Aeronautical Standard Machine Bolt
- Hexagon, undrilled Head
- No Cotter Pin Hole
- Fine Threads
- UNF-3A
- Material: Steel
- Finish: Cadmium and chromate
- Major Diameter: 0.25 in.
- Thread Per Inch (TPI): 28
- Grip Length: 1.188 in.
- Industry Standard Specification: AIA/NAS NASM3-20