Item # CRUFCHTSIA03125XXX, Type IA Cross Recessed Undercut Flat Countersunk Head Tapping Screw, 0.3125" Nominal Dia. On Sales Systems Ltd.

When specifying nominal size in decimals, zeros preceding decimal and in the fourth decimal place shall be omitted.
Head dimensions not shown are the same as those of slotted heads.
Not practical to gage sizes No. 0 and No. 1.

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 | Specifications | Codes and Standards

N/A Industrial Fasteners Institute

Product	N/A Tapping Screws
Unit of Measure	N/A English
Type	N/A Type IA
Nominal Size or Basic Screw Dia.	N/A 5/16 in
Nominal Size or Basic Screw Dia. (Decimal)	N/A 0.3125 in
Ref. Recess Dia. (M)	N/A 0.310 in
Ref. Recess Depth (T)	N/A 0.163 in
Ref. Recess Width (N)	N/A 0.085 in
Driver Size	N/A 4
Max. Recess Penetration Gaging Depth	N/A 0.145 in
Min. Recess Penetration Gaging Depth	N/A 0.127 in

N/A Abstract of ASME B18.6.4 1998

Manufacturer