|Table of Contents |Section Contents|
(By permission from Vallory H. Laughner and Augustus D. Hargan, "Handbook of Fastening and Joining of Metal Parts," McGraw-Hill Company, New York, 1956.)
NOTES: All dimensions are in inches. "Finished" in the title refers to the quality of manufacture and the closeness of tolerance and does not indicate that surfaces are completely machined. Taper of the sides of nuts (angle between one side and axis) shall not exceed 2 degrees, the specified width across flats being the largest dimension. Tops of nuts shall be flat and chamfered. Diameter of top circle shall be maximum width across flats within a tolerance of minus 15 percent for washer-faced nuts and within a tolerance of minus 5 percent for double-chamfered nuts. Bearing surface shall be washer-faced or with chamfered corners. Diameter of circle of bearing surface shall be the maximum width across flats within a tolerance of minus 5 percent. Tapped hole shall be counter-sunk 1/64 in over the major diameter of thread for nuts up to and including 1/2 in and 1/32 in over the major diameter of thread for nuts over 1/2 inch in size. Bearing surface shall be at right angles to axis of the threaded hole within a tolerance of 2 degrees for 5/8 in nuts or smaller and 1 degree for nuts larger than 5/8 in; therefore the maximum total runout of bearing face would equal the tangent of specified angle times the distance across the flats. Thread shall be coarse, fine, or 8-thread series, class 2B. Suitable material for steel nuts is covered by ASTM A-307; other materials will be as agreed upon by manufacturer and user. Tolerance on width across flats may be increased 0.015 in for hot-formed nuts 5/8 in and smaller.
Nominal Width across size or Width across flats corners Thickness, nuts Thickness, jam nuts basic major F G H H diameter --------------------- ------------ ------------------- ------------------- of thread Max (basic) Min Max Min Nom Max Min Nom Max Min ------------- ------- ------- ----- ----- ----- ------- ----- ----- ------- ----- ----- # 1/4 0.2500 7/16 0.4375 0.428 0.505 0.488 7/32 0.226 0.212 5/32 0.163 0.150 # 5/16 0.3125 1/2 0.5000 0.489 0.577 0.557 17/64 0.273 0.258 1/16 0.195 0.180 # 3/8 0.3750 9/16 0.5625 0.551 0.650 0.628 21/64 0.337 0.320 7/32 0.227 0.210 # 7/16 0.4375 11/16 0.6875 0.675 0.794 0.768 3/8 0.385 0.365 1/4 0.260 0.240 # 1/2 0.5000 3/4 0.7500 0.736 0.866 0.840 7/16 0.448 0.427 5/16 0.323 0.302 # 9/16 0.5625 7/8 0.8750 0.861 1.010 0.982 31/64 0.496 0.473 11/32 0.365 0.323 # 5/8 0.6250 15/16 0.9375 0.922 1.083 1.051 35/64 0.559 0.535 3/8 0.387 0.363 # 3/4 0.7500 1-1/8 1.1250 1.088 1.299 1.240 41/64 0.665 0.617 27/64 0.446 0.398 # 7/8 0.8750 1-5/16 1.3125 1.269 1.516 1.447 3/4 0.776 0.724 31/64 0.510 0.458 # 1 1.0000 1-1/2 1.5000 1.450 1.732 1.653 55/64 0.887 0.831 35/64 0.575 0.519 1-1/8 1.1250 1-11/16 1.6875 1.631 1.949 1.859 31/32 0.999 0.939 39/64 0.639 0.579 1-1/4 1.2500 1-7/8 1.8750 1.812 2.165 2.066 1-1/16 1.094 1.030 23/32 0.751 0.687 1-3/8 1.3750 2-1/16 2.0625 1.994 2.382 2.273 1-11/64 1.206 1.138 25/32 0.815 0.747 1-1/2 1.5000 2-1/4 2.2500 2.175 2.598 2.480 1-9/32 1.317 1.245 27/32 0.880 0.808 1-5/8 1.6250 2-7/16 2.4375 2.356 2.815 2.686 1-25/64 1.429 1.353 29/32 0.944 0.868 1-3/4 1.7500 2-5/8 2.6250 2.538 3.031 2.893 1-1/2 1.540 1.460 31/32 1.009 0.929 1-7/8 1.8750 2-13/16 2.8125 2.719 3.248 3.100 1-39/64 1.651 1.567 1-1/32 1.073 0.989 2 2.0000 3 3.0000 2.900 3.464 3.306 1-23/32 1.763 1.675 1-3/32 1.138 1.050 2-1/4 2.2500 3-3/8 3.3750 3.262 3.897 3.719 1-59/64 1.970 1.874 1-13/64 1.251 1.155 2-1/2 2.5000 3-3/4 3.7500 3.625 4.330 4.133 2-9/64 2.193 2.089 1-29/64 1.505 1.401 2-3/4 2.7500 4-1/8 4.1250 3.988 4.763 4.546 2-23/64 2.415 2.303 1-37/64 1.634 1.522 3 3.0000 4-1/2 4.5000 4.350 5.196 4.959 2-37/64 2.638 2.518 1-45/64 1.643 1.643 ------------- ------- ------- ----- ----- ----- ------- ----- ----- ------- ----- ----- # Products unified dimensionally with British and Canadian standards.