General
STRENGTH IDENTIFICATION
CAUTION
When fasteners must be replaced, the new
fasteners must be of the same strength or greater
than the original fasteners. The new fasteners
must also be the correct size.
NOTE: Identification marks are according to bolt
strength. The higher the number or the increase in the
number of marks indicates increased bolt strength.
2
Figure 1. Thread Design
The most common property classes for metric
fasteners are 8.8 and 10.9. The property class is
marked with a number on the head of the capscrew or
on a nut. Property classes less than 8.8 are often not
marked. Grades for inch bolts go from 2 to 8. Grade 2
fasteners normally do not have any marks. The
following tables show the marks that identify the
grades and property classes for different fasteners.
8000 YRM 0231