Standards reference
ISO 898-1 — Mechanical Properties of Steel Bolts, Screws and Studs
DraftFit reference page for ISO 898-1 property classes used in preliminary metric bolt calculations.
Reference
ISO 898-1:2013
ISO 898-1:2013 was confirmed in 2025 and remains current while a replacement work item is under development.
What the standard covers
ISO 898-1 specifies mechanical and physical properties for carbon-steel and alloy-steel bolts, screws and studs with defined property classes under its stated scope and test conditions.
What it does not give DraftFit automatically
A bolt property class does not create one universal tightening torque. Joint geometry, friction, lubrication, preload target and tightening method still matter, which is why DraftFit exposes those assumptions separately.
Calculator
Metric Thread & Bolt Calculator →This page is an orientation aid, not a reproduction of the standard. Obtain and use the controlled standard required by your project.