• 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%.
  • Wrenching Height, J. Wrenching height is a distance measured from the bearing surface up the side of the head at the corners. The width across corners shall be within the specified limits for minimum wrenching height.
  • Bearing Surface. Bearing surface shall be flat and washer faced. Diameter of washer face shall be equal to
  • more
Unit of Measure

Manufacturer

Manufacturer

Industrial Fasteners Institute

Specifications

Product

Square and Hex Bolts and Screws

Unit of Measure

English

Nominal Size or Basic Product Diameter

2-3/4 in

Nominal Size or Basic Product Diameter (Decimal)

2.7500 in

Max. Body Diameter (E)

2.7500 in

Min. Body Diameter (E)

2.711 in

Basic Width Across Flats (F)

4-1/4 in

Max. Width Across Flats (F)

4.250 in

Min. Width Across Flats (F)

4.112 in

Max. Width Across Corners (G)

4.907 in

Min. Width Across Corners (G)

4.688 in

Basic Head Height (H)

1-11/16 in

Max. Head Height (H)

1.744 in

Min. Head Height (H)

1.632 in

Min. Wrenching Height (J)

1.151 in

Max. Transition Thread Length (Y)

1.250 in

Max. Circular Runout of Bearing Surface FIM

0.074 in

Codes and Standards

Codes and Standards

ASME B18.2.1 1996

Thread Length for Screw Lengths

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

6.000 in
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