Hex Nut Archives - *ficient design

Hex Nut Grade Identification — Markings, Material & Mechanical Properties

February 24, 2026July 24, 2010 by Mike M.

Matching Nut Grades to Bolt Grades Using the wrong nut with a high-strength bolt is a surprisingly common mistake — and it’s dangerous. A Grade 5 nut on a Grade 8 bolt will strip the nut threads before the bolt reaches its rated clamp load. Always match (or exceed) the nut grade to the bolt … Read more

Hex Nut Dimensions — Width Across Flats & Height (ASME B18.2.2)

February 24, 2026May 24, 2010 by Mike M.

Standard Hex Nut Sizes These are the basic dimensions for standard hex nuts per ASME B18.2.2. The “width across flats” is what you need for wrench/socket sizing. Nominal Size Threads/in (UNC) Width Across Flats (in) Width Across Corners (in) Height (in) 1/4″ 20 7/16 0.505 7/32 5/16″ 18 1/2 0.577 17/64 3/8″ 16 9/16 0.650 … Read more

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