{"id":6954,"date":"2026-06-10T13:18:02","date_gmt":"2026-06-10T13:18:02","guid":{"rendered":"https:\/\/rapidcision.com\/?p=6954"},"modified":"2026-06-08T19:35:49","modified_gmt":"2026-06-08T19:35:49","slug":"cnc-tolerance-chart-iso-2768","status":"publish","type":"post","link":"https:\/\/rapidcision.com\/ja\/cnc-tolerance-chart-iso-2768\/","title":{"rendered":"CNC Machining Tolerance Chart: ISO 2768 General Tolerances Explained"},"content":{"rendered":"<p><i><span style=\"font-weight: 400;\">Rapidcision\u30a8\u30f3\u30b8\u30cb\u30a2\u30ea\u30f3\u30b0\u30c1\u30fc\u30e0\u306b\u3088\u308b\u30ec\u30d3\u30e5\u30fc | \u6700\u7d42\u66f4\u65b0\u65e5\uff1a2026\u5e746\u6708<\/span><\/i><\/p>\n<p><span style=\"font-weight: 400;\">A CNC machining tolerance chart tells you the permissible variation allowed on a dimension that does not carry its own explicit tolerance. On most engineering drawings, that default comes from ISO 2768, an international standard you invoke with a single note in the title block, such as ISO 2768-mK. That one callout sets the allowed deviation for every untoleranced length, diameter, angle, and form feature on the part, which keeps a drawing clean and removes the guesswork that would otherwise leave each shop to interpret loose dimensions differently.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The tables below give the full ISO 2768 values for linear dimensions, radii and chamfers, angles, and geometrical features, in millimeters. Use them to read a drawing, to pick the right class for a new design, and to avoid the expensive habit of tightening tolerances that do not need to be tight. We apply these defaults across our<\/span><a href=\"https:\/\/rapidcision.com\/ja\/cnc-machining\/\"> <span style=\"font-weight: 400;\">CNC\u52a0\u5de5\u30b5\u30fc\u30d3\u30b9<\/span><\/a><span style=\"font-weight: 400;\">, and a clear title-block callout makes your quote and your parts more predictable.<\/span><\/p>\n<h2><b>What ISO 2768 Covers<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">ISO 2768 is published by the International Organization for Standardization and is the dominant general tolerance standard in Europe and Asia, recognized by CNC suppliers worldwide. It is also published as DIN 7168 in Germany. The standard comes in two parts that work together:<\/span><\/p>\n<ul>\n<li><span style=\"font-weight: 400;\"> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 <\/span><b>ISO 2768-1<\/b><span style=\"font-weight: 400;\"> sets general tolerances for linear and angular dimensions, including lengths, diameters, step sizes, external radii, chamfer heights, and angles. It offers four classes: fine (f), medium (m), coarse (c), and very coarse (v).<\/span><\/li>\n<li><span style=\"font-weight: 400;\"> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 <\/span><b>ISO 2768-2<\/b><span style=\"font-weight: 400;\"> sets general geometrical tolerances for straightness, flatness, perpendicularity, symmetry, and circular run-out. It offers three classes: H, K, and L, with H the most precise.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">It applies to parts made by material removal such as milling, turning, drilling, and grinding, and to sheet metal parts. It does not govern thread tolerances, surface roughness, or any dimension that already has its own explicit tolerance, since an explicit callout always takes precedence.<\/span><\/p>\n<h2><b>ISO 2768-1: Linear Dimensions<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">Permissible deviations in millimeters.<\/span><\/p>\n<table>\n<tbody>\n<tr>\n<td><span style=\"font-weight: 400;\">Nominal size range (mm)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Fine (f)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Medium (m)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Coarse (c)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Very Coarse (v)<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">0.5 to 3<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.05<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.1<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u2014<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 3 to 6<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.05<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.1<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.3<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.5<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 6 to 30<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.1<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11.0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 30 to 120<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.15<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.3<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.8<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11.5<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 120 to 400<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b12.5<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 400 to 1000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.3<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.8<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b12.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b14.0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 1000 to 2000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b13.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b16.0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 2000 to 4000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u2014<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b12.