ISO 286 · interference fit · hole basis
H7/r6 Interference Fit — Hole and Shaft Limits by Size
https://shopmath.org/fits/h7-r6 · data verified August 1, 2026
A 25 mm H7/r6 fit gives -41 to -7 µm of clearance — a 25.000–25.021 mm hole on a 25.028–25.041 mm shaft. Medium drive. The joint itself carries load. The shaft is always larger than the hole — assembly needs force, heat or cold. All values apply at 20 °C.
- Type
- interference
- Hole
- H7
- Shaft
- r6
- Sizes
- 13
- Standard
- ISO 286-1:2010
H7/r6 at Ø25 mm · clearance, µm
-41 … -7
- Hole
- 25.000–25.021mm
- Shaft
- 25.028–25.041mm
Negative is interference. At Ø25 mm this joint is 41 µm interference at worst case — an assembly force, not a slip fit.
H7/r6 Fit — Hole and Shaft Limits with Clearance, by Nominal Size
Both parts' limits in millimetres and the resulting clearance in micrometres. Negative clearance is interference: the shaft is larger than the hole and the joint needs force, heat or cold to assemble.
| Property | Hole, mm | Shaft, mm | Clearance, µm | Property | |||
|---|---|---|---|---|---|---|---|
| Nominal Ø | Min | Max | Min | Max | Min | Max | At this size |
| 5 mm | 5.000 | 5.012 | 5.015 | 5.023 | -23 | -3 | interference |
| 6 mm | 6.000 | 6.012 | 6.015 | 6.023 | -23 | -3 | interference |
| 8 mm | 8.000 | 8.015 | 8.019 | 8.028 | -28 | -4 | interference |
| 10 mm | 10.000 | 10.015 | 10.019 | 10.028 | -28 | -4 | interference |
| 12 mm | 12.000 | 12.018 | 12.023 | 12.034 | -34 | -5 | interference |
| 16 mm | 16.000 | 16.018 | 16.023 | 16.034 | -34 | -5 | interference |
| 20 mm | 20.000 | 20.021 | 20.028 | 20.041 | -41 | -7 | interference |
| 25 mm | 25.000 | 25.021 | 25.028 | 25.041 | -41 | -7 | interference |
| 30 mm | 30.000 | 30.021 | 30.028 | 30.041 | -41 | -7 | interference |
| 40 mm | 40.000 | 40.025 | 40.034 | 40.050 | -50 | -9 | interference |
| 50 mm | 50.000 | 50.025 | 50.034 | 50.050 | -50 | -9 | interference |
| 80 mm | 80.000 | 80.030 | 80.043 | 80.062 | -62 | -13 | interference |
| 100 mm | 100.000 | 100.035 | 100.051 | 100.073 | -73 | -16 | interference |
Minimum clearance is the largest shaft in the smallest hole; maximum clearance is the smallest shaft in the largest hole. Values apply at the ISO 286 reference temperature of 20 °C.
The Hole and Shaft Tolerances That Make the H7/r6 Fit
H7/r6 is H7 on the hole and r6 on the shaft. It is a hole-basis fit: the hole is held to one standard tolerance and the shaft is varied to change the fit — which is what you want when the hole is reamed or bored to a standard size.
Sources and Method for the H7/r6 Fit Data
- H7/r6 limitscomputed
computed from the compiled ISO 286 tables: ISO 286-1 IT grades and ISO 286-2 fundamental deviations, compiled from saucecode/ISO286 (LGPL-2.1) and parkergreene/isofits (MIT), cross-checked cell-for-cell
Verified against parkergreene/isofits ISO 286-2 limit tables (MIT); ISO 286-1 formula harness — 2067 checks passed
Computed from the standard's formulas, then checked against published tables.
- Formula
Clearance from the two tolerance bands
max clearance = hole max − shaft min min clearance = hole min − shaft max
A negative result is interference. Both are computed from the compiled ISO 286-2 deviations, not from the ISO 286-1 formula, which deviates from the published table by up to 13%.
- Assumptions
- Values apply at the ISO 286 reference temperature of 20 °C. A joint assembled hot or cold, or running hot, is not at these limits.
- The tolerances cover size only. Form, roundness, cylindricity and surface finish all affect how a fit behaves and need their own callouts.
- Dataset scope: COMPILED not computed: the ISO 286-1 formula deviates up to 13.26% from the table and is used only as a harness (warn >5%, fail >15%). EXCLUDED: shaft/hole letters s, t, u and the fits H7/s6, H7/t6, H7/u6 — no free source and an undetermined step constant in the formula.
- Data last verified
- August 1, 2026
How to Cite This H7/r6 Fit Reference
Citation
ShopMath. "H7/r6 Interference Fit — Hole and Shaft Limits by Size." ShopMath, verified August 1, 2026, https://shopmath.org/fits/h7-r6
BibTeX
@misc{shopmath-fits-h7-r6,
title = {H7/r6 Interference Fit — Hole and Shaft Limits by Size},
author = {{ShopMath}},
year = {2026},
howpublished = {\url{https://shopmath.org/fits/h7-r6}},
note = {Data verified 2026-08-01}
}Permanent URL
https://shopmath.org/fits/h7-r6
Common Questions About the H7/r6 Fit
What is the clearance of a 25 mm H7/r6 fit?
- A 25 mm H7/r6 fit has -41 to -7 µm of clearance: the hole runs 25.000 to 25.021 mm and the shaft 25.028 to 25.041 mm. A negative figure is interference — the parts must be pressed, heated or chilled together.
Is H7/r6 a clearance, transition or interference fit?
- H7/r6 is a interference fit. The shaft is always larger than the hole — assembly needs force, heat or cold. Medium drive. The joint itself carries load.
What is H7/r6 used for?
- Medium drive. The joint itself carries load. It is a hole-basis fit, so the hole is held to one standard tolerance and the shaft is machined to suit.
How does the H7/r6 fit change with size?
- Across the 13 verified nominal sizes the clearance runs from -73 µm at 100 mm to -3 µm at 5 mm, because both tolerance bands widen with nominal size.