Thread Length: 5/16", Fastener Length: 1-55/64", Thread: 5/16-24, Grip Length: 1-3/8", steel comp e4340 overall or steel comp 4340 overall or steel comp 8740 overall or steel comp 4130 overall or steel comp 6150 overall
From 0.311" and 0.378"
From 1.853" and 1.873"
From 0.157" and 0.172"
Width Between Flats
From 0.492" and 0.502"
From 0.3108" and 0.3117"
Shank Unthreaded Hole Diameter
0.076 inches minimum first hole and 0.086 inches maximum first hole
Nominal Thread Diameter
From 1.375" and 1.391"
Thready Qty Per Inch (tpi)
36.0 rockwell c minimum and 41.0 rockwell c maximum
Distance From Head Largest Bearing Surface To Shank Hole Center
1.738 inches minimum first hole and 1.768 inches maximum first hole
63.0 microinches bearing surface of head
63.0 microinches grip
W/retaining element on shank
Steel comp e4340 or steel comp 4340 or steel comp 8740 or steel comp 4130 or steel comp 6150
Cadmium and chromate
Surface Treatment Spec
Qq-p-416 ty 2 cl 2 fed spec all treatment responses
Thread Series Designator
Bolt, Close Tolerance, also referenced with federal logistics item name code 27851
- An externally threaded fastener whose unthreaded portion is of a specified grip length, plated or unplated, and is machined to a tolerance of one thousandth (0.001) of an inch (0.025 mm) or less of a specific diameter for items one inch (25 mm) or less in diameter. items over one inch (25 mm) in diameter shall have a tolerance of fifteen ten-thousandths (0.0015) of an inch (0.038 mm) or less. the nominal major diameter of the threads shall be at least one thousandth (0.001) of an inch (0.025 mm) below the minimum shank diameter, but not below the minimum major diameter for applicable class of fit, as shown in the screw thread standards, fed std h28 and/or other nationally recognized standards. the head is not designed to be held or driven with an inserted driver, nor is it designed for rotation by the thumb and fingers. a locking feature may be incorporated in the design of the head or threads. for items having close tolerance, and fabricated from material having 160,000 pounds per square inch (1100 megapascals) minimum tensile strength, see bolt, shear. for items fabricated from material having less than 160,000 pounds per square inch (1100 megapascals) minimum tensile strength and not having a close tolerance, see bolt, machine.