一種通常呈圓形的剛性部件,用於容納軸承。它用於定位軸承,但不會包裹軸承或限制軸承的運動。
1.2200 inches minimum and 1.2400 inches maximum outside diameter, 0.0600 inches minimum and 0.0630 inches maximum overall width, 0.7520 inches minimum and 0.7620 inches maximum bore diameter, steel overall material, flat race surface style designator