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ISO 286 Fits & Tolerance Reference

Preferred hole-basis fits (H7/g6, H7/h6, H7/p6, H7/u6, …) with tolerance bands and fit type.

Digital Machine

Fit zones at a glance — drawn to scale

Drawn-to-scale ISO 286 hole-basis tolerance zones for the 6 to 10 millimeter band. Clearance: the g6 or h6 shaft zone sits at or below the H7 hole zone, so the fit is never a press. Transition: the k6 or n6 shaft zone overlaps the hole zone, so the result can be a gap or a press. Interference: the p6 or s6 shaft zone sits at or above the hole zone, so assembly is always a press.ISO 286 TOLERANCE ZONES — DEVIATIONS IN µm (0.001 mm), over 6 through 10 mm NOMINAL BAND — DRAWN TO SCALEH7+150g6−5−14h60−9GAPCLEARANCEShaft zone at / below the hole zone — never a press.H7/g6 gap 5–29 µm · H7/h6 gap 0–24 µmH7k6+10+1n6+19+10GAP OR PRESSTRANSITIONShaft zone overlaps the hole zone — gap or press.H7/k6 light tap · H7/n6 mallet — either outcomeH7p6+24+15s6+32+23PRESSINTERFERENCEShaft zone at / above the hole zone — never a gap.H7/p6 press 0–24 µm · H7/s6 press 8–32 µm+−ZERO LINE — BASIC SIZEHOLE-BASIS — THE HOLE TOLERANCE IS FIXED (H7 SHOWN); THE SHAFT LETTER SETS THE FIT

Preferred hole-basis fits

FitISOTypeTypical use
Loose runningH11/c11ClearanceLinkages, lever pivots, hinge pins
Free runningH9/d9ClearanceBushings on shafts, low-precision bearings
Close runningH8/f7ClearanceSpindle bearings, pilot pins, gear shafts
SlidingH7/g6ClearanceSliding gears, drill bushings, sliding shafts
Locational clearanceH7/h6ClearanceLocating shafts, dowel-pin sleeves, alignment fits
Locational transition (push)H7/k6TransitionPress-fit dowel pins (small), removable sleeves
Locational transition (heavy push)H7/n6TransitionLocating bushings, fixed dowel pins
Locational interference (light press)H7/p6InterferenceBearing inner rings, fixed bushings
Medium driveH7/s6InterferenceCoupling on shafts, heavy bushings
Force fitH7/u6InterferencePermanent gear/wheel-on-shaft, heavy press-fits

■ Clearance = gap ·■ Transition = either ·■ Interference = press

Tolerance bands — over 6 through 10 mm nominal

ClassUpper (mm)Lower (mm)Role
Holes — lower limit at zero
H11+0.0900Hole — loose
H9+0.0360Hole — free running
H8+0.0220Hole — close running
H7+0.0150Hole — standard precision
Shafts — clearance (at / below zero)
h60−0.009Shaft — locational clearance
g6−0.005−0.014Shaft — sliding
f7−0.013−0.028Shaft — close running
d9−0.040−0.076Shaft — free running
c11−0.080−0.170Shaft — loose running
Shafts — transition (overlap the H7 zone)
k6+0.010+0.001Shaft — push fit (transition)
n6+0.019+0.010Shaft — heavy push (transition)
Shafts — interference (at / above H7 max)
p6+0.024+0.015Shaft — light press (interference)
s6+0.032+0.023Shaft — medium drive (interference)
u6+0.037+0.028Shaft — force fit (interference)

Values in mm · + above / − below the zero line · CAPITAL = hole · lowercase = shaft

Selection rules of thumb

  • Default H7/h6 for accurate location (~80% of cases): locating sleeves, alignment & dowel-pin holes.
  • Sliding motion: drop the shaft to g6 (H7/g6) or f7 (H8/f7). Don’t use h6 for sliding parts — it binds under thermal growth.
  • Press fits: start light (H7/p6), then medium (H7/s6), then heavy (H7/u6). Beyond u6 usually needs shrink-fit.
  • k6 / n6 are transition: sometimes clearance, sometimes interference — use only when the ambiguity is intentional.
  • Size matters: a 10 mm H7 hole is +0.015; a 100 mm H7 hole is +0.035. Look up the actual band — don’t scale linearly.

Hole-basis: the hole tolerance is fixed (typ. H7/H8) and the shaft changes to set the fit. Reading example — a 10 mmH7 hole (+0.015/0) with an h6 shaft (0/−0.009) givesH7/h6: 0 to 0.024 mm clearance. The same H7 hole with p6(+0.024/+0.015) gives H7/p6: 0 to 0.024 mm interference. For the interactive limits & fits visualizer, see the full standard fits guide.

Free engineering reference from Digital Machine
digitalmachine.com · 805-697-7829 · Located in California
Tolerance values are the over 6 through 10 mm nominal band per ISO 286 — look up your actual size band for design-critical work. · September 2026
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