Fastener; Fastener Strength Identification - PREVOST H3-41 Maintenance Manual

SECTION 00 : GENERAL INFORMATION

4. FASTENER

4.1 FASTENER STRENGTH IDENTIFICATION

Most commonly used metric fastener strength
property classes are 9.8 and 10.9 with the class
identification embossed on the head of each
bolt. Customary (inch) strength classes range
from grade 2 to 8 with radial line identification
embossed on each bolt head actual grade (i.e., a
grade 7 bolt will have 5 embossed radial lines on
the bolt head). Some metric nuts will be marked
with single digit strength identification numbers
on the nut face. Figure 12 shows the different
strength markings.
FIGURE 11: THREAD NOTATION
FIGURE 12: BOLT STRENGTH MARKINGS
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PA1621 Maintenance Manual All Series | Section 00 revised Sept 2019
When replacing metric fasteners, be careful to
use fasteners of the same or greater strength
than the original fasteners (the same number
marking or higher). It is also important to select
replacement fasteners of the correct size.
Correct replacement fasteners are available
through the parts
fasteners available in after-market parts sources
were designed to metric standards of countries
other than the United States and may be of a
lower strength, may not have the numbered
head marking system, and may be of a different
thread pitch.
division. Some metric
00002
00003