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The deviation that defines the position of the tolerance zone relative to the basic size (indicated by a letter).
The ISO 286 standard is available in PDF format from various sources, including:
Coarse grades used for rough manufacturing processes like casting, forging, or stamping. iso 286 pdf
The shaft is always smaller than the hole, ensuring there is always space (clearance) between them. This allows the parts to move or rotate freely relative to each other. Common application: Journal bearings, sliding pulleys. Example combination: H7/g6. Interference Fit (Press Fit)
The tolerance zones overlap. Depending on the actual manufactured sizes of the individual parts, the assembly could result in either a slight clearance or a slight interference.
– This part contains the actual numerical data tables used by machinists and engineers to look up specific tolerance values based on size ranges. Core Concepts Found in the ISO 286 PDF An authorized distributor for international standards in the
When a hole and a shaft are assembled, their relationship forms a "fit." ISO 286 categorizes these into three main types: 1. Clearance Fit
The algebraic difference between a size and the nominal size.
It applies to cylindrical features (holes and shafts) and two parallel opposite surfaces. The shaft is always smaller than the hole,
The size at which the part contains the maximum amount of material (e.g., the largest shaft or the smallest hole).
An ISO 286 tolerance callout on a blueprint combines these elements into a highly condensed, alphanumeric code:
The theoretical size from which limits are derived.