scope:

The scope of this standard deals with shank diameters of fasteners and holes to be used with such fasteners. It is the result of considerable study made by the NASC and offers advantages to the producers and consumers of cylindrical shaped items. It is aimed toward providing a greater degree of standardization of

a. The fastener products

b. Interchangeable usage of similar products

c. The hole sizes and limits

d. The shank diameters, fillet radii and limits

e. The resultant fits

f. The tooling, gages, etc. to produce the products

g. The drills, reamers, etc. to produce the holes

h. The interchange of design and manufacturing between companies

Although economic benefit can be achieved in this particular area, the standard does not cover all possible requirements which may exist for cylindrical shaped parts and fits in other areas. If applicable, however, its use is to be encouraged. The hole size and fillet radius portion of this standard should be especially considered "recommended practice" as it is each company's prerogative to determine a convenient change period for incorporation of all the data or portions thereof in their designs.