Radial Ball Bearings
(See also: SRDG Cartridge Bearings)

Radial ball bearings are probably the most widely used and most recognized ball bearing. These bearings have one row of balls (referred to as a single row), that revolves around the ball path. This feature provides another name for the bearings, they are commonly called deep groove ball bearings. Although designed to primarily carry radial loads, a radial ball bearing’s raceways are deep enough that it can also carry reasonable thrust loads. (However, if thrust loads are excessive, an alternative type of bearing should be considered.)

Conrad Bearing

Most ball bearings, including single row, deep groove ball bearings (SRDG), are assembled using the Conrad method of construction. As an historical note, the inventor of this bearing assembly procedure, Robert Conrad, was given British patent no. 12,206 back in 1903, and U.S. patent no. 822,723 in 1906. This method of construction first takes an inner ring and outer ring and places the inner ring inside of the outer. With the rings oriented in the same direction, the inner is positioned so that it touches the outer ring at one point. This creates a crescent-shaped open area between the rings where the proper number of balls of the appropriate size are placed. The inner ring is then snapped into its proper position in relationship to the outer ring. The balls are evenly distributed around the raceway and the retainer is assembled or inserted into place.

Radial ball bearings are designed to carry primarily a radial load. When a pure radial load is applied to the bearing, the balls settle to the deepest point of the raceways and the load is transferred through the rings and balls where they contact one another. These points of contact created within the bearing will be perpendicular to the shaft.

The SRDG ball bearings are most commonly used in motors, hand tools, fans, etc., and are widely used for their versatility and durability. NTN’s designation for these types of bearings is a 6 in the first position of a three (3), or four (4) digit base bearing number.

Examples of the NTN SRDG Ball Bearing Series

Maximum Capacity SRDG Ball Bearings

These bearings are identical to the SRDG described above with one exception: they are wider so as to accommodate more grease. They are, in fact, the same width as the double row angular contact bearings to be covered later in this section. NTN's designation for this type of bearing is 63 in the first two positions of a five (5) digit base bearing number.

Examples of the NTN SRDG Cartridge Bearing Series

The 8000 Series Ball Bearings

Angular Contact Ball Bearings