ISO 286 · clearance fit · IT6
g6 shaft tolerance
The g6 limits we cut to at every common nominal, computed from the ISO 286 fundamental deviation for g and the IT6 grade. Same numbers the configurator stamps on a g6 diameter.
g6 is a clearance class: the whole band sits below nominal, so the shaft always has room in a nominal-size bore. The letter g fixes where the band sits relative to nominal (the fundamental deviation); the grade 6 fixes how wide it is (IT6). Both come from the ISO 286 tables and scale with diameter, which is why one page per class, with every nominal, is more useful than a single number.
At a 1″ nominal the g6 band is -.0003 to -.0008: the shaft measures between 0.9992″ and 0.9997″, a 0.0005″ window. The table gives the same limits at the inch and metric nominals we turn most.
Pick g6 on any diameter in the configurator and the drawing carries exactly these limits; the engine computes them from the standard for the diameter you enter, not from this table.
g6 limits by nominal diameter
| Nominal Ø | Upper dev. | Lower dev. | Max Ø (in) | Min Ø (in) | Band (in) |
|---|---|---|---|---|---|
| 1/4″ (0.25) | -.0002 | -.0006 | 0.2498 | 0.2494 | 0.0004 |
| 3/8″ (0.375) | -.0002 | -.0006 | 0.3748 | 0.3744 | 0.0004 |
| 1/2″ (0.5) | -.0002 | -.0007 | 0.4998 | 0.4993 | 0.0004 |
| 5/8″ (0.625) | -.0002 | -.0007 | 0.6248 | 0.6243 | 0.0004 |
| 3/4″ (0.75) | -.0003 | -.0008 | 0.7497 | 0.7492 | 0.0005 |
| 7/8″ (0.875) | -.0003 | -.0008 | 0.8747 | 0.8742 | 0.0005 |
| 1″ (1) | -.0003 | -.0008 | 0.9997 | 0.9992 | 0.0005 |
| 1-1/8″ (1.125) | -.0003 | -.0008 | 1.1247 | 1.1242 | 0.0005 |
| 1-1/4″ (1.25) | -.0004 | -.0010 | 1.2496 | 1.249 | 0.0006 |
| 1-3/8″ (1.375) | -.0004 | -.0010 | 1.3746 | 1.374 | 0.0006 |
| 1-1/2″ (1.5) | -.0004 | -.0010 | 1.4996 | 1.499 | 0.0006 |
| 1-3/4″ (1.75) | -.0004 | -.0010 | 1.7496 | 1.749 | 0.0006 |
| 2″ (2) | -.0004 | -.0011 | 1.9996 | 1.9989 | 0.0007 |
| 2-1/2″ (2.5) | -.0004 | -.0011 | 2.4996 | 2.4989 | 0.0007 |
| 3″ (3) | -.0004 | -.0011 | 2.9996 | 2.9989 | 0.0007 |
| 4″ (4) | -.0005 | -.0013 | 3.9995 | 3.9987 | 0.0009 |
| Metric nominals (limits in inches) | |||||
| 20 mm (0.7874″) | -.0003 | -.0008 | 0.7871 | 0.7866 | 0.0005 |
| 25 mm (0.9843″) | -.0003 | -.0008 | 0.984 | 0.9835 | 0.0005 |
| 30 mm (1.1811″) | -.0003 | -.0008 | 1.1808 | 1.1803 | 0.0005 |
| 35 mm (1.378″) | -.0004 | -.0010 | 1.3776 | 1.377 | 0.0006 |
| 40 mm (1.5748″) | -.0004 | -.0010 | 1.5744 | 1.5738 | 0.0006 |
| 45 mm (1.7717″) | -.0004 | -.0010 | 1.7713 | 1.7707 | 0.0006 |
| 50 mm (1.9685″) | -.0004 | -.0010 | 1.9681 | 1.9675 | 0.0006 |
| 55 mm (2.1654″) | -.0004 | -.0011 | 2.165 | 2.1642 | 0.0007 |
| 60 mm (2.3622″) | -.0004 | -.0011 | 2.3618 | 2.3611 | 0.0007 |
| 65 mm (2.5591″) | -.0004 | -.0011 | 2.5587 | 2.5579 | 0.0007 |
Deviations from nominal in inches at 0.0001 in resolution; max and min are the finished diameter limits. Metric nominals are converted and the limits shown in inches.
Applications and finish targets for g6
| Application | Finish target (Ra, µin) |
|---|---|
| Bearing seat (inner ring on a rotating shaft) | 32 |
| Bushing or sleeve journal | 16 |
Part of Shaft fits and tolerances. Other pages in the series: d9 · e8 · f7 · h6 · h7 · h8 · js6 · j6 · k5 · k6 · m6 · n6 · p6 · r6 · s6 · 1/4″ · 3/8″ · 1/2″ · 5/8″ · 3/4″ · 7/8″ · 1″ · 1-1/8″ · 1-1/4″ · 1-3/8″ · 1-1/2″ · 1-3/4″ · 2″ · 2-1/2″ · 3″ · 4″ · 20 mm · 25 mm · 30 mm · 35 mm · 40 mm · 45 mm · 50 mm · 55 mm · 60 mm · 65 mm.
Where g6 is used
These are the applications the configurator associates with g6, with the surface-finish target it applies to that diameter. A fit class sets size; the finish is what makes the size hold in service.
Clearance fit, by the numbers
Every g6 limit is at or below nominal, so against a nominal (H-basis) bore the minimum gap is 0.0003″ and the maximum is set by the bore's own tolerance plus 0.0008″ at 1″. Tighter grades narrow the shaft's share of that range.
Frequently Asked Questions
These references are for specifying a part; every value here is one the configurator applies when you build one. Numbers are representative of the standard; check them against your part and its mating components before ordering. See all guides on the guides page.