on linear sizes, specifically for cylindrical features (holes and shafts) and parallel surfaces
: The tolerance zone for the shaft . "g" indicates a slight clearance from the zero line. "6" indicates the IT6 tolerance grade.
The letter (for holes) and h (for shafts) are critical anchors because their tolerance zone starts exactly at the nominal size (the lower deviation for H is zero; the upper deviation for h is zero). 3. Types of Fits iso 286 pdf
Note: For official certification or legal manufacturing contracts, always purchase the official ISO 286 PDF from the ISO store or your national standards organization to ensure you have the latest, unaltered data.
Understanding these charts reduces manufacturing defects, ensures global interchangeability of parts, and streamlines production workflows. The letter (for holes) and h (for shafts)
Fundamental deviation (H = Basic Hole, where lower deviation is 0). 7: IT Grade (indicates the magnitude of tolerance). The IT Grades (International Tolerance)
Enables components made in different locations to fit together properly. for the g6 shaft
When a hole and a shaft are assembled, their relationship forms a "fit." ISO 286 categorizes these into three main types: 1. Clearance Fit
Similarly, for the g6 shaft, the table would show the upper deviation es = -12 μm and the lower deviation ei = -34 μm . The finished shaft must therefore be between 51.988 mm and 51.966 mm. This combination creates a specific type of fit—in this case, a clearance fit.
By combining different hole and shaft tolerance classes, engineers create three primary types of fits: