NAS1581F4R11

Part identification

NSN	5305-01-197-4650
NIIN	01-197-4650
FSC	5305
FSG	53
Item Name	Screw, Close Tolerance
INC	29294
Assigned Date	21-DEC-1984
Status	Active

Technical characteristics

Thread Class	3A
Thread Direction	Right-hand
Thread Length	0.378 inches minimum and 0.428 inches maximum
Fastener Length	1.076 inches minimum and 1.106 inches maximum
Head Style	Flat countersunk
Head Diameter	0.350 inches minimum and 0.3988 inches maximum
Grip Diameter	0.2485 inches minimum and 0.2495 inches maximum
Internal Drive Style	Offset cruciform (torque set)
Nominal Thread Diameter	0.250 inches
Grip Length	0.678 inches minimum and 0.698 inches maximum
Thread Quantity per Inch	28
Minimum Tensile Strength	160000 pounds per square inch
Hardness Rating	36.0 rockwell C minimum overall and 40.0 rockwell C maximum overall
Countersink Angle	99.0 degrees minimum and 101.0 degrees maximum
Surface Finish	32.0 microinches grip
Surface Finish	32.0 microinches threads
Special Features	Internal drive ribbed
Material	Steel comp 4140 overall or steel comp E4340 overall or steel comp 8740 overall
Material Document and Classification	MIL-S-5626 mil spec 1ST material response overall or MIL-S-5000 mil spec 2ND material response overall or MIL-S-6049 mil spec 3RD material response overall
Surface Treatment	Cadmium overall and chromate overall
Surface Treatment Document and Classification	QQ-P-416, type 2, class 2 fed spec single treatment response overall
Thread Series Designator	UNJF
Specification/Standard Data	80205-NAS1581 professional/industrial association standard

Manufacturers

National Aerospace Standards (CAGE 80205) — Type C

National Aerospace Standards (CAGE 80205) — Type C

Alternate part numbers

NAS1581A4R11 (CAGE 80205)

NAS1581F4R11 (CAGE 80205)