Scope and Application.
This standard presents definitions of terms applying to fits between plain (non-threaded) cylindrical parts and makes recommendations on preferred sizes, allowances, tolerances, and fits for use wherever they are applicable. The standard through 20 in. diameter is in accord with the recommendations of American-British-Canadian Conferences. Experimental work is being carried on and when results are available, agreement in the range above 20 in. will be sought. It represents the combined thinking and experience of groups who have been interested in standards in this field, and it should have application for a wide range of products. The recommendations, therefore, are presented for guidance and for use where they might serve to improve and simplify products, practices, and facilities.
Many factors, such as length of engagement, bearing load, speed, lubrication, temperature, humidity, surface texture, and materials, must be taken into consideration in the selection of fits for a particular application, and modifications in these recommendations might be required to satisfy extreme conditions. Subsequent adjustments might also be desired as the result of experience in a particular application to suit critical functional requirements or to permit optimum manufacturing economy. Selection of departure from these recommendation will depend upon consideration of the engineering and economic factors that might be involved.