TM-9-2350-311-20-2
HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5
TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS
DECEMBER 1993
TM-9-2350-311-20-2 - Page 786 of 828
TM 9–2350–311–20–2
F–6
F–5
FASTENER GRADE — CONTINUED
Table F–4 SAE SCREW AND BOLT MARKINGS
SCREWS
BOLTS
SAE grade 2
No markings
SAE grade 6
Four radial dashes
90
°
apart
SAE grade 3
Two radial dashes
180
°
apart
SAE grade 7
Five radial dashes
72
°
apart
SAE grade 5
Three radial dashes
120
°
apart
SAE grade 8
Six radial dashes
60
°
apart
MARKINGS ON HEX LOCKNUTS
Grade A – no marks
Grade A – no marks
Grade A – no notches
Grade B – three marks
Grade B – letter B
Grade B – one notch
Grade C – six marks
Grade C – letter C
Grade C – two notches
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