Shafts and Axles

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Relevant Standards
BS EN 20286-1:1993(ISO 286-1:1988 )...... ISO system of limits and fits. Bases of tolerances, deviations and fits BS EN 20286-2 : 1993(ISO 286-2:1988 ).... ISO system of limits and fits. Tables of standard tolerance grades and limit deviations for holes and shafts

Notes: The tolerance of size is normally defined as the difference between the upper and lower dimensions.

The need for tolerances to be identified on drawings is vital to allow assembly of parts in the desired way and interchangeability of parts as required in modern manufacturing methods.

ISO 286 implements 20 grades of accuracy to satisfy the requirements of different industries.


 * IT01,  IT0,   IT1,   IT2,   IT3,   IT4,  IT5,  IT6.. Production of gauges and instruments.
 * IT 5,  IT6,   IT7,  IT8,  IT9,  IT10,  IT11,  IT12...Precision and general Industry.
 * IT11,  IT14,   IT15,   IT16..Semi finished products
 * IT16,  IT17,  IT18 ..Structural Engineering

Hole and Shaft tolerance tables- Using Fundamental Deviations and Tolerance Band T

 * ISO Tolerance Band T (3-315mm size)
 * ISO Tolerance Band T (315-3150mm size)


 * ISO Shaft limit nearest Zero (3-500mm shaft size)
 * ISO Shaft limit nearest Zero (500-3150mm shaft size)


 * ISO Hole Nearest limit nearest Zero (0-500mm hole size)
 * ISO Hole Nearest limit nearest Zero (500-3150mm hole size)

Examples in using above tables..

Note: The tolerance band T is an absolute length value it does not have a negative value.

Hole Dia 110mm H11,... Nearest zero ( El )= 110mm + 0mm = 110,000mm ... Furthest from zero ( ES )= 110mm + (0+ T=0,220)=110,220mm Resulting limits 110,000/110,220

Shaft 110mm e9... Nearest zero ( es ) = 110mm - 0,072=109,928mm... Furthest from zero ( ei ) = 110mm - (0,072 + T=0,087) = 109,841mm Resulting limits 109,928/109,841

Note for the tolerance bands which can be either side of zero, (J,K,N,j ) The diagrams provided with the table clearly show calculation needed.e.g. consider Hole 300K7.

T= 52 micrometres (0,052mm). Limit nearest zero ( K ) ES = 16 micrometres = (0,016mm) Limit furthest from zero ( K ) El = (0,016- 0,052)= -0,036 Limits therefore (300 -0,036) = 299,964..and ...300+0,016= 300,016 limits 299,964/300,016

Hole and Shaft Tolerances to ISO 286-2

 * ISO Hole Limits (3-400mm Hole Size)
 * ISO Hole Limits (400-3150mm Hole Size)
 * ISO Shaft Tolerance(3-400mm Hole Size)
 * ISO Shaft Tolerance(400-3150 mm Hole Size)

Example limits and fits using hole basis

Machining Process associated with ISO IT Tolerance Grade..