From the above it will be realized
that are a very large number of combinations of hole deviation and
tolerance with shaft deviation and tolerance. However, a given
manufacturing organization will require a number of different types
of fit ranging from tight drive fits to light running fits for
bearing etc. Such a series of fits may be obtained using one of two
ISO standard system:
The
Shaft Basis System
For a given nominal size a series of
fits is arranged for a given nominal size using a standard shaft and
varying the limits on the hole.
The
Hole Basis System
For a given nominal size, the limits
on the hole are kept constant, and a series of fits are obtained by
only varying the limits on the shaft.
The
HOLE SYSTEM is commonly used because holes are more difficult to
produce to given size and are more difficult to inspect. The H series
(lower limit at nominal, 0.00) is typically used and standard tooling
(e.g. H7 reamers) and gauges are common for this standard.
Clearance Fits ISO Standard "Hole Basis"
Transition Fits ISO Standard "Hole Basis"
Interference Fits ISO Standard "Hole Basis"
Comparative Roughness Value
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