{"id":2790,"date":"2026-05-22T08:37:16","date_gmt":"2026-05-22T00:37:16","guid":{"rendered":"https:\/\/jtlcnc.com\/?p=2790"},"modified":"2026-05-22T08:37:17","modified_gmt":"2026-05-22T00:37:17","slug":"how-are-the-accuracy-grades-of-granite-precision-gauges-classified","status":"publish","type":"post","link":"https:\/\/jtlcnc.com\/ru\/2026\/05\/22\/how-are-the-accuracy-grades-of-granite-precision-gauges-classified\/","title":{"rendered":"How are the accuracy grades of granite precision gauges classified?"},"content":{"rendered":"

Accuracy Grade Classification of Granite Precision Gauges (Surface Plates \/ Platforms)
Domestically, the mainstream standard is GB\/T 20428-2021 “Rock Surface Plates”