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  • Points of screws shall be tapered and fluted or slotted as illustrated above for the respective types. The flute on Type T screws shall have an included angle of 90º to 95º and the thread cutting edge located above the axis of screw. Tapered threads shall have unfinished crests, and the flutes or slots shall extend through the first full thread beyond taper except for Type F screws on which tapered threads may be complete at manufacturer's option and flutes may be one pitch short of the first
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Unit of Measure

Manufacturer

Manufacturer

Industrial Fasteners Institute

Specifications

Product

Tapping Screws

Unit of Measure

English

Nominal Size or Basic Screw Dia.

7/16 in

Nominal Size or Basic Screw Dia. (Decimal)

0.4375 in

Max. Major Dia. (D)

0.4375 in

Min. Major Dia. (D)

0.4281 in

Ref. Point Dia. (P)

0.387 in

Max. Point Taper Length For Short Screws (S)

0.175 in

Min. Point Taper Length For Short Screws (S)

0.125 in

Max. Point Taper Length For Long Screws (S)

0.225 in

Min. Point Taper Length For Long Screws (S)

0.175 in

Determinant Lengths for Point Taper 90º Heads (L)

13/32 in

Determinant Lengths for Point Taper Csk Heads (L)

9/16 in

Min. Practical Nominal Screw Lengths for 90º Heads (L)

3/8 in

Min. Practical Nominal Screw Lengths for Csk Heads (L)

17/32 in

Codes and Standards

Codes and Standards

ASME B18.6.4 1998

Threads Per Inch

Threads Per Inch

20