ISO 286 preferred fits

Hole-basis (H) and shaft-basis (h) fits from ISO 286 and DIN 7157, grouped by type. Not sure which type you need? See types of fits. Looking for a single class instead of a fit? See the tolerance classes.

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.
H7/h7Locational clearanceA hand-assembled sliding/locational fit slightly looser than H7/h6, since both hole and shaft are held to the same IT7 grade: covers, spacers and jig bushings located by other means.
H7/h8Locational clearanceLooser again than H7/h7 for economical sliding and location where cost matters more than precision: sheet-metal brackets, low-duty pins and bushings, prototype fixtures.
H8/h9Locational clearanceWide, low-cost sliding/locating fit on an IT8 hole for parts that just need to go together and stay roughly aligned: guards, covers, non-critical linkage pins.
H8/g7Sliding fitCoarser than H7/g6 for guide pins, sliding sleeves and levers needing smooth, near-zero-play motion but made on general-purpose (not precision) machine tools.
H7/f6Close running fitTighter running clearance than H7/f7 for precision-ground shafts in plain bearings: measuring-instrument spindles, small precision pumps, optical mechanisms.
H7/e7Easy running fitGenerous running clearance for plain bearings on shafts turning at moderate-to-high speed with average lubrication: pump and fan shafts, multi-bearing line shafting.
H7/e8Easy running fitCoarser than H7/e7 for less critical plain bearings where the shaft is only held to IT8: conveyor rollers, agricultural machinery shafts.
H7/d8Loose running fitFree-running clearance for shafts in simple plain bearings subject to dirt, misalignment or thermal growth: material-handling rollers, low-speed gearbox shafts.
H8/d9Loose running fitWide clearance on an IT8/IT9 pair for rough-service shafts and bushings where easy running matters more than alignment or finish: agricultural and construction equipment.
H8/e9Free running fitFree-running plain-bearing fit for shafts made to a coarser IT9 grade, used where H9/e9-class play is acceptable but the housing bore needs the tighter IT8 tolerance.
H9/f8Easy running fitEasy-running clearance for shafts in plain bearings where moderate speed and normal lubrication are expected but full IT7 precision isn't needed: fans, light gearboxes, farm-machinery drivetrains.
H6/f6Precision running fitHigh-precision running clearance for ground shafts in instrument and machine-tool plain bearings where H7/f7-class play is too loose: spindle bearings, precision slides.
H6/h6Precision locational fitTighter than H6/h5's own cousin H7/h6, for gauging and instrument components positioned with almost no play but still assembled and separated by hand.
G6/h5Precision sliding fit (shaft basis)Shaft-basis equivalent of H6/g5, built around a ground reference shaft rather than a reamed hole: gauge blocks, instrument slides, precision jig components.

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.
H7/j6Locational transitionA lighter transition than js6/k6, still seen on older (pre-ISO 286) drawings for ball-bearing inner rings under light, steady load; locates the part but allows hand assembly with only an occasional tap.
H7/n7Locational transitionCoarser than H7/n6 for firm, press-assembled locational fits on an IT7 hole: gear rims on hubs, bushings in cast housings, parts that are rarely dismantled.
H8/p7Locational transitionCoarser than H7/p7, on an IT8 hole; lands as a light interference or a very tight clearance, used where full H7/p6-class precision isn't justified but the joint must not move in service.
H8/js7Locational transitionSymmetric transition fit (equal chance of clearance or interference) on an IT8 hole for lower-cost locational assemblies that still need accurate centring: fixture plates, coarse gear-on-shaft assemblies.
H8/m7Locational transitionTighter than H8/n7, on an IT8 hole; a press-assembled locational fit for parts that must resist vibration but stay removable, where full H7/m6 precision isn't justified.
H8/n7Locational transitionFirm, near-interference transition fit on an IT8 hole; parts are rarely dismantled once pressed together, e.g. bearing bushes and gear hubs in cost-driven designs.
K6/h5Precision transition (shaft basis)Shaft-basis equivalent of H6/k5 — a precision push fit for parts located on a shared ground reference shaft, e.g. several instrument components on one spindle.
M6/h5Precision transition (shaft basis)Shaft-basis equivalent of H6/m5; a light press fit on a precision shaft for parts that must not shift, common where several components share one ground shaft.

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.
H7/p7Locational interferenceCoarser than H7/p6 for interference fits that lock parts against movement and light torque without a key: bushings pressed into castings, locating pins in fixtures.
H7/t6Drive fitHeavier press fit than H7/s6 for permanent shaft-hub joints carrying substantial torque without a key; only defined above 24 mm by ISO 286 — use H7/s6 or H7/u6 below that.
H7/x6Force fitThe heaviest standard shrink/press fit, for permanent, high-torque assemblies; expect to heat the hub or cool the shaft substantially before assembly.
N6/h5Precision interference (shaft basis)Shaft-basis equivalent of H6/n5, for precision parts that must stay fixed on a shared ground shaft without a key.
P6/h5Precision interference (shaft basis)Shaft-basis equivalent of H6/p5; a firm precision press fit for instrument components located on a common ground shaft.