Gdt Tolerance Zones: it grade by size
it grade 180 250 IT8 to it grade 30 50 IT9
GD&T tolerance zone data per ASME Y14.5-2018 and ISO 286-1:2010 — covering IT tolerance grades (IT1-IT14) with tabulated values in micrometers for nominal sizes 0-500mm; position tolerance at MMC using floating fastener formula T=H-F and fixed fastener formula T=(H-F)/2 for M3-M12 bolts per ISO 273 clearance holes; MMC bonus tolerance examples; datum feature simulators (RFS/RMB, MMB, LMB) per ASME Y14.5-2018 Section 7.11; profile tolerance zone types (bilateral, unilateral outside/inside, unequally disposed); geometric tolerance zone shapes (cylindrical, total width, spherical); and typical IT grades achievable by manufacturing process (lapping, grinding, turning, milling, drilling, casting).
| tolerance type | record id | description | it grade | nominal size lower mm (mm) | nominal size upper mm (mm) | process category | standard | tolerance value um (um) |
|---|---|---|---|---|---|---|---|---|
| it grade by size | it grade 180 250 IT8 | IT8 tolerance 180-250mm | IT8 | 180 | 250 | milling turning | ISO 286-1:2010 Table 1 | 72 |
| it grade by size | it grade 18 30 IT6 | IT6 tolerance 18-30mm | IT6 | 18 | 30 | lapping honing | ISO 286-1:2010 Table 1 | 13 |
| it grade by size | it grade 18 30 IT7 | IT7 tolerance 18-30mm | IT7 | 18 | 30 | precision machining | ISO 286-1:2010 Table 1 | 21 |
| it grade by size | it grade 18 30 IT8 | IT8 tolerance 18-30mm | IT8 | 18 | 30 | milling turning | ISO 286-1:2010 Table 1 | 33 |
| it grade by size | it grade 18 30 IT9 | IT9 tolerance 18-30mm | IT9 | 18 | 30 | drilling | ISO 286-1:2010 Table 1 | 52 |
| it grade by size | it grade 250 315 IT7 | IT7 tolerance 250-315mm | IT7 | 250 | 315 | precision machining | ISO 286-1:2010 Table 1 | 52 |
| it grade by size | it grade 30 50 IT6 | IT6 tolerance 30-50mm | IT6 | 30 | 50 | lapping honing | ISO 286-1:2010 Table 1 | 16 |
| it grade by size | it grade 30 50 IT7 | IT7 tolerance 30-50mm | IT7 | 30 | 50 | precision machining | ISO 286-1:2010 Table 1 | 25 |
| it grade by size | it grade 30 50 IT8 | IT8 tolerance 30-50mm | IT8 | 30 | 50 | milling turning | ISO 286-1:2010 Table 1 | 39 |
| it grade by size | it grade 30 50 IT9 | IT9 tolerance 30-50mm | IT9 | 30 | 50 | drilling | ISO 286-1:2010 Table 1 | 62 |
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