• Surface Condition. Bolts need not be finished on any surface except threads.
  • Top of Head. Top of head shall be full form and chamfered with the diameter of chamfer circle being equal to the maximum width across flats, within a tolerance of minus 15 percent.
  • Head Taper. Maximum width across flats and across corners shall not be exceeded. No transverse section through the head between 25 percent and 75 percent of actual head height, as measured from the bearing surface, shall be less than the minimum width across flats and across corners.
  • Bearing Surface. A die seam across the bearing surface is permissible. Bearing surface shall be perpendicular to the axis of the body within a tolerance of 3 deg for 1.
Unit of Measure

Manufacturer

Manufacturer

N/A Industrial Fasteners Institute

Specifications

Product

N/A Square and Hex Bolts and Screws

Unit of Measure

N/A English

Nominal Size or Basic Product Diameter

N/A 1/4 in

Nominal Size or Basic Product Diameter (Decimal)

N/A 0.2500 in

Max. Full-Size Body Diameter (E)

N/A 0.260 in

Min. Full-Size Body Diameter (E)

N/A 0.237 in

Basic Width Across Flats (F)

N/A 7/16 in

Max. Width Across Flats (F)

N/A 0.438 in

Min. Width Across Flats (F)

N/A 0.425 in

Max. Width Across Corners (G)

N/A 0.505 in

Min. Width Across Corners (G)

N/A 0.484 in

Basic Head Height (H)

N/A 11/64 in

Max. Head Height (H)

N/A 0.188 in

Min. Head Height (H)

N/A 0.150 in

Max. Radius of Fillet (R)

N/A 0.03 in

Min. Radius of Fillet (R)

N/A 0.010 in

Codes and Standards

Codes and Standards

N/A ASME B18.2.1 1996

Thread Length for Bolt Lengths

Nom. LT for Bolt Length (6 in. and Shorter)

N/A 0.750 in

Nom. LT for Bolt Length (Over 6 in.)

N/A 1.000 in
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