ASME B18.16M:2004 pdf download Prevailing- Torque Type Steel Metric Hex Nuts and Hex Flange Nuts Revision and Consolidation of ASME B18.16.1M, B18.16.2M, . and B18.16.3M
4 TERMINOLOGY
For definitions of terms relating to fasteners or com-ponent features thereof used in this Standard, refer toASME B18.12.Unless otherwise noted, all references to nuts in thisStandard mean prevailing-torque hex nuts and hexflange nuts.
5 DIMENSIONS
Unless otherwise stated, all dimensions in this Standard are in millimeters (mm), and apply before any plating or coating. When a plating or coating is specifiedthe finished product dimensions shall be as agreed uponbetween supplier and purchaser.
Symbols specifying geometric characteristics are inaccord with ASME Y14.5M
6 NUT DESIGNS AND PROPERTY CLASSES
There are three basic designs for prevailing-torque
nuts.
(a) all-metal, one-piece construction nuts which de-rive their prevailing-torque characteristics from con-trolled distortion of the nut thread and/or body
(b) metal nuts which derive their prevailing-torquecharacteristics from the addition or fusion of a nonmetallic insert, plug, or patch in their threads
(c) top insert, two-piece construction nuts which derive their prevailing-torque characteristics from an insert, usually a full ring of nonmetallic material, locatedand retained in the nut at its top surface
The two nut designs defined in paras. 6(a) and (b)have the same dimensional requirements and are designated “all-metal type” in Tables 1 and 2. Nut design6(c) is designated “top insert type” in Tables 1 and 2.
Property classes 5,9, and 10 nuts have mechanical andperformance properties as specified in Table 3.
7 WIDTH ACROSS FLATS
The width across flats shall be the distance measuredperpendicular to the axis of the nut, between two opposite wrenching flats. The maximum width across flatsmay be exceeded by 0.05 mm to allow for nut defor-mation caused by introduction of the prevailing-torquefeature The width across flats and width across cornersmay be less than the specified minimum in the deformedportion of the nut containing the prevailing-torque fea-ture.
At maximum material condition the axis of the hexagon shall be located at true position with respect to theaxis of the thread pitch diameter within a tolerance zonehaving a diameter equivalent to 4% of the maximumwidth across flats.
8 THICKNESS
The nut thickness shall be the overall distance, meas.ured parallel to the axis of the nut, from the top of thenut to the bearing surface of hex nuts, and to the planeof the bearing circle diameter of hex flange nuts Raisedidentification markings, if present, shall be excluded.
9 WRENCHING HEIGHT
The wrenching height is the distance, measured at acorner of the hex, from the bearing surface of hex nuts,and from the junction of the hex portion with the flangeof hex flange nuts to the last plane of full formed hexi.e, the plane perpendicular to the nut axis that is clos-est to the top of the nut and at which the width acrosscorners is within its specified limits. Wrenching heightfor hex nuts is dimension M, in Table l, and is subjectto measurement. Wrenchine heieht for hex flange nutsis dimension T in Table 2 and is controlled by the gaging requirement specified in para. 10.