FUN 20 Imperial Series

A pair of flange profile rings separated by a 3/4" ball set; a constant section height of 2.205" and a standard range of external diameters ranging from 20.39" to 47.17" to match American dimension and bolt standards

All QCB® slewing rings are manufactured to the highest possible quality levels in ISO certified factories. A QCB® Quality Standard defines all aspects of their dimensions and tolerances as well as all aspects of manufacturing from materials properties, all stages of production, as well as 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.


While a flange reduces the overall weight of the bearing, it also reduces its torsional rigidity and these bearings are thus best suited to light or medium duty applications where there is not a high load eccentricity.

  • Industrial positioners (e.g. welding assemblies and jigs)
  • Ship or truck loading chutes and swivels
  • Stretch wrapping machines
  • Conveyors and other materials handling equipment
  • Simple amusement rides

If the IMPERIAL sizes and bolt patterns are not quite right, consider the FUN20 Metric Series

Need help?

Our technical team have many years of experience and are happy to assist with selection. Call or e-mail them for fast, efficient and professional advice.

The Design Form will assist you in defining your application details.

QCB referenceOutline dimensions & weight
FUN 518 20 61 CC LM20.39011.97017.87016.22016.14014.49058
FUN 648 20 61 CC LM25.51017.09022.99021.34021.26019.61076
FUN 748 20 61 CC LM29.45021.03026.93025.28025.20023.55089
FUN 848 20 61 CC LM33.39024.97030.87029.22029.14027.490104
FUN 948 20 61 CC LM37.32028.90034.80033.15033.07031.420118
FUN 1048 20 61 CC LM41.26032.84038.74037.09037.01035.360132
FUN 1198 20 61 CC LM47.17038.75044.65043.00042.92041.270153
QCB referenceOuter holesInner holes



FUN 518 20 61 CC LM19.250813.130121
FUN 648 20 61 CC LM24.3801218.13015 2
FUN 748 20 61 CC LM28.3801222.13018 3
FUN 848 20 61 CC LM32.2501526.13018 4
FUN 948 20 61 CC LM36.2501830.00018 5
FUN 1048 20 61 CC LM40.1301834.00020 6
FUN 1198 20 61 CC LM46.0001839.88024 7
Standard grease fitting# at least 2x 1/4"-28 UNF 2B on inner and outer rings

Interchange information

The FUN20 Imperial Series is interchangeable with bearings from other manufacturers such as Rotek, Kaydon, AVON, Silverthin . However there may be variations to this rule (e.g. OEM variants) and we invite you to refer to our technical staff for assistance.

Basic QCB refKaydonAvonRotekSilverthin
FUN 518 20 61 CC LMRK6 16 P1Z716 MC1L6 16 P9ZSK6 16 PZ
FUN 648 20 61 CC LMRK6 22 P1Z721 MC1L6 22 P9ZSK6 22 PZ
FUN 748 20 61 CC LMRK6 25 P1Z725 MC1L6 25 P9ZSK6 25 PZ
FUN 848 20 61 CC LMRK6 29 P1Z729 MC1L6 29 P9ZSK6 29 PZ
FUN 948 20 61 CC LMRK6 33 P1Z733 MC1L6 33 P9ZSK6 33 PZ
FUN 1048 20 61 CC LMRK6 37 P1Z737 MC1L6 37 P9ZSK6 37 PZ
FUN 1198 20 61 CC LMRK6 43 P1Z743 MC1L6 43 P9ZSK6 43 PZ

Custom designs

  • Double drilled or custom drilling patterns
  • Higher precision bearings with location diameters
  • Reduced internal clearance (Class 5 & Class 6)
  • Black oxide (standad) or zinc plating (to order) for enhanced corrosion protection
  • Epoxy paint or even Nylon coated units to special order
  • Stainless steel or aluminium versions


FUN20 Imperial Series slewing rings are normally produced in 50Mn / C45.

Internal construction

Standard FUN20 Series bearings incorporate plastic spacers, but ball spacers, steel or brass spacers, or even full complement and caged designs can be supplied for specific applications.


A land riding NBR (nitrile rubber) seal strip is standard. VITON seals can be supplied to order.


The FUN20 Imperial series is ungeared


QCB® Slewing rings are assembled with a small quantity of Lithium EP2 grease. It is important that all slewing rings are greased during installation and prior to operation.FUN20 Imperial Series slewing rings will usually have 4 or 6 grease nipples DIN 71412 M8x1 on the radial face of each ring. Sufficient grease nipples for all holes as well as Nylon plugs (to insert if a grease nipple is not required) are supplied with each ring.

Special greases can be supplied on demand as can GreaseMax Automatic Lubricators and Accessories.

Load & Bolt limit curves

If both a radial and an axial load act on the bearing these must be combines into a single equivalent load to enable basic selection from the load curves. The raceway limit is illustrated by the blue line, the red line illustrates the limit for the specified number of Grade 10.9 bolts. The load point should be well under the relevant load curve for long life.

Grade 8.8 bolts can be used but only after approval by our technical team.

Similarly if the load is suspended or the axis of rotation is not vertical please refer the application details to us and take advantage of our decades of experience!

# #
QCB referencePDF print
FUN 518 20 61 CC LMFUN 518 20 61.pdf
FUN 648 20 61 CC LMFUN 648 20 61.pdf
FUN 748 20 61 CC LMFUN 748 20 61.pdf
FUN 848 20 61 CC LMFUN 848 20 61.pdf
FUN 948 20 61 CC LMFUN 948 20 61.pdf
FUN 1048 20 61 CC LMFUN 1048 20 61.pdf
FUN 1198 20 61 CC LMFUN 1198 20 61.pdf

The 3D models for these bearings are available from 3DContentCentral - search for "QCB FUN"


Associated Products


Ensure an adequate supply of the correct grease to prolong slewring ring life


GreaseMax Auto Lubricators


Economical semi-precision turntables of similar diameter.

Trailer rings

Do you have a special project?

Need some advice? We can help!

01952 222300