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b14.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b18.0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span style=\"font-weight: 400;\">For nominal sizes below 0.5 mm, deviations are indicated next to the relevant dimension.<\/span><\/p>\n<h2><b>ISO 2768-1: External Radii and Chamfer Heights<\/b><\/h2>\n<table>\n<tbody>\n<tr>\n<td><span style=\"font-weight: 400;\">Nominal size range (mm)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Fine (f)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Medium (m)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Coarse (c)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Very Coarse (v)<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">0.5 to 3<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.4<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.4<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 3 to 6<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11.0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 6<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b12.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b12.0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><b>ISO 2768-1: Angular Dimensions<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">Permissible deviation by the length of the shorter side of the angle.<\/span><\/p>\n<table>\n<tbody>\n<tr>\n<td><span style=\"font-weight: 400;\">Shorter side length (mm)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Fine (f)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Medium (m)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Coarse (c)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">Very Coarse (v)<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">up to 10<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11\u00b0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11\u00b0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11\u00b030\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b13\u00b0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 10 to 50<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b030\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b030\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11\u00b0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b12\u00b0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 50 to 120<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b020\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b020\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b030\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b11\u00b0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 120 to 400<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b010\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b010\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b015\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b030\u2032<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 400<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b05\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b05\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b010\u2032<\/span><\/td>\n<td><span style=\"font-weight: 400;\">\u00b10\u00b020\u2032<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><b>ISO 2768-2: Geometrical Tolerances<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">These control form and position. Values are in millimeters. Note that ISO 2768-2 does not cover parallelism, cylindricity, concentricity, profile, or true position, which all require explicit GD&amp;T callouts.<\/span><\/p>\n<p><b>Straightness and flatness<\/b><span style=\"font-weight: 400;\"> (by nominal length)<\/span><\/p>\n<table>\n<tbody>\n<tr>\n<td><span style=\"font-weight: 400;\">Nominal length range (mm)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">H<\/span><\/td>\n<td><span style=\"font-weight: 400;\">K<\/span><\/td>\n<td><span style=\"font-weight: 400;\">L<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">up to 10<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.02<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.05<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.1<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 10 to 30<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.05<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.1<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.2<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 30 to 100<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.1<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.4<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 100 to 300<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.4<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.8<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 300 to 1000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.3<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.6<\/span><\/td>\n<td><span style=\"font-weight: 400;\">1.2<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 1000 to 3000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.4<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.8<\/span><\/td>\n<td><span style=\"font-weight: 400;\">1.6<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><b>Perpendicularity<\/b><span style=\"font-weight: 400;\"> (by length of the shorter side)<\/span><\/p>\n<table>\n<tbody>\n<tr>\n<td><span style=\"font-weight: 400;\">Shorter side range (mm)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">H<\/span><\/td>\n<td><span style=\"font-weight: 400;\">K<\/span><\/td>\n<td><span style=\"font-weight: 400;\">L<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">up to 100<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.4<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.6<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 100 to 300<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.3<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.6<\/span><\/td>\n<td><span style=\"font-weight: 400;\">1.0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 300 to 1000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.4<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.8<\/span><\/td>\n<td><span style=\"font-weight: 400;\">1.5<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 1000 to 3000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">1.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">2.0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><b>Symmetry<\/b><\/p>\n<table>\n<tbody>\n<tr>\n<td><span style=\"font-weight: 400;\">Nominal length range (mm)<\/span><\/td>\n<td><span style=\"font-weight: 400;\">H<\/span><\/td>\n<td><span style=\"font-weight: 400;\">K<\/span><\/td>\n<td><span style=\"font-weight: 400;\">L<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">up to 100<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.6<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.6<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 100 to 300<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.6<\/span><\/td>\n<td><span style=\"font-weight: 400;\">1.0<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 300 to 1000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.8<\/span><\/td>\n<td><span style=\"font-weight: 400;\">1.5<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">over 1000 to 3000<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.5<\/span><\/td>\n<td><span style=\"font-weight: 400;\">1.0<\/span><\/td>\n<td><span style=\"font-weight: 400;\">2.0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><b>Circular run-out<\/b><\/p>\n<table>\n<tbody>\n<tr>\n<td><span style=\"font-weight: 400;\">H<\/span><\/td>\n<td><span style=\"font-weight: 400;\">K<\/span><\/td>\n<td><span style=\"font-weight: 400;\">L<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400;\">0.1<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.2<\/span><\/td>\n<td><span style=\"font-weight: 400;\">0.5<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><b>How to Read ISO 2768-mK<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">A combined callout pairs one class from each part. In ISO 2768-mK, the lowercase <\/span><b>m<\/b><span style=\"font-weight: 400;\"> is the medium linear class from Part 1, and the uppercase <\/span><b>K<\/b><span style=\"font-weight: 400;\"> is the medium geometrical class from Part 2. So an untoleranced 25 mm dimension on an ISO 2768-mK drawing carries \u00b10.2 mm, because 25 mm falls in the over-6-to-30 range of the medium column. A flatness callout on a 200 mm face would allow 0.4 mm under the K class.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">ISO 2768-mK is the most common general tolerance on <a href=\"https:\/\/rapidcision.com\/ja\/cnc-machining\/\">CNC\u52a0\u5de5<\/a> and sheet metal drawings, because the medium classes match what a capable machine holds without special effort.<\/span><\/p>\n<h2><b>Choosing the Right Class<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">Pick the loosest class that still lets the part function. Tighter is not better, it is more expensive.<\/span><\/p>\n<ul>\n<li><span style=\"font-weight: 400;\"> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 <\/span><b>Fine (f) and H<\/b><span style=\"font-weight: 400;\"> for precision features, mating surfaces, and parts with tight fits.<\/span><\/li>\n<li><span style=\"font-weight: 400;\"> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 <\/span><b>Medium (m) and K<\/b><span style=\"font-weight: 400;\"> for general machined and sheet metal parts. This is the default for most work.<\/span><\/li>\n<li><span style=\"font-weight: 400;\"> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 <\/span><b>Coarse (c) and L<\/b><span style=\"font-weight: 400;\"> for non-critical parts such as covers, brackets, and enclosures where fit is not demanding.<\/span><\/li>\n<li><span style=\"font-weight: 400;\"> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 <\/span><b>Very coarse (v)<\/b><span style=\"font-weight: 400;\"> for rough parts, flame-cut pieces, and castings, rarely used for CNC work.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Specifying tighter than necessary inflates machining time and cost, while specifying looser than the part needs causes assembly failures. The right call is to tighten only the features that matter and let the general tolerance handle the rest.<\/span><\/p>\n<h2><b>ISO 2768 vs Explicit GD&amp;T<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">ISO 2768 is a safety net for the dimensions you did not individually tolerance. It is not a substitute for GD&amp;T where function demands control. Any dimension with its own explicit tolerance overrides the general default, and features that need position, cylindricity, concentricity, or profile control must be called out explicitly, since ISO 2768-2 does not cover them. The practical pattern on a good drawing is a single ISO 2768 note in the title block, with explicit tolerances and GD&amp;T applied only to the critical features.