FF-B-588 Military Specifications Fasteners

Mil Spec FF-B-588 covers toggle bolts and screw expansion sleeves.

Type I – Spring-wing toggle bolts, with two-piece wings

• Class A – Sheet metal wings
  • Style 1 – Machine screw
  • Style 2 – Continuous thread stud
  • Style 3 – Eyebolt
• Class B – Wing wings
  • Style 1 – Machine screw
  • Style 2 – Continuous thread stud

Type II - Tumble-wing toggle bolts, with one-piece sheet metal wings

• Class A - Pivoted bolts
  • Style 1 – Machine screw
  • Style 2 – Continuous thread stud
  • Style 3 – Eyebolt