Bright bars (cold finished) · Size & tolerance table

Bright bar tolerances: ISO 286 h6 to h13

Standard: ISO 286-1 / ISO 286-2 (tolerance grades) · EN 10278 · EN ISO 683-7

Bright bars are ordered to an ISO tolerance class. The letter h means the upper deviation is zero: the bar may be smaller than the nominal size by up to the amount shown, never larger. The number is the IT grade — the smaller the number, the tighter the tolerance and the more finishing it needs.

As a rule of thumb, cold-drawn rounds are supplied to h9–h11, turned or peeled rounds to h10–h11, and ground (centreless ground) rounds to h6–h9; hexagons, squares and flats are usually h11 or h12. Check the delivery standard and state the class on the order.

Lower deviation for the h tolerance zone (upper deviation 0)

Nominal size mm	h6 mm	h7 mm	h8 mm	h9 mm	h10 mm	h11 mm	h12 mm	h13 mm
up to 3	−0.006	−0.010	−0.014	−0.025	−0.040	−0.060	−0.100	−0.140
over 3 to 6	−0.008	−0.012	−0.018	−0.030	−0.048	−0.075	−0.120	−0.180
over 6 to 10	−0.009	−0.015	−0.022	−0.036	−0.058	−0.090	−0.150	−0.220
over 10 to 18	−0.011	−0.018	−0.027	−0.043	−0.070	−0.110	−0.180	−0.270
over 18 to 30	−0.013	−0.021	−0.033	−0.052	−0.084	−0.130	−0.210	−0.330
over 30 to 50	−0.016	−0.025	−0.039	−0.062	−0.100	−0.160	−0.250	−0.390
over 50 to 80	−0.019	−0.030	−0.046	−0.074	−0.120	−0.190	−0.300	−0.460
over 80 to 120	−0.022	−0.035	−0.054	−0.087	−0.140	−0.220	−0.350	−0.540
over 120 to 180	−0.025	−0.040	−0.063	−0.100	−0.160	−0.250	−0.400	−0.630
over 180 to 250	−0.029	−0.046	−0.072	−0.115	−0.185	−0.290	−0.460	−0.720

Notes

Example: a 25 mm round to h9 may measure from 24.948 to 25.000 mm.
The values are the ISO 286 standard tolerances IT6–IT13 for each size range.