ASME B18.2.1:2010 pdf download

ASME B18.2.1:2010 pdf download.Square, Hex, Heavy Hex, and Askew Head Bolts and Hex, Heavy Hex, Hex Flange, Lobed Head, and Lag Screws (Inch Series)
1.1 Scope
1.1.1 This Standard covers the dimensional requirements for nine product types of inch series bolts and screws recognized as American National Standard. Also included are appendices covering gaging proce- dures, grade markings for bolts and screws, formulas onwhichdimensionaldata are based, anda specification to assist in identifying a product as being a screw or a bolt. Where questions arise concerning acceptance of product, the dimensions in the tables shall govern over recalculation by formula. Heavy hex structural bolts, formerly covered in ASME B18.2.1, are now covered in ASME B18.2.6. 1.1.2 The inclusion of dimensional data in this Standard is notintended to imply that all ofthe products described herein are stock production sizes. Consumers should consult with suppliers concerning lists of stock production sizes.
1.5 Terminology
As used in this Standard, “shortbolt” or “shortscrew” means a bolt or screw of a diameter-length combination that is required to be threaded for full length, whereas “long bolt” or “long screw” means a bolt or screw of a diameter-length combination that is not threaded for full length. body length, L B : the distance measured parallel to the axis of the bolt or screw from the underhead bearing surface to the last scratch of thread or, for rolled threads, to the top of the extrusion angle. Where specified, the minimum body length (L B , min.) is a criterion for inspection. grip gaging length, L G : the distance measured parallel to the axis of the bolt or screw from the underhead bearing surface to the face of a noncounterbored, noncount- ersunk standard GO thread ring gage assembled by hand as far as the thread will permit. The maximum grip gaging length (L G , max.) is a criterionfor inspection. point length: the length from the pointed end to the first fully formed thread at major diameter as determined by the distance that the point enters into a cylindrical NOT GO major diameter ring gage (refer to Gage 3.1 in ASME B1.2). thread length: the length from the extreme point of the bolt or screw to the last complete (full form) thread. For bolts and screws in this Standard, other than lag screws, the nominal thread length (L T ) is a reference dimension intended for calculation purposes only. transition thread length, Y: the length that includes the length of incomplete threads, the extrusion angle on rolled threads, and tolerances on grip length. Where specified, transition thread length is a reference dimen- sion intended for calculation purposes only. For definitions of terminology not specified in this Standard, refer to ASME B18.12.
2 GENERAL DATA FOR BOTH BOLTS AND SCREWS
2.1 Heads 2.1.1 Top of Head. Top of head shall be full form andchamfered,withthe diameterofchamfercircleequal to the maximum width across flats, on square or hex head products and the “B” dimension shown in Table 11 for lobed head screws with a tolerance of −15%. 2.1.2 Width Across Flats. The width across flats of head shall be the overall distance measured perpendicu- lar to the axis of product between two opposite sides of the head in accordance with the notes in respective dimensional tables. 2.1.3 Head Height. The head height shall be the overall distance measured parallel to the axis of product from the top of the head to the bearing surface and shall include the thickness ofthe washer face where provided. 2.1.4 Position of Head. The runout of the flats or lobes of the head shall be no greater than 6% of the maximum width across flats or lobes. For reference pur- poses, the evaluation shall be made by indicating on the flats or outer surface of lobes while holding the body one bolt diameter from under the head and rotating the part. 2.2 Bolt or Screw Length The bolt or screw length shall be the distance mea- sured parallel to the axis of product from the bearing surface of the head to the extreme end of the bolt or screw, including the point if the product is pointed.