TM-9-2330-335-14-P
SEMITRAILER, TACTICAL, BREAKBULK/CONTAINER TRANSPORTER, 22-1/2 TON, RESET M871R, M871A1R AND M871A2R
TECHNICAL MANUAL; FIELD AND SUSTAINMENT MAINTENANCE MANUAL (INCLUDES REPAIR PARTS AND SPECIAL TOOLS LIST)
SEPTEMBER 2008
TM-9-2330-335-14-P - Page 517 of 640
0088-1
TM 9-2330-335-14&P
0088
FIELD AND SUSTAINMENT MAINTENANCE
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FASTENER SIZE AND THREAD PATTERN
FASTENER SIZE AND THREAD PATTERN
00088
Threaded fasteners are categorized according to diameter of the fastener shank. Thread styles are divided into broad groups,
the two most common being coarse (Unified Course-UNC) and fine (Unified Fine-UNF). These groups are defined by the
number of threads per inch in the bolt shanks. In addition, threads are categorized by thread class, which is a measure of the
degree between threads of the bolt or screws (external threads) and threads of attaching nut or tapped hole (internal threads of
attaching nut or tapped hole) (internal threads). The most common thread class for bolts and screws is Class 2.
Figure 1.
Fastener Size.
088
THREAD CLASSES AND DESCRIPTION
1A
1B
Loose Fit
2A
2B
Medium Fit
3A
3B
Close Fit
447-0242
2
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