Bearing Lubrication

The primary purpose of lubrication is to establish a load carrying film on the component parts of the bearing so that metal to metal contact is avoided between the rolling elements. Lubrication also acts as an inhibitor to corrosion and assists in the sealing process. Appropriate lubrication selection must be based on the critical criteria (speeds, loads, temperatures, etc.) of the bearing application.

Grease Lubrication

Grease of a #2 consistency with an EP (extreme pressure) additive is the preferred lubricant in most normal applications. All Craft Cartridges have a grease fitting, allowing the lubricant direct access to the rolling surfaces of the bearing. Depending on the application, excessive grease will result in an abnormal rise in bearing temperature. Therefore, Craft Cartridges are also supplied with purging capabilities. This is done by removing the purge plug, located in the lower half of the cartridge, and allowing the grease to seek its own level. Once this is accomplished, the plug is then replaced.

Greasing Capacity

All bearing component parts should be cleaned and free of preservatives and contaminants. As the component parts of the bearing are assembled around the shaft, they should be hand coated with grease. The bearing should never be assembled dry and the lubricant injected after the unit is mounted. As a general guide, grease should be applied based on the following chart.

Dn Percentage of Packing
(RPM x Shaft Size) (See chart, Grease Capacity)
0 to 2000 100%
2000 to 4000 75%
4000 to 6000 50%
6000 to 8000 33%
8000 and up 25%

Greasing Schedules

Held Bearing (Locating) Due to the cycloidal action of the rollers against the flanges of the clamping collars and the shoulders of the outer raceway, the Held Bearing requires a more frequent lubrication schedule than the Float Bearing. Every 250 operating hours, or at two-week intervals, the bearing should get three to four shots of grease (1/2 oz.), with a suggested yearly thorough cleaning and re-lubrication.

Float Bearing (Non-locating) Every 500 hours, or at one month intervals, the bearing should get three to four shots of grease, with a suggested yearly thorough cleaning and re-lubrication.

The above greasing schedule is for reference only, and may be modified to accommodate the application. Experience will determine the best interval for each application.

Oil Lubrication

Oil lubrication may be required in applications where extreme speed, high axial load, temperature, and/or other operating conditions may be a factor. To insure proper selection and utilization of oil lubrication, please contact Craft Bearing’s Engineering Department.

Note: Axial capacity and maximum RPM may be reduced when extreme pressure grease or oil lubrication is not used.


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