Expect to see regular hex-head, flanged or washer hex-head ... On the left is an SAE J429 Grade 1 or 2 bolt with no head markings. Center is a Grade 5 bolt with three hash marks.

Points to consider include the following: hex size (the wrench size ... There are no markings on the head of a Grade 2 bolt (more on this later). This grade is usually found in hardware stores ...

The ball end of a hex wrench. This unusual shape allows the tool to enter the screw head and still turn it at ... is that the SAE set can tighten the bolt on the metric set and vice versa, so ...