Applicable to screw types as indicated by code symbols.
  • Type AB thread forming.
  • Types B and BP thread forming and Types BF and BT thread cutting.
  • Type C thread forming and Types D, F, G, and T thread cutting.
Unit of Measure

Manufacturer

Manufacturer

Industrial Fasteners Institute

Specifications

Product

Tapping Screws

Unit of Measure

English

Nominal Size or Basic Screw Dia.

5/16 in

Nominal Size or Basic Screw Dia. (Decimal)

0.3125 in

Head Size

1/4 in
Applicable to Screw Types1 1
3
4

Min. Shoulder Dia. for Other Types (E)

0.302 in

Max. Head Dia. (A)

0.477 in

Min. Head Dia. (A)

0.442 in

Ref. Head Height (H)

0.116 in

Max. Protrusion Above Gaging Dia. (F)

0.050 in

Min. Protrusion Above Gaging Dia. (F)

0.029 in

Gaging Dia. (G)

0.424 in

Codes and Standards

Codes and Standards

Abstract of ASME B18.6.4 1998
  • 1 1 = Circle, 2 = Diamond, 3 = Triangle, 4 = Square
Use trailing wildcard (*) for broader results.