Standards reference
ISO 3601 — O-Rings and Housing Dimensions
DraftFit reference page for the ISO 3601 series used around O-ring dimensions, quality and housing design.
Reference
ISO 3601 series; ISO 3601-2:2025 for housing dimensions
ISO 3601-2:2025 is the current published housing-dimensions edition for general applications.
What Part 2 addresses
ISO 3601-2:2025 specifies housing dimensions for general O-ring applications and addresses both O-ring-first and fixed-hardware design approaches. It covers general hydraulic and pneumatic applications with and without backup rings.
DraftFit scope
DraftFit uses the ISO 3601 series as an engineering reference while also exposing simplified squeeze, fill, stretch/compression and extrusion-gap checks. The calculator documentation identifies where a result is preliminary rather than a complete reproduction of standard tables.
Calculator
O-Ring Groove Calculator →This page is an orientation aid, not a reproduction of the standard. Obtain and use the controlled standard required by your project.