For Type F, no radius in the fllet contour shall be less than R1 minimum specified in Table 4. Tags: Flange Head Screws. ASME A ASME standards. IEC standards. Question: Phrase the question as a request for an interpretation of a specific requirement suitable for general understanding and use, not as a request for an approval of a proprietary design or situation. The inquirer may also include any plans or drawings that are necessary to explain the question; however, they should not contain proprietary names or information.
Requests that are not in this format may be rewritten in the appropriate format by the Committee prior to being answered, which may inadvertently change the intent of the original request. ASME procedures provide for reconsideration of any interpretation when or if additional information that might affect an interpretation is available.
Attending Committee Meetings. The B18 Standards Committee regularly holds meetings, which are open to the public. Persons wishing to attend any meeting should contact the Secretary of the B18 Standards Committee.
Where specified, the on which dimensional data are based, and a specification minimum body length L B , min. Where questions arise concerning acceptance of product, the dimensions in the tables shall govern over grip gaging length, LG: the distance measured parallel to recalculation by formula. Heavy hex structural bolts, the axis of the bolt or screw from the underhead bearing formerly covered in ASME B The maximum 1.
Standard is not intended to imply that all of the products described herein are stock production sizes. Consumers point length: the length from the pointed end to the first should consult with suppliers concerning lists of stock fully formed thread at major diameter as determined production sizes. Since these are inch fastener standards, there are no thread length: the length from the extreme point of the comparable ISO standards.
For 1. When plating or coating is specified, the finished product dimensions transition thread length, Y: the length that includes the shall be as agreed upon between supplier and purchaser. Where preceding the decimal and zeros in the fourth decimal specified, transition thread length is a reference dimen- place shall be omitted.
Symbols specifying geometric characteristics are in For definitions of terminology not specified in this accord with ASME Y ASME B1. Publisher: The American Society of Mechanical 2. Box maximum width across flats or lobes. For reference pur- , Fairfield, NJ www.
Die seams on the Discontinuities of Bolts, Screws, and Studs, Inch and body and all other styles of screws that exceed the body diame- Metric Series ter are not permitted. The www. The presence Externally Threaded Fasteners of a point is to reduce the possibility of damage to the leading threads and promote assembleability with a Publisher: Society of Automotive Engineers SAE tapped hole or nut.
Point features not defined in a given International , Commonwealth Drive, product standard are at the discretion of the Warrendale, PA www. Threads on all products in Unless otherwise specified, bolts and screws shall be this Standard, except lag screws, shall meet the require- supplied with a plain as processed finish, unplated, ments of ASME B1.
Lag screw thread dimensions are or uncoated. Light oil on the surface is permissible to specified in Table Unless otherwise specified, size limits for standard external thread Class 2A apply prior 2.
The external thread allowance may be used to Surface discontinuities shall be in accordance with the accommodate the coating thickness on plated or coated requirements of the applicable fastener material stan- parts, provided that the maximum coating thickness is dard.
The purchaser may specify additional surface dis- no more than one-fourth of the allowance. Thus, the continuity requirements for screws and bolts when thread after plating or coating is subject to acceptance tighter control of surface discontinuities is required or using a basic size Class 3A GO size thread gage and a when discontinuity limits are not specified in the appli- Class 2A NOT GO size thread gage.
Thread series on all bolts and 2. The major diam- or two-place decimal equivalent ; material, including eter of incomplete thread shall not exceed the actual specification where necessary; and protective finish, if major diameter of the full form thread. For bolts and screws 2. Identification mark- 24 in. When raised, the height of the marking may not exceed 2. When indented, the the threaded end. Unless otherwise specified by the pur- depth of the marking shall not reduce the load-carrying chaser, the drill size and depth shall be in accordance capacity of the fastener.
Each of the products 2. Each of the products ble notes, are required, the purchaser must clearly spec- included in this Standard shall be marked in accordance ify them in the purchase documents. R LT nom. F 25 deg LG See para. L approx. L See para. Diameter Max. Basic Max. This to identify its source, manufacturer, or private label is not applicable to askew head bolts. When specified by are presented in Tables 1 through 4, respectively.
Upon completion of the machining, all dimensions and geo- 3. For askew head bolts, see Note 1 threads. LG See para. S LT nom. Diameter Length, S [Note 2 ] Max. A die seam across the bearing surface is permissible. Angle of bearing surface with respect to shank is based on the 2 in. Askew head bolts are only available with unified course UNC threads. Midheight, H, is a reference dimension and equals the basic head height of square bolts as given in Table 2. All askew head bolts of nominal lengths equal to or shorter than the nominal thread length, LT, plus the unthreaded length, S, shall be threaded for full length.
The distance from the bearing surface of the head, as measured at midheight of head to the last scratch of thread, shall not exceed the unthreaded length, S. Up to 1 in. All bolts of nominal lengths equal to or shorter than c 0. The diameter of the unthreaded length on bolts that 3. Other materials and grades 3. When specified by the purchaser, bolts may be sup- 3. These shall have a body diameter of not less than the minimum pitch For additional requirements, see sections 1 and 2.
Top of e 0. Top of Bolt length tolerances are given in Table 5. If full form, the top of head shall be 3. Thickness of the washer face shall be not less than The length of thread on bolts shall be controlled by 0. The maximum grip gaging and smaller and not less than 0. The washer face is places for any bolt not threaded full length, shall be not applicable to hex flange or lobe head screws. Mea- of minus a length equal to five coarse thread pitches.
For bolts that are threaded full length, LG, max. Measurement of FIM shall for sizes larger than 1 in. It shall be used as the criterion be made as close to the periphery of the bearing surface for inspection.
LT nom. Y nom. Height, J Shorter 6 in. Reference See Para. See Para. Height, J Nom. Wrenching height is a distance measured from the bearing surface up the side of the head at the corners.
The width across corners shall be within specified lim- its for the full wrenching height. Bearing Surface 6 in. Ring B shall be placed on the screw head followed by Ring T. The head is acceptable if ring T does not contact ring B after both rings are in place on the head. Radius, R2, applies both at the corners and at the flats of the hexagon.
The contour of edge at flange periphery, between the maximum flange diameter, B, max. R, min. Lf, max. Other linishes, where required, shall be subject to agreement between the manufacturer au ci purchaser. Recommended p cticcs covering the preparation of holes for installation of taper pins are contained in Nonmandatory Appendix A.
See the following examples: 1 Pin. Taper Commercial Class No. Taper Precision Class 0. Steel, Zinc Plated 4. The outer periphery of hardened groi nd machine dowel pins shall con form to true round about the longitudinal axis of the pin within 0.
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