TM 9-2330-275-14&P
H-6. FASTENER GRADE.
In addition to being classified by thread type, thread fasteners are also classified by material. The most familiar
fastener classification system is the SAE grading system (Table H-5).
Markings on Hex Locknuts
GRADE A -No Marks
GRADE A -No Mark
GRADE B -3 Marks
GRADE B - Letter B
GRADE C-6 Marks
GRADE C- Letter C
GRADE A-No Notches
GRADE B - One Notch
GRADE C - Two Notches
H-5/(H-6 Blank)
