ASME B18-2-4-6M:2010 pdf download

ASME B18-2-4-6M:2010 pdf download.Metric Heavy Hex Nuts
1 SCOPE
(a) This Standard covers the complete general and dimensionaldata for metric heavyhexnuts M12 through M100 recognized as American National Standard. (b) The inclusion ofdimensional data in this Standard is not intended to imply that all of the nut sizes in conjunction with various options described herein are stock items. Purchasers should consult with suppliers concerning lists of stock production heavy hex nuts.
2 COMPARISON WITH ISO STANDARDS
Heavy hex nuts in normal thread diameters M12 through M36 as covered in this Standard have been coordinated to the extent possible with ISO 4775 (see Appendix A for dimensional differences).
6 WIDTH ACROSS FLATS
(a) The width across flats shall be the distance, mea- sured perpendicular to the axis of the nut, between two opposite wrenching flats. (b) The minimum width across flats does not apply for 25% ofthe minimum nut thickness as measured from either face. (c) On nonferrous products where milled-from-bar material is used, the dimensions across flats may be modified to conform to the dimensions of the bar mate- rial when agreed to between the purchaser and the supplier.
7 THICKNESS
The nut thickness shall be the overall distance, mea- sured parallel to the axis of the nut, from the top of the nut to the bearing surface, and include the thickness of the washer face where provided, but exclude raised identification markings, where they are permitted.
8 TOPS AND BEARING SURFACES
(a) Nuts shall be either double chamfered or have a washer faced bearing surface and a chamfered top. (b) The diameter of the bearing surface shall not exceed the width across flats nor be less than the bearing face diameter specified in Table 1. The measurement of the bearing surface diameter shall be taken at 0.1 mm below the bearing surface as shown in Table 1. (c) Within the minimum diameter, D w , the bearing surface shall be flat and perpendicular to the axis of the thread pitch diameter within the total runout limit specified in Table 1. (d) The tops of washer faced nuts shall be flat and the diameter of the chamfer circle shall be equal to the maximum width across flats within a tolerance of −15%. (e) The length of chamfer at hex corners shall be from 5% to 15% of the nominal thread diameter. The surface of the chamfer may be slightly convex or rounded.
11 COUNTERSINK
The tapped hole shall be countersunk on the bearing face(s). The countersink included reference angle shall be 90 deg to 120 deg. The maximum countersink diame- ter shall be 1.08 times the nominal thread diameter; the minimum countersink diameter shall be the nominal thread diameter.
12 THREADS
(a) Threads shall be metric coarse threads with class 6H tolerances in accordance with ASME B1.13M. (b) Nuts intended for use with externally threaded fasteners which are plated or coated with a plating or coating thickness (e.g., hot-dip galvanized) requiring overtapping of the nut thread to permit assembly shall have overtapped threads in conformance with require- ments specified in ASTM A 563M.
17 DESIGNATION
(a) Heavy hex nuts shall be designated by the follow- ing data, preferably in the sequence shown: product name, designation of Standard (ASME B18.2.4.6M), nominal diameter and thread pitch, steel property class or material identification, and protective coating if required. NOTE: It is common practice in ISO Standards to omit thread pitch from the product designation when screw threads are the metric coarse thread series (e.g., M10 is M10 ? 1.5). EXAMPLE: Heavy Hex Nuts, ASME B18.2.4.6M, M10 ? 1.5, ASTM A 563M Class 9, zinc plated per ASTM F 1941M Fe/Zn5C (b) The recommended B18 part identifying number- ing system (PIN) for metric heavy hex nuts is included in ASME B18.24. This system may be used by any user needing a definitive part numbering system.