ASME B18.5-2008 pdf free download.Round Head Bolts (Inch Series)
2 GENERAL DATA
2.1 Heads
2.1.1 Height of Head. The height of head shall be measured, parallel to the axis of bolt, from the top of the head to the bearing surface for flat bearing surface type heads, and from the top of the head to the point of intersection of the conical bearing surface of the head with the flat ofsquare neck or the body diameter, which- ever is applicable for countersunk heads.
2.1.2 Head Periphery. Because the heads on these products normally are not machined or trimmed, the circumference may be somewhat irregular and the edge may be rounded or flat.
2.1.3 Underhead Fillets. All bolts having flat bear- ing surface type heads shall have a definite fillet at the junction of head and shank. The minimum radius of fillet shall be equal to one-half of the maximum values specified in the respective dimensional tables. The radius offilletshall notexceed the values specified in the respective dimensional tables except for bolts produced from nonferrous and corrosionresistant materials, on which maximum fillets shall be subject to agreement between manufacturer and purchaser.
2.2 Square Neck
2.2.1 Depth of Square. The depth of square shall be measured, parallel to the axis of bolt at the midpoint of the flats of square, from the bottom of square to the bearing surface for bolts having flat bearing surface type heads, and to the intersection of flats of square with the conical bearing surface for bolts having countersunk heads.
2.2.2 Corners ofSquare. The corners of square neck may be rounded to the extent specified in the respective dimensional tables and need not be filled out for the total depth of square.
2.3 Body Diameter
2.3.1 Full Diameter Body. Unless otherwise speci- fied, all bolts covered by this Standard, except round head square neck bolts and round head short square neck bolts, will be furnished with full diameter body of limits given in the dimensional tables.
2.3.2 Round Head SquareNeckand Round Head Short Square Neck Bolt Diameter Body. Unless otherwise specified, round head square neck bolts and round head short square neck bolts shall be furnished with a body diameter having a maximum limit equal to that of the full diameter body and a minimum limit equal to the minimum pitch diameter of the thread as given in the dimensional tables.
2.3.3 Swell or Fin. A swell or fin under the head or under corners of square neck shall be permissible, provided it does not affect serviceability, nor exceed the basic bolt diameter by more than the following: (a) 0.030 in. for sizes up to and including 1 ⁄ 2 in. (b) 0.050 in. for sizes over 1 ⁄ 2 in. to 3 ⁄ 4 in., inclusive (c) 0.063 in. for sizes over 3 ⁄ 4 in. to 1 1 ⁄ 4 in., inclusive (d) 0.093 in. for sizes over 1 1 ⁄ 4 in. 2.4 Length 2.4.1 Measurement. The length of the bolt shall be measured, parallel to the axis of the bolt, from the end of the bolt to the bearing surface for bolts having flat bearing surface type heads, and to the top of the head for bolts having countersunktype heads.
2.4.2 Tolerance on Length. The tolerance on length of bolts shall be as tabulated below.
2.4.3 Straightness. The length of any permissible swell on the body under the head or neck of bolts shall be excluded from checks for shank straightness. A sug- gested gage and a gaging procedure for checking straightness are shown in ASME B18.2.9.
2.5 Threads Uncoated threads shall be Unified coarse (UNC or UNRC Series), Class 2A, in accordance with ASME B1.1. Coated threads shall be accepted based on3A highlimits and 2A low limits. Unless otherwise specified, gaging for screw thread dimensional acceptability shall be in accordance with Gaging System 21 as specified in ASME B1.3M.
2.6 Length of Thread
2.6.1 Measurement. The length of thread shall be measured, parallel to the axis of the bolt, from the end of the bolt to the last complete (full form) thread.
2.6.2 Minimum Thread Length. The minimum length of thread shall be equal to twice the basic bolt diameter plus 0.25 in. for nominal bolt lengths of 6 in. or shorter, and twice the basic bolt diameter plus 0.50 in. for longer nominal lengths.ASME B18.5 pdf download.ASME B18.5-2008 pdf free download
