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Maryland Metrics: Technical Data. The bolt head are also marked with a manufacturers mark (e.g., MFG in the figure). Metric bolts are identified by their nominal diameter and the pitch. A 24-mm diameter bolt with a 3-mm pitch is designated as an M24x3 bolt, the M indicating that this is a metric bolt.
Grade 8 Medium Carbon Alloy Steel, Quenched and Tempered 1/4 thru 1-1/2 120,000 130,000 150,000 1/4 thru 5/8 80,000 – 90,000 100,000 – 125,000 3/4 thru 1 100,000 Stainless markings vary. Tensile Strength: The maximum load in tension (pulling apart) which a material can withstand before breaking or fracturing.