ISO 286 preferred fits

Hole-basis (H) and shaft-basis (h) fits from ISO 286 and DIN 7157, grouped by type.

Clearance fits

H11/c11Loose running fitLarge clearance for parts that must assemble easily despite dirt, heat or poor alignment: agricultural machinery, brake linkages, loose pulleys.
H11/a11Very loose fitMaximum clearance in the standard series; used where parts run hot or where accuracy is irrelevant.
H11/d11Loose running fitFree-running parts with generous clearance, e.g. loose bushes and idler wheels on rough shafts.
H11/h11Loose locational fitParts that must be located but need no precision: spacers, washers, covers on rough shafts.
H9/d9Free running fitShafts running in plain bearings with wide temperature variation, high speed or heavy journal pressure.
H9/e9Free running fitPlain bearings with ample lubrication, multi-bearing shafts, long bushes.
H9/h9Locational clearanceParts that assemble freely and are located by other means; general non-precision positioning.
H8/e8Easy running fitPlain bearings in gearboxes and pumps, sliding gears, easily assembled couplings.
H8/f7Close running fitAccurate machines and shafts in plain bearings at moderate speeds and pressures: machine tool spindles, gearbox shafts.
H8/h7Locational clearanceParts that slide or can be assembled by hand and are located by other means; slightly looser than H7/h6.
H8/h8Locational clearanceGeneral-purpose sliding and locating fit for parts that need to move freely but stay aligned.
H7/f7Close running fitSliding parts and journals at moderate speeds with noticeable but small play.
H7/g6Close running / sliding fitPrecision sliding parts that must move without perceptible play: spindles, sliding gears, guide pins, plungers.
H7/h6Locational clearancePrecisely located parts that can still be assembled and turned by hand: gears on shafts fixed by keys, pulleys, centring flanges.
H6/g5Precision sliding fitHigh-precision sliding parts with minimum play: measuring instrument spindles, precision guide pins.
H6/h5Precision locational fitPrecision parts located by the fit alone and assembled by hand, e.g. gauges and instrument components.
C11/h11Loose running fit (shaft basis)Shaft-basis equivalent of H11/c11 for plain drawn shafting.
A11/h11Very loose fit (shaft basis)Shaft-basis equivalent of H11/a11.
D9/h9Free running fit (shaft basis)Shaft-basis equivalent of H9/d9, used when several parts with different fits sit on one plain shaft.
E9/h9Free running fit (shaft basis)Shaft-basis equivalent of H9/e9.
D10/h9Loose running fit (shaft basis)Generous clearance on a plain shaft for loose pulleys and idlers.
F8/h7Close running fit (shaft basis)Shaft-basis equivalent of H8/f7 for bearings on a plain shaft.
F7/h6Close running fit (shaft basis)Shaft-basis equivalent of H7/f7.
G7/h6Sliding fit (shaft basis)Shaft-basis equivalent of H7/g6 for sliding parts on a ground plain shaft.

Transition fits

H7/js6Locational transitionParts that need accurate location and easy assembly with a light hammer: pulleys, hand-wheels, couplings.
H7/k6Locational transitionThe standard "push fit" for gears, pulleys and ball-bearing inner rings on shafts; assembles with a light press or mallet, transmits torque only with a key.
H7/m6Locational transitionTighter than k6; parts that must not move under vibration but are still removable: bearing bushes, gears, couplings.
H7/n6Locational transitionFirm fit assembled with a press; parts rarely dismantled, e.g. gear rims on hubs, bushes in housings.
H6/js5Precision transitionPrecision parts needing accurate location with easy assembly.
H6/k5Precision transitionPrecision push fit, e.g. ball-bearing inner rings in instruments.
H6/m5Precision transitionPrecision fit resisting movement, assembled with a light press.
H8/k7Transition fitCoarser transition for general machinery where H7/k6 is unnecessarily accurate.
JS7/h6Locational transition (shaft basis)Shaft-basis equivalent of H7/js6.
K7/h6Locational transition (shaft basis)Shaft-basis equivalent of H7/k6, e.g. ball-bearing outer rings in housings.
M7/h6Locational transition (shaft basis)Shaft-basis equivalent of H7/m6.
N7/h6Locational transition (shaft basis)Shaft-basis equivalent of H7/n6; common for bearing outer rings under rotating outer-ring load.

Interference fits

H7/p6Locational interferenceParts that must stay fixed without transmitting large torque: bushes pressed into housings, dowels, gears on shafts with a key.
H7/r6Medium drive fitPress fit transmitting moderate torque; can be dismantled with a press, e.g. bushes, gear rims, shaft collars.
H7/s6Medium drive fitPermanent press fit for steel parts transmitting torque without keys: gear rims, bearing bushes, shaft-hub connections.
H7/u6Force fitHeavy press or shrink fit for permanent assemblies under high load; requires heating the hub or cooling the shaft.
H6/n5Precision interferenceLight press fit for precision parts that must not move.
H6/p5Precision interferencePrecision locational press fit, e.g. bushes in instrument housings.
H8/s7Drive fitCoarser permanent press fit for general machinery.
H8/u7Force fitCoarser heavy press or shrink fit for permanent assemblies.
P7/h6Locational interference (shaft basis)Shaft-basis equivalent of H7/p6.
R7/h6Medium drive fit (shaft basis)Shaft-basis equivalent of H7/r6.
S7/h6Medium drive fit (shaft basis)Shaft-basis equivalent of H7/s6.
U7/h6Force fit (shaft basis)Shaft-basis equivalent of H7/u6.