BALL BEARING SLIDE-

The fit requirements of a ball bearing slide product present special problems for roll forming the components. A simple slide product might look like the one illustrated in Fig. 8.1:

Fig. 8.1

MATERIAL TOLERANCE EFFECTS-

If the two components are rolled from 16 ga. (.0598) cold rolled steel, the commercial tolerance for the thickness would be .002 , which has a pretty considerable impact on the quality of the fit. The detail drawing of the inner channel with dimensional tolerances that necessarily result from the thickness tolerance of the material would be as shown in Fig. 8.2:

Fig. 8.2

If tool adjustments were made in response to changes in material thickness, the 1.630 distance between ball races would vary by .004, and the height location of the ball races of .223 would vary by .002. Fig. 8.3 shows the final pass of the inner channel with the upper roll and the side rolls adjusted to the maximum stock thickness of .062, and the distance between the ball races which results is seen to be 1.634. The height of the ball race center is increased by .002 to .225. Holding the material gap uniform at .062 through the ball race element requires the reduction of the radius of the side rolls to .133.

Fig. 8.3

The detail drawing of the outer channel with dimensional tolerances that necessarily result from the thickness tolerance of the material would be as shown in Fig. 8.4:

Fig. 8.4

INTERFERENCE FIT AT MAXIMUM t-