21 Series slewing ring bearings
"L"-design four-point contact ball bearing, built to save weight. An "L" cross section reduces weight and installation space. Externally geared models combine a rectangular outer ring with a flanged inner ring; internally geared models do the reverse.
- Four-point contact, single-row ball design
- Plain, internally geared and externally geared versions
- Raceway diameters 13–57 in; other sizes on request
- Induction hardened raceways; geared versions available with induction hardened teeth
- Matching pinions available for all standard bearings
Capacities
| Thrust | 7,000 to 1,100,000 lb |
|---|---|
| Moment | 1,400 to 390,000 ft-lb |
| Radial | 400 to 150,000 lb |
21 Series part numbers
| SlewPro part | Series | Gear | Raceway (mm) | OD (mm) | ID (mm) | Height (mm) | Weight (lb) | Crosses to |
|---|
New 21 Series designs are added often. Don't see your size? Tell us your application and we will design it, with no engineering charge. The mounting surface must conform to defined standards for flatness and strength; contact us for help sizing this bearing.
Engineering guides
Practical articles from our engineers on specifying, installing and maintaining these parts.
Inside the Single-Row Ball Slewing Bearing: The Engineering Behind the Workhorse
Single-row four-point contact ball slewing bearings handle combined axial, radial, and moment loads in one compact row — but only when speci
Read the guide →Why We Won't Sell You a Single-Row Ball Bearing That's Almost Right
When a standard single-row ball slewing bearing almost fits the application, SlewPro engineers push back before they push product. Here's wh
Read the guide →Single Row vs. Double Row Ball Slewing Bearings: How to Know When to Upgrade
Learn when double row ball slewing bearings justify their cost premium over single row designs. Expert comparison of load capacity, envelope
Read the guide →Slewing Ring Bearing Installation and Maintenance: A Practical Checklist
How to store, mount, bolt, check and maintain a slewing ring bearing: the steps that prevent early failure, in the order you do them.
Read the guide →Talk to an engineer
Need help selecting the right part? Our engineers will size it, cross it, and quote it — usually within 1–2 business days.
Not in the catalog? We design to your application, with no engineering charge.