FF-S-107 Military Specifications Fasteners

Mil spec FF-S-107 covers tooth lock washers for use in assemblies with bolts, studs, and machine screws.

Type I – Internal tooth flat

• Grade A – Regular
• Grade B – Heavy-duty

Type II – External tooth flat

Type III – Internal-external tooth flat

Type IV – External tooth countersunk (80° - 82°)

Type V – External tooth countersunk (99° - 101°)

• Style 1 – Twisted teeth
• Style 2 – Teeth with up-and-down bent edges