<\/span><\/p>\n<h2><b>Rapidcision\u306e\u6d3b\u7528\u30b7\u30fc\u30f3<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">When you upload a drawing for an instant quote, the ISO 2768 class in your title block tells us how to treat every untoleranced feature, which makes pricing and production predictable. If your part has critical features, call them out explicitly and let the general tolerance cover the rest, and our DFM feedback will flag anything that looks tighter than it needs to be. Review capability on our<\/span><a href=\"https:\/\/rapidcision.com\/ja\/cnc-machining\/\"> <span style=\"font-weight: 400;\">CNC\u52a0\u5de5\u30b5\u30fc\u30d3\u30b9<\/span><\/a><span style=\"font-weight: 400;\">, see how finish ties in on our<\/span><a href=\"https:\/\/rapidcision.com\/ja\/surface-roughness-chart\/\"> <span style=\"font-weight: 400;\">surface roughness chart<\/span><\/a><span style=\"font-weight: 400;\">, or<\/span><a href=\"https:\/\/rapidcision.com\/ja\/get-a-quote\/\"> <span style=\"font-weight: 400;\">upload your CAD file for a quote<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n<h2><b>\u3088\u304f\u3042\u308b\u8cea\u554f<\/b><\/h2>\n<p><b>What is ISO 2768?<\/b><span style=\"font-weight: 400;\"> ISO 2768 is an international standard that defines general tolerances for dimensions on a drawing that do not have their own explicit tolerance. A single title-block note, such as ISO 2768-mK, sets the default permissible variation for all untoleranced features.<\/span><\/p>\n<p><b>What does ISO 2768-mK mean?<\/b><span style=\"font-weight: 400;\"> It pairs the medium linear class (m) from ISO 2768-1 with the medium geometrical class (K) from ISO 2768-2. It is the most common general tolerance callout for CNC machined and sheet metal parts.<\/span><\/p>\n<p><b>What tolerance does ISO 2768 medium give for a 25 mm dimension?<\/b><span style=\"font-weight: 400;\"> Under the medium (m) class, a 25 mm dimension carries \u00b10.2 mm, because it falls in the over-6-to-30 mm range. The deviation depends on which size range the dimension falls into.<\/span><\/p>\n<p><b>Which ISO 2768 class should I use for CNC parts?<\/b><span style=\"font-weight: 400;\"> Medium (m) with K geometrical tolerances suits most CNC work, since it matches what a capable machine holds economically. Use fine (f) and H for precision features, and coarse (c) or L for non-critical parts.<\/span><\/p>\n<p><b>Does ISO 2768 cover all geometric tolerances?<\/b><span style=\"font-weight: 400;\"> No. ISO 2768-2 covers straightness, flatness, perpendicularity, symmetry, and circular run-out. Parallelism, cylindricity, concentricity, profile, and true position require explicit GD&amp;T callouts.<\/span><\/p>\n<p><b>Does an explicit tolerance override ISO 2768?<\/b><span style=\"font-weight: 400;\"> Yes. Any dimension with its own stated tolerance takes precedence over the general ISO 2768 default. The general tolerance only applies to features without an individual callout.<\/span><\/p>\n<h2><b>Using the Tolerance Chart<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">ISO 2768 keeps drawings clean and unambiguous by setting sensible default tolerances with a single callout, most often ISO 2768-mK. Read your dimension\u2019s size range against the right class, tighten only the features that need it, and use explicit GD&amp;T where function demands. That approach holds quality where it matters and keeps cost down everywhere else.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">If you have a part to make,<\/span><a href=\"https:\/\/rapidcision.com\/ja\/get-a-quote\/\"> <span style=\"font-weight: 400;\">upload your drawing for an instant quote<\/span><\/a><span style=\"font-weight: 400;\">. We will apply your ISO 2768 class to the general dimensions and confirm the critical tolerances with DFM feedback.<\/span><\/p>","protected":false},"excerpt":{"rendered":"<p>Reviewed by the Rapidcision Engineering Team | Last updated: June 2026 A CNC machining tolerance chart tells you the permissible variation allowed on a dimension that does not carry its own explicit tolerance. On most engineering drawings, that default comes from ISO 2768, an international standard you invoke with a single note in the title block, such as ISO 2768-mK. That one callout sets the allowed deviation for every untoleranced length, diameter, angle, and form feature on the part, which keeps a drawing clean and removes the guesswork that would otherwise leave each shop to interpret loose dimensions differently. The tables below give the full ISO 2768 values for linear [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":6955,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15,11],"tags":[],"class_list":["post-6954","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-cnc-machining"],"_links":{"self":[{"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/posts\/6954","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/comments?post=6954"}],"version-history":[{"count":2,"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/posts\/6954\/revisions"}],"predecessor-version":[{"id":7288,"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/posts\/6954\/revisions\/7288"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/media\/6955"}],"wp:attachment":[{"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/media?parent=6954"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/categories?post=6954"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rapidcision.com\/ja\/wp-json\/wp\/v2\/tags?post=6954"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}