- Thread Class
- 3A
- Thread Direction
- Right-hand
- Thread Length
- 0.354 inches minimum and 0.531 inches maximum
- Fastener Length
- 0.531 inches minimum and 0.562 inches maximum
- Head Style
- Flat countersunk
- Head Diameter
- 0.491 inches minimum and 0.507 inches maximum
- Locking Feature
- Strip threads
- Internal Drive Style
- Cross recess type 1
- End Item Identification
- W/s: helicopter, MH-53E; helcopter, CH-53A/D/E
- Nominal Thread Diameter
- 0.250 inches
- Thread Quantity per Inch
- 28
- Minimum Tensile Strength
- 160000 pounds per square inch
- Countersink Angle
- 99.0 degrees minimum and 101.0 degrees maximum
- Surface Finish
- 32.0 microinches grip
- Surface Finish
- 32.0 microinches threads
- Material
- Iron alloy 660 overall
- Material Document and Classification
- AMS7478 assn std single material response overall
- Surface Treatment
- Passivate overall
- Surface Treatment Document and Classification
- QQ-P-35 fed spec single treatment response overall
- Thread Series Designator
- UNJF
- Specification/Standard Data
- 80205-NAS1189 professional/industrial association standard
Catalogue data is compiled from public DLA/FLIS sources and is provided for
identification. Availability, condition and certification are confirmed on
quotation. OmniSynk Distribution Services is a stocking distributor.