Unground bearings are made from stamped metal plates. Assembled bearings have poor internal tolerances on the raceways. Usually, they include a full complement of balls without a ball retainer. This means the balls can collide with each other and are not evenly spaced around the bearing. They are very cost effective but generally do not have a long service life. They are best used for light loads and low speeds.
Crimped bearings are constructed with two metal plates stamped together to create the outer raceway and body of the bearing at the same time. To be installed the tube must be deformed down around the body of the bearing or “crimped”. Once the tube has been crimped the bearings cannot be replaced by new bearings. All bearings in this category have flanges and cannot be recessed.
