General

The information provided in this section is quite general and is intended primarily to indicate what must be considered by machine and equipment designers to facilitate bearing mounting and dismounting. For additional information about mounting and dismounting procedures, refer to the SKF bearing maintenance handbook.
Where to mount
Bearings should be mounted in a dry, dust free area away from machines producing swarf and dust. When bearings have to be mounted in an unprotected area, which is often the case with large bearings, steps should be taken to protect the bearing and mounting position from contaminants like dust, dirt and moisture. This can be done by covering or wrapping bearings and machine components with plastic or foil.
Preparations prior to mounting or dismounting
Prior to mounting, be sure all the necessary parts, tools, equipment and data are readily available. It is also advisable to review any drawings or instructions to determine the correct order and direction that components are to be assembled. Leave the bearings in their original packages until immediately prior to mounting so that they are not exposed to any contaminants. If there is a risk that the bearings have become contaminated due to improper handling or damaged packaging, they should be washed and dried prior to mounting.

Checking associated components

Housings, shafts, seals and other components of the shaft system should be checked to make sure that they are clean. This is particularly important for threaded holes, lead-ins or grooves where remnants of previous machining operations might have collected. Also, be sure that all unpainted surfaces of cast housings are free of core sand and that any burrs are removed.

When all components have been cleaned and dried, check the dimensional and form tolerances of each piece. The bearings only perform satisfactorily if the associated components comply with the prescribed tolerances. The diameters of cylindrical shaft and housing seats are usually checked with a micrometer or internal gauge at two cross-sections and in four directions (fig. 1). Tapered shaft seats can be checked using a ring gauge (GRA 30 series), a taper gauge (DMB or 9205 series) or a sine bar.

It is advisable to keep a record of all measurements. When measuring, it is important that the components and the measuring instruments are approximately the same temperature. This is particularly important for large bearings and their associated components.

Removing the preservative

Normally, the preservative applied to new bearings does not need to be removed. It is only necessary to wipe off the outside and bore surfaces. However, if bearings are to be grease lubricated and used at very high or very low temperatures or if the lubricant to be used is not compatible with the preservative, the bearing should be washed and dried carefully. Bearings capped with seals or shields are filled with grease and should not be washed prior to mounting.

When taken from its original packaging, some large bearings with an outside diameter D > 420 mm may be covered with a relatively thick, greasy layer of preservative. These bearings should be washed thoroughly with white mineral spirits or other safe cleaning fluid, and dried.
Bearing handling
SKF recommends using gloves as well as carrying and lifting tools (fig. 2) that have been specially designed for handling bearings. Using the proper tools enhances safety while saving time and effort.

When handling hot or oily bearings, SKF recommends wearing the appropriate heat or oil resistant gloves.

For large, heavy bearings, lifting tackle that supports the bearing from the bottom should be used (fig. 3). A spring between the hook and tackle can facilitate positioning the bearing onto the shaft.

To ease lifting, large bearings can be provided, on request, with threaded holes in the ring side faces to accommodate eye bolts. These holes are designed to accommodate only the weight of the bearing, because the size and depth of the hole is limited by the ring thickness. Make sure that the eye bolts are only subjected to load in the direction of the shank axis (fig. 4).

When mounting a non-split large housing over a bearing that is already in position on a shaft, it is advisable to provide three-point suspension for the housing, and for the length of one sling to be adjustable. This facilitates the process of aligning the housing bore with the bearing outer ring.
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