identified by the absence of grease fittings. The grease used will ordinarily maintain its lubricating qualities for the life of the bearing under normal operating conditions. Where high operating temperatures are encountered, the life of the bearing may be limited to the time the lubricant will last, Ball bearings consume only a very small amount of lubricant, but enough must be present at all times to avoid injuries. The length of time a bearing can run without having grease added or replaced will depend upon the operating conditions. Use a high grade neutral mineral grease composed of a soda soap base and a clean refined mineral oil. or specifications. Do not mix greases of different types A satisfactory grease should have the following qualities: 1. Freedom from abrasive matter such as grit, tale, mica, clay or fillers of any kind, 2. Freedom from corrosive substances such as free lime, iron oxide, ete. 3. Freedom from acid, alkali, and moisture, 4. At operating temperature, a consistency low enough to prevent, excessive channeling yet high enough to avoid fluidity which mn . would create churning or leakage, The least possible tendency to change consistency such as hardening, thickening, or separation into oil and soapy matter. 6. A melting point considerably higher than the operating temperature. 3-31