If you find a PDF dated 1983 or 1994, discard it. Those revisions are obsolete and do not reflect modern manufacturing capabilities.
: Highest precision, typically used for critical applications requiring tight fits. Grade B : Medium precision.
If you work with screws, bolts, and nuts, you’ve likely encountered fitment issues—heads that sit too high, threads that bind, or washers that don’t align. is the key international standard that solves these problems by defining precise tolerances for fastener dimensions. iso 4759 pdf
Disclaimer: This article is for informational purposes only. Always refer to the official ISO document for legal and technical compliance. Prices and edition dates are subject to change by ISO.
ISO 4759-1 defines three product grades, which correlate to the fastener’s quality and tolerance tightness: If you find a PDF dated 1983 or 1994, discard it
For engineers and quality inspectors, this standard is the "rulebook" for determining if a fastener is "good" or "bad." It provides the mathematical boundaries that prevent assembly failures and ensure parts from different suppliers are interchangeable.
: For metric threads, tolerances are derived from ISO 965-3 (e.g., 6g for bolts and 6H for nuts in Grade A/B). Grade B : Medium precision
This is the most commonly referenced section for general-purpose fasteners. It applies to bolts, screws, studs, and nuts made of carbon steel or alloy steel. It defines three product grades: