ASME B18.16M-2004 pdf free download.Prevailing-Torque Type Steel Metric Hex Nuts and Hex Flange Nuts.
ASME B18.16M covers the complete general, dimensional. mechanical, and performance data for metric prevailing-torque hex nub and hex flange nub of prop’ erty classes 5,9, and 10 as defined in ASTM A563M.
The inclusion of dimensional data in this Standard is not intended to imply that all of the nut sizes in conjunction with the various options described herein arc stock items. Consumers should consult with suppliers concerning lists of stock production prevailing-torque hex and hex flange nuts.
2 COMPARISON WITH ISO STANDARDS
2.1 CoordinatIon With ISO Standards
I lex and hex flange nuts as covered in this Standard have been coordinated to the extent possible with ISO
2320,1507040, 1507041, ISO 7042. ISO 7043,1507044, ISO 7719, and ISO 7720. The dimensional differences are few, except those of the M1() size. None affect the functional interchangeability of nuts manufactured to the requirenwnts of either. The clamp torque values in Table 4 of this Standard are significantly different compared to the applied torques in ISo 2320 Annex C. ISo 2320 does not make any coating distinctions.
2.2 Letter Symbols
Letter symbols designating dimensional characteristics are in accord with those used in ISO) standards, except that capitaLs have been used instead of lower case letters used in ISO standards.
2.3 ISO Width Across Flats
M10 hex and hex flange nuts with 15mm width across flats an currently being produced and used In the US and many other countries. This width across flats is not ISO standard for hex nuts, hut is ISO standard for hex flange nuts. The ISO standard for M10 hex nuts sped- flex 16mm width across flats. Unless M10 hex nuts with 15mm width across flats are specifically ordered, MW hex nuts with 16 mm width across flats shall be furnished.
7 WIDTH ACROSS FLATS
The width across flats shall be the distance, measured perpendicular to the axis of the nut, between two opposite wrenching flats. The maximum width across flats may be exceeded by 0.05 mm to allow for nut deformation caused by introduction of the prevailing-torque feature. The width across flats and width across corners may be less than the specified minimum in the delornied portion of the nut containing the prevailing.torque lea. ture.
At maximum material condition the axis of the hexagon shall be located at true position with respect to the axLs of the thread pitch diameter within a tolerance zone having a diameter equivalent to 4% of the maximum width across flats.
8 THICKNESS
The nut thickness shall be the overall distance, measured parallel to the axis of the nut, from the top of the nut to the bearing surface of hex nuts, and to the plane of the bearing circle diameter of hex fknge nuts. Raised identification markings, if present, shall be excluded.
9 WRENCHING HEIGHT
The wrenching height is the distance, measured at a corner of the hex, from the bearing surface of hex nuts, and from the junction of the hex portion with the flange of hex flange nuts to the last plane of full formed hex, i.e., the plane perpendicular to the nut axis that is dosest to the top of the nut and at which the width across corners is within its specified limits. Wrenching height for hex nuts is dimension M1 In Table 1, and is subject to measurenwnt, Wrenching height for hex fbnge nuts is dimension T1 in Table 2 and is controlled by the gaging requirenwnt specified in para. 10.
10 GAGING OF HEX PORTION OF
HEX FLANGE NUTS
The nut shall be gaged using two plain ring gages, A and B, to demonstrate the coincidental acceptability of hex height, wrenching height, and width across corners. (See figure above Table 2.) Gage A shall be placed over the hex and shall seat on the flange. Gage B shall be placed on the top of the nut normal to the nut axis. The two gages shall not be in contact.