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 785 of 828

TM 9–2350–311–20–2

Change 2

F–5

Thread patterns are designed as follows:

NOTE

Unless followed with –LH (e.g., 3/4–1 OUNC–2A–LH), threads are right-handed.

Nominal size

No. Threads/in.

Thread symbol

Thread class

3/4

10

UNC

2A

NOMINAL

DIAMETER

GRIP

LENGTH

HEIGHT

OF NUT

BODY

LENGTH

THREAD

LENGTH

THREAD

RUNOUT

LENGTH

THICKNESS

OR HEIGHT

OF HEAD

LENGTH

(BOLT SHAFT)

F–5

FASTENER GRADE

In addition to being classified by thread type, threaded fasteners are also classified by material. The most familiar fastener

classification system is the SAE grading system (Table F–4).