical Department for analysis.

Dimensional equivalance does not always imply equal performance.

* - suffices dependent on final bearing specification. This information subject to change without notice.

For professional assistance contact the NBC Slewing ring experts by phone on+44 (0)1952 222300, by fax on +44 (0)1952 242938 or e-mail

Whilst every effort has been made to ensure the accuracy of the information on this website, if you spot a mistake please inform the Thanks!