Slew Bearing – What It Is, Types, Applications & Manufacturer in India

If you are searching for a slew bearing and finding pages that also use the terms "slew ring bearing," "slewing bearing," or "turntable bearing" — they all refer to the same product. The name "slew bearing" is simply a shortened form that engineers and procurement teams commonly use in daily communication. This guide from Kavitsu Robotronix, a leading slew bearing manufacturer based in Satara, India, explains everything you need to know about slew bearings in one place.

What Is a Slew Bearing?

A slew bearing is a large-diameter rolling element bearing that enables continuous 360-degree rotation between two heavy structures while simultaneously supporting combined loads from multiple directions. Unlike a standard small bearing that handles only one type of load (axial or radial), a slew bearing handles all three load types at once:

• Axial load — the vertical force pressing down or pulling up (e.g. the weight of a crane boom)
• Radial load — the horizontal force pushing sideways (e.g. wind pressure against a structure)
• Moment load — the overturning or tipping force created when a load is offset from the centre (e.g. an extended excavator arm)

This combined load capability, delivered through a thin, flat ring-shaped body, is what makes slew bearings indispensable in cranes, excavators, wind turbines, and hundreds of other heavy-duty rotating machines.

All the Names for a Slew Bearing

How Does a Slew Bearing Work?

A slew bearing consists of two main steel rings — an inner ring and an outer ring — with rolling elements (balls or rollers) placed between them in a precision raceway. One ring is bolted to the fixed structure (e.g. the machine frame or foundation), and the other ring is bolted to the rotating structure (e.g. the crane superstructure or excavator upper body).

When the machine rotates, the rolling elements move smoothly through the raceway, allowing the two rings to rotate relative to each other while supporting the full load from all directions. Gear teeth cut into one of the rings allow a drive motor and pinion to power the rotation precisely.

The result: a single flat ring component that can rotate an entire crane, excavator body, or wind turbine nacelle — structures weighing hundreds of tonnes — with exceptional precision and minimal friction.

Types of Slew Bearings

By Rolling Element

• Single Row Ball Slew Bearing — a single row of steel balls in a four-point contact raceway. Most compact, most common. For light to medium loads. Used in solar trackers, light cranes, vehicle turntables.
• Double Row Ball Slew Bearing — two parallel rows of balls for higher moment load capacity. For medium to heavy loads. Used in passenger boarding bridges, vehicle turntables, medium cranes.
• Three Row Roller Slew Bearing — three rows of cylindrical rollers in separate raceways, one for axial load (each direction) and one for radial load. Highest load capacity of all slew bearing types. Used in ship cranes, offshore platforms, large excavators.

By Gear Configuration

• External gear slew bearing — gear teeth on the outer circumference; pinion drive mounts outside. Easy maintenance access.
• Internal gear slew bearing — gear teeth on the inner ring; pinion sits inside the bore. More compact, protected gear from contamination.
• Non-gear slew bearing — no gear teeth; rotation driven by an external mechanism such as hydraulics or a chain.

Slew Bearing Technical Specifications

Where Are Slew Bearings Used?

• Cranes — the slew bearing (also called the slewing ring) is the primary rotational joint between the crane superstructure and undercarriage, enabling full 360° crane rotation
• Excavators — the swing bearing or slew bearing connects the excavator upper body to the undercarriage, allowing the machine to rotate in any direction
• Wind turbines — one large slew bearing (the yaw bearing) rotates the nacelle to face the wind; separate pitch bearings on each blade adjust blade angle
• Solar trackers — slew bearings and slew drives rotate solar panels to follow the sun, increasing energy output by 20–40%
• Mining equipment — stackers, reclaimers, bucket wheel excavators use large slew bearings for their primary rotation
• Offshore and marine — ship cranes, offshore drilling platforms, pipe-laying vessels, and anchor winches
Radar and satellite — high-precision slew bearings position radar antennas, satellite dishes, and telescopes
• Industrial turntables — vehicle inspection turntables, heavy-load rotating platforms, stage equipment

Slew Bearing vs Slew Drive — Key Difference

A common question when sourcing slew bearings is whether you need a slew bearing or a slew drive. Here is the simple distinction:

• A slew bearing is a passive component — it supports the load and allows rotation, but does not power the rotation. You need a separate motor, pinion gear, and drive system.
• A slew drive is a complete powered assembly — it combines a slew ring bearing with a worm gear, motor interface, and self-locking mechanism in one sealed unit. It both supports the load and powers the rotation.

Choose a slew bearing when you already have a drive mechanism or need a very large diameter. Choose a slew drive when you need compact, self-contained powered rotation with self-locking.

Kavitsu Robotronix – Slew Bearing Manufacturer in India

Kavitsu Robotronix Pvt. Ltd. is based in Satara, Maharashtra and has manufactured slew bearings for over 30 years. Our slew bearings are used by 4,635+ customers across India and exported to 30+ countries including Germany, USA, UAE, Australia, Singapore, and South Korea.

• Bore diameter: 100mm to 4,000mm+ (custom available)
• Single row ball, double row ball, and three row roller types
• Internal gear, external gear, and non-gear configurations
• Material: 42CrMo alloy steel with induction-hardened raceways
• Export with full documentation: material test certificates, dimensional inspection reports, certificate of origin
• Custom slew bearings to your drawing or specification

Frequently Asked Questions