This type of recess has a large center opening, wide straight wings, and blunt bottom, with all edges relieved or rounded.
Applicable to screw types as indicated by code symbols.
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
Specifications
Product |
N/A Tapping Screws |
Unit of Measure |
N/A English |
Type |
N/A Type IA Long Screws with Shoulder |
Nominal Size or Basic Screw Dia. |
N/A 5/16 in |
Nominal Size or Basic Screw Dia. (Decimal) |
N/A 0.3125 in |
Head Size |
N/A 1/4 in |
Applicable to Screw Types1 |
N/A
1 3 4 |
Ref. Recess Dia. (M) |
N/A 0.284 in |
Ref. Recess Depth ((T) |
N/A 0.168 in |
Ref. Recess Width (N) |
N/A 0.057 in |
Driver Size |
N/A 3 |
Max. Recess Penetration Gaging Depth |
N/A 0.155 in |
Min. Recess Penetration Gaging Depth |
N/A 0.137 in |
Max. Protrusion Above Gaging Dia. (F) |
N/A 0.129 in |
Min. Protrusion Above Gaging Dia. (F) |
N/A 0.095 in |
Gaging Dia. (G) |
N/A 0.424 in |
- 1 1 = Circle, 2 = Diamond, 3 = Triangle, 4 = Square