Applicable to screw types as indicated by code symbols.
  • Types B and BP thread forming and Types BF and BT thread cutting.

This type of recess has a large center opening, wide straight wings, and blunt bottom, with all edges relieved or rounded.
Unit of Measure

Manufacturer

Manufacturer

N/A Industrial Fasteners Institute

Specifications

Product

N/A Tapping Screws

Unit of Measure

N/A English

Type

N/A Type IA

Nominal Size or Basic Screw Dia.

N/A 7/16 in

Nominal Size or Basic Screw Dia. (Decimal)

N/A 0.4375 in
Applicable to Screw Types1 N/A 3

Ref. Recess Dia. (M)

N/A 0.404 in

Ref. Recess Depth (T)

N/A 0.253 in

Ref. Recess Width (N)

N/A 0.086 in

Driver Size

N/A 4

Max. Recess Penetration Gaging Depth

N/A 0.235 in

Min. Recess Penetration Gaging Depth

N/A 0.217 in

Codes and Standards

Codes and Standards

N/A Abstract of ASME B18.6.4 1998
  • 1 1 = Circle, 3 = Triangle, 4 = Square
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