ASME B18.2.1:2012 pdf download

ASME B18.2.1:2012 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 on which dimensional data are based, and a 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 not intended to imply that all of the products described herein are stock production sizes. Consumers should consult with suppliers concerning lists of stock production sizes.
1.2 Comparison
With ISO Standards Since these are inch fastener standards, there are no comparable ISO standards.
1.3 Dimensions
All dimensions in this Standard are in inches and apply to unplated or uncoated product. When plating or coating is specified, the finished product dimensions shall be as agreed upon between supplier and purchaser. Where nominal sizes are expressed in decimals, zeros preceding the decimal and zeros in the fourth decimal place shall be omitted. Symbols specifying geometric characteristics are in accord with ASME Y14.5.
1.4 Options
Where specified, options shall be at the discretion of the manufacturer unless otherwise agreed upon by the manufacturer and purchaser.
1.5 Terminology
As used in this Standard, “short bolt” or “short screw” 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 the appropriate noncounterbored, noncountersunk special GO thread ring gage, assembled by hand as far as the thread will permit. The maximum grip gaging length, L G , max., is a criterion for 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.
2.1 Heads
2.1.1 Top of Head. Top of head shall be full form and chamfered, with the diameter of chamfer circle equal to the maximum width across flats, on square or hex head products and the “B” dimension shown in Table 9 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.