{"id":2943,"date":"2026-06-16T09:10:34","date_gmt":"2026-06-16T01:10:34","guid":{"rendered":"https:\/\/jtlcnc.com\/?p=2943"},"modified":"2026-06-16T09:10:35","modified_gmt":"2026-06-16T01:10:35","slug":"what-is-the-accuracy-grade-standard-for-granite-square-boxes","status":"publish","type":"post","link":"https:\/\/jtlcnc.com\/ru\/2026\/06\/16\/what-is-the-accuracy-grade-standard-for-granite-square-boxes\/","title":{"rendered":"What is the accuracy grade standard for granite square boxes?"},"content":{"rendered":"<p>I. Executive Standards<br>Manufacturing Standard: JB\/T 10027-2017 &#8220;Granite Surface Plates, Straight Edges, Squares, and Square Boxes&#8221;<br>Verification Standard: JJG 117-2013 &#8220;Verification Regulation for Surface Plates&#8221;<br>Accuracy Grade: Grade 000, Grade 00, Grade 0 (the smaller the number, the higher the accuracy); some scenarios still use the old standard Grade 1 (General Industrial Grade).<\/p>\n\n\n\n<p>II. Grade Definitions and Applications<br>Grade 000 (Reference Grade): Metrology rooms \/ Constant temperature laboratories, used for value transfer and standard calibration.<br>Grade 00 (Precision Grade): Precision quality inspection, CMM debugging, mold \/ aerospace part inspection.<br>Grade 0 (Industrial Grade): Workshop on-site inspection, marking, machine tool alignment.<br>Grade 1 (General Grade, Old Standard): General machining, fitter marking.<\/p>\n\n\n\n<p>III. Core Tolerances (Unit: \u03bcm, Typical values for 200\u00d7200\u00d7200mm)<br>\u0422\u0430\u0431\u043b\u0438\u0446\u0430<br>Accuracy Grade | Working Surface Flatness | Relative Surface Parallelism | Adjacent Surface Perpendicularity<br>Grade 000 | 1.5 | 2 | 2<br>Grade 00 | 1.5 | 2 | 2<br>Grade 0 | 3 | 4 | 4<\/p>\n\n\n\n<p>IV. Tolerance Patterns<br>The larger the size, the larger the tolerance (e.g., 400\u00d7400\u00d7400mm: Grade 00 perpendicularity \u2248 3\u03bcm, Grade 0 \u2248 6\u03bcm).<br>Temperature Reference: Verification \/ usage temperature 20\u00b12\u2103 to avoid thermal expansion and contraction affecting accuracy.<\/p>\n\n\n\n<p>V. Difference from Squares<br>Square: Single-sided \/ double-sided right-angle reference, focusing on flatness right angle.<br>Square Box: Six-sided three-dimensional reference, fully controlling flatness, parallelism, and perpendicularity, can be flipped and used on multiple sides.<\/p>\n\n\n\n<p>VI. Selection Recommendations<br>Metrology Calibration \u2192 Grade 000<br>Precision Inspection \u2192 Grade 00<br>Workshop On-site \u2192 Grade 0<br>General Marking \u2192 Grade 1<\/p>\n\n\n\n<p>Granite Square Block Tolerance Quick Reference Table (Based on JB\/T 10027-2017) Unit: \u03bcm, Standard Calibration Temperature: (20\\pm2^\\circ\\text{C})<br>Dimensions: Length \u00d7 Width \u00d7 Height (Cubic square block, mainstream industrial specifications)<br>Controlled Items: Flatness of working surface, Parallelism of opposite faces, Perpendicularity of adjacent faces<br>I. Complete Tolerance Table<br>Table Specifications (mm) Accuracy Grade Flatness Parallelism Perpendicularity<br>100\u00d7100\u00d7100 000 Grade 0.8 1.0 1.0<br>100\u00d7100\u00d7100 00 Grade 1.2 1.5 1.5<br>100\u00d7100\u00d7100 0 Grade 2.0 2.5 2.5<br>150\u00d7150\u00d7150 000 Grade 1.0 1.2 1.2<br>150\u00d7150\u00d7150 00 Grade 1.5 2.0 2.0<br>150\u00d7150\u00d7150 0 Grade 2.5 3.0 3.0<br>200\u00d7200\u00d7200 000 Grade 1.5 2.0 2.0<br>200\u00d7200\u00d7200 00 Grade 1.5 2.0 2.0<br>200\u00d7200\u00d7200 0 Grade 3.0 4.0 4.0<br>250\u00d7250\u00d7250 000 Grade 1.8 2.2 2.2<br>250\u00d7250\u00d7250 00 Grade 2.0 2.5 2.5<br>250\u00d7250\u00d7250 0 Grade 3.5 4.5 4.5<br>300\u00d7300\u00d7300 000 Grade 2.0 2.5 2.5<br>300\u00d7300\u00d7300 00 Grade 2.5 3.0 3.0<br>300\u00d7300\u00d7300 0 Grade 4.0 5.0 5.0<br>400\u00d7400\u00d7400 000 Grade 2.5 3.0 3.0<br>400\u00d7400\u00d7400 00 Grade 3.0 3.5 3.5<br>400\u00d7400\u00d7400 0 Grade 5.0 6.0 6.0<br>500\u00d7500\u00d7500 000 Grade 3.0 3.5 3.5<br>500\u00d7500\u00d7500 00 Grade 3.5 4.0 4.0<br>500\u00d7500\u00d7500 0 Grade 6.0 7.0 7.0<br>630\u00d7630\u00d7630 000 Grade 3.8 4.2 4.2<br>630\u00d7630\u00d7630 00 Grade 4.2 4.8 4.8<br>630\u00d7630\u00d7630 0 Grade 7.0 8.0 8.0<br>II. Supplementary Notes<br>Tolerance Pattern<br>The larger the external dimensions of the square block, the larger the allowable error; for the same specification: (\\boldsymbol{000 Grade &lt; 00 Grade &lt; 0 Grade}), accuracy decreases grade by grade.