ISO 286 · clearance fit · shaft basis
F8/h7 Clearance Fit — Hole and Shaft Limits by Size
https://shopmath.org/fits/f8-h7 · data verified August 1, 2026
A 25 mm F8/h7 fit gives +20 to +74 µm of clearance — a 25.020–25.053 mm hole on a 24.979–25.000 mm shaft. Close running, shaft basis. The hole is always larger than the shaft — the parts always assemble with a gap. All values apply at 20 °C.
- Type
- clearance
- Hole
- F8
- Shaft
- h7
- Sizes
- 13
- Standard
- ISO 286-1:2010
F8/h7 at Ø25 mm · clearance, µm
+20 … +74
- Hole
- 25.020–25.053mm
- Shaft
- 24.979–25.000mm
Clearance at Ø25 mm, at 20 °C. Every other verified size is in the table below.
F8/h7 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 | 5.010 | 5.028 | 4.988 | 5.000 | +10 | +40 | clearance |
| 6 mm | 6.010 | 6.028 | 5.988 | 6.000 | +10 | +40 | clearance |
| 8 mm | 8.013 | 8.035 | 7.985 | 8.000 | +13 | +50 | clearance |
| 10 mm | 10.013 | 10.035 | 9.985 | 10.000 | +13 | +50 | clearance |
| 12 mm | 12.016 | 12.043 | 11.982 | 12.000 | +16 | +61 | clearance |
| 16 mm | 16.016 | 16.043 | 15.982 | 16.000 | +16 | +61 | clearance |
| 20 mm | 20.020 | 20.053 | 19.979 | 20.000 | +20 | +74 | clearance |
| 25 mm | 25.020 | 25.053 | 24.979 | 25.000 | +20 | +74 | clearance |
| 30 mm | 30.020 | 30.053 | 29.979 | 30.000 | +20 | +74 | clearance |
| 40 mm | 40.025 | 40.064 | 39.975 | 40.000 | +25 | +89 | clearance |
| 50 mm | 50.025 | 50.064 | 49.975 | 50.000 | +25 | +89 | clearance |
| 80 mm | 80.030 | 80.076 | 79.970 | 80.000 | +30 | +106 | clearance |
| 100 mm | 100.036 | 100.090 | 99.965 | 100.000 | +36 | +125 | clearance |
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 F8/h7 Fit
F8/h7 is F8 on the hole and h7 on the shaft. It is a shaft-basis fit: the shaft is held to one standard tolerance and the hole is varied — which is what you want when the shaft is a drawn or ground bar bought to size.
Sources and Method for the F8/h7 Fit Data
- F8/h7 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 F8/h7 Fit Reference
Citation
ShopMath. "F8/h7 Clearance Fit — Hole and Shaft Limits by Size." ShopMath, verified August 1, 2026, https://shopmath.org/fits/f8-h7
BibTeX
@misc{shopmath-fits-f8-h7,
title = {F8/h7 Clearance Fit — Hole and Shaft Limits by Size},
author = {{ShopMath}},
year = {2026},
howpublished = {\url{https://shopmath.org/fits/f8-h7}},
note = {Data verified 2026-08-01}
}Permanent URL
https://shopmath.org/fits/f8-h7
Common Questions About the F8/h7 Fit
What is the clearance of a 25 mm F8/h7 fit?
- A 25 mm F8/h7 fit has +20 to +74 µm of clearance: the hole runs 25.020 to 25.053 mm and the shaft 24.979 to 25.000 mm.
Is F8/h7 a clearance, transition or interference fit?
- F8/h7 is a clearance fit. The hole is always larger than the shaft — the parts always assemble with a gap. Close running, shaft basis.
What is F8/h7 used for?
- Close running, shaft basis. It is a shaft-basis fit, so the shaft is held to one standard tolerance and the hole is machined to suit.
How does the F8/h7 fit change with size?
- Across the 13 verified nominal sizes the clearance runs from +10 µm at 5 mm to +125 µm at 100 mm, because both tolerance bands widen with nominal size.