Close running fit of ordinary accuracy; used like H7/f7 but with a less demanding hole: shafts and bushings in general machinery, pump and fan shafts.
Deviations of hole H8 and shaft f7, and the resulting maximum / minimum clearance (negative values mean interference). Nominal sizes 0–500 mm, values in mm.
| Nominal size (mm) | Hole H8 (upper / lower) | Shaft f7 (upper / lower) | Max. clearance | Min. clearance | Fit type |
|---|---|---|---|---|---|
| 0 ~ 3 | +0.014 / 0 | -0.006 / -0.016 | clearance 0.030 | clearance 0.006 | Clearance |
| >3 ~ 6 | +0.018 / 0 | -0.010 / -0.022 | clearance 0.040 | clearance 0.010 | Clearance |
| >6 ~ 10 | +0.022 / 0 | -0.013 / -0.028 | clearance 0.050 | clearance 0.013 | Clearance |
| >10 ~ 18 | +0.027 / 0 | -0.016 / -0.034 | clearance 0.061 | clearance 0.016 | Clearance |
| >18 ~ 30 | +0.033 / 0 | -0.020 / -0.041 | clearance 0.074 | clearance 0.020 | Clearance |
| >30 ~ 50 | +0.039 / 0 | -0.025 / -0.050 | clearance 0.089 | clearance 0.025 | Clearance |
| >50 ~ 80 | +0.046 / 0 | -0.030 / -0.060 | clearance 0.106 | clearance 0.030 | Clearance |
| >80 ~ 120 | +0.054 / 0 | -0.036 / -0.071 | clearance 0.125 | clearance 0.036 | Clearance |
| >120 ~ 180 | +0.063 / 0 | -0.043 / -0.083 | clearance 0.146 | clearance 0.043 | Clearance |
| >180 ~ 250 | +0.072 / 0 | -0.050 / -0.096 | clearance 0.168 | clearance 0.050 | Clearance |
| >250 ~ 315 | +0.081 / 0 | -0.056 / -0.108 | clearance 0.189 | clearance 0.056 | Clearance |
| >315 ~ 400 | +0.089 / 0 | -0.062 / -0.119 | clearance 0.208 | clearance 0.062 | Clearance |
| >400 ~ 500 | +0.097 / 0 | -0.068 / -0.131 | clearance 0.228 | clearance 0.068 | Clearance |
Max. clearance = hole upper deviation − shaft lower deviation; min. clearance = hole lower deviation − shaft upper deviation; a negative result is an interference. Each row applies to the whole size range shown.
The hole is the datum (H, lower deviation 0) and different fits are obtained by changing the shaft tolerance. Holes are made with fixed-size tools such as reamers and drills, which are costly, so keeping the hole and varying the shaft is more economical; the hole-basis system is therefore generally preferred.
It is a clearance fit (hole-basis system). Close running fit of ordinary accuracy; used like H7/f7 but with a less demanding hole: shafts and bushings in general machinery, pump and fan shafts.
The H8 hole is made to 10(+0.022/0) and the f7 shaft to 10(-0.013/-0.028). At the loosest that gives clearance 0.050, at the tightest clearance 0.013 (mm).
Stock dowel pins come in h6, h7, m6 (plus tolerance) and minus tolerance (0/-0.02). Put the hole tolerance (H8) and the application in your enquiry and we will tell you which one fits as it is.
Values follow ISO 286-1; the table was cross-checked cell by cell against three independent sources on 2026-08-26 (6,674 cells agree, 0 errors). Coverage: shafts a–z and the corresponding uppercase holes, IT1–IT13, nominal sizes 0–500 mm. cd/ef/fg/za/zb/zc, sizes above 500 mm and grades above IT13 are not included: the tool reports "not found" and never extrapolates. Data sources and verification →