<br>Old Standard Supplement (Grade 1, small amount in circulation on the market)<br>Used only for ordinary workshop marking and rough inspection, tolerances are much larger than Grade 0, e.g., 200mm specification Grade 1 perpendicularity \u2264 8 \u03bcm.<br>Supporting Calibration Basis<br>Finished product factory inspection \/ periodic re-inspection follows: JJG 117-2013 Calibration Regulation for Surface Plates.<br>Quick Selection Reference<br>000 Grade: Metrology rooms, value transfer, standard instrument calibration<br>00 Grade: Precision machining quality inspection, CMM \/ vision system debugging, aerospace \/ mold high-precision inspection<br>0 Grade: Machining workshops, routine inspection, fitter&#8217;s 3D marking, workpiece alignment<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img alt=\"\" fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-1024x1024.jpg\" class=\"wp-image-1310\" srcset=\"https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-1024x1024.jpg 1024w, https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-300x300.jpg 300w, https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-150x150.jpg 150w, https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-768x768.jpg 768w, https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-12x12.jpg 12w, https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-800x800.jpg 800w, https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-100x100.jpg 100w, https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11.jpg 1126w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>","protected":false},"excerpt":{"rendered":"<p>I. Executive StandardsManufacturing Standard: JB\/T 10027-2017 &#8220;Granite Surface Plates, Straight Edges, Squares, and Square Boxes&#8221;Verification Standard: JJG 117-2013 &#8220;Verification Regulation for Surface Plates&#8221;Accuracy Grade: Grade 000, Grade 00, Grade 0 (the smaller the number, the higher the accuracy); some scenarios still use the old standard Grade 1 (General Industrial Grade). II. Grade Definitions and ApplicationsGrade&#8230;<\/p>","protected":false},"author":1,"featured_media":1310,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_analysis_target_kw":"","_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"categories":[35],"tags":[],"class_list":["post-2943","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"taxonomy_info":{"category":[{"value":35,"label":"NEWS"}]},"featured_image_src_large":["https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/01\/\u65b9\u7bb16-11-1024x1024.jpg",1024,1024,true],"author_info":{"display_name":"jinxing6611@gmail.com","author_link":"https:\/\/jtlcnc.com\/ru\/author\/jtlcnc\/"},"comment_info":0,"category_info":[{"term_id":35,"name":"NEWS","slug":"news","term_group":0,"term_taxonomy_id":35,"taxonomy":"category","description":"","parent":0,"count":254,"filter":"raw","cat_ID":35,"category_count":254,"category_description":"","cat_name":"NEWS","category_nicename":"news","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/posts\/2943","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/comments?post=2943"}],"version-history":[{"count":1,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/posts\/2943\/revisions"}],"predecessor-version":[{"id":2944,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/posts\/2943\/revisions\/2944"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/media\/1310"}],"wp:attachment":[{"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/media?parent=2943"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/categories?post=2943"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/tags?post=2943"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}