1 Amount of force required to pull apart fastener

2 Converted from megapascals (MPa) PSI/145 = MPa or MPa x 145 = PSI

Inch

• Grade indicates strength level in the inch system.
• When specifying inch fastener strengths, call them out as grades.

Metric

• Property class indicates strength level in the metric system.
• When specifying metric fastener strengths, call them out as property classes. Don't confusingly ask for a metric Grade 8 hex cap screw. Ask for a metric property class 10.9 instead.

Warning: Similar numbers used for grade and property class designations don't stand for the same strength. For example, a Grade 8 hex cap screw and a property class 8.8 hex cap screw have different tensile strengths. See table.