ISO 286 · transition fit · IT6
js6 shaft tolerance
The js6 limits we cut to at every common nominal, computed from the ISO 286 fundamental deviation for js and the IT6 grade. Same numbers the configurator stamps on a js6 diameter.
js6 is a symmetric transition class: the band straddles nominal exactly, half above and half below. The letter js 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 js6 band is +.0003 to -.0003: the shaft measures between 0.9997″ and 1.0003″, a 0.0005″ window. The table gives the same limits at the inch and metric nominals we turn most.
Pick js6 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.
js6 limits by nominal diameter
| Nominal Ø | Upper dev. | Lower dev. | Max Ø (in) | Min Ø (in) | Band (in) |
|---|---|---|---|---|---|
| 1/4″ (0.25) | +.0002 | -.0002 | 0.2502 | 0.2498 | 0.0004 |
| 3/8″ (0.375) | +.0002 | -.0002 | 0.3752 | 0.3748 | 0.0004 |
| 1/2″ (0.5) | +.0002 | -.0002 | 0.5002 | 0.4998 | 0.0004 |
| 5/8″ (0.625) | +.0002 | -.0002 | 0.6252 | 0.6248 | 0.0004 |
| 3/4″ (0.75) | +.0003 | -.0003 | 0.7503 | 0.7497 | 0.0005 |
| 7/8″ (0.875) | +.0003 | -.0003 | 0.8753 | 0.8747 | 0.0005 |
| 1″ (1) | +.0003 | -.0003 | 1.0003 | 0.9997 | 0.0005 |
| 1-1/8″ (1.125) | +.0003 | -.0003 | 1.1253 | 1.1247 | 0.0005 |
| 1-1/4″ (1.25) | +.0003 | -.0003 | 1.2503 | 1.2497 | 0.0006 |
| 1-3/8″ (1.375) | +.0003 | -.0003 | 1.3753 | 1.3747 | 0.0006 |
| 1-1/2″ (1.5) | +.0003 | -.0003 | 1.5003 | 1.4997 | 0.0006 |
| 1-3/4″ (1.75) | +.0003 | -.0003 | 1.7503 | 1.7497 | 0.0006 |
| 2″ (2) | +.0004 | -.0004 | 2.0004 | 1.9996 | 0.0007 |
| 2-1/2″ (2.5) | +.0004 | -.0004 | 2.5004 | 2.4996 | 0.0007 |
| 3″ (3) | +.0004 | -.0004 | 3.0004 | 2.9996 | 0.0007 |
| 4″ (4) | +.0004 | -.0004 | 4.0004 | 3.9996 | 0.0009 |
| Metric nominals (limits in inches) | |||||
| 20 mm (0.7874″) | +.0003 | -.0003 | 0.7877 | 0.7871 | 0.0005 |
| 25 mm (0.9843″) | +.0003 | -.0003 | 0.9845 | 0.984 | 0.0005 |
| 30 mm (1.1811″) | +.0003 | -.0003 | 1.1814 | 1.1808 | 0.0005 |
| 35 mm (1.378″) | +.0003 | -.0003 | 1.3783 | 1.3776 | 0.0006 |
| 40 mm (1.5748″) | +.0003 | -.0003 | 1.5751 | 1.5745 | 0.0006 |
| 45 mm (1.7717″) | +.0003 | -.0003 | 1.772 | 1.7713 | 0.0006 |
| 50 mm (1.9685″) | +.0003 | -.0003 | 1.9688 | 1.9682 | 0.0006 |
| 55 mm (2.1654″) | +.0004 | -.0004 | 2.1657 | 2.165 | 0.0007 |
| 60 mm (2.3622″) | +.0004 | -.0004 | 2.3626 | 2.3618 | 0.0007 |
| 65 mm (2.5591″) | +.0004 | -.0004 | 2.5594 | 2.5587 | 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 js6
| Application | Finish target (Ra, µin) |
|---|---|
| Locating diameter | 16 |
Part of Shaft fits and tolerances. Other pages in the series: d9 · e8 · f7 · g6 · h6 · h7 · h8 · 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 js6 is used
These are the applications the configurator associates with js6, 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.
Transition fit, by the numbers
A js6 shaft against a nominal (H-basis) bore ranges from a slight clearance to a slight interference depending on where each part lands in its band; at 1″ the shaft itself spans 0.9997″ to 1.0003″. It seats without slop and still comes apart with an arbor press, which is the point.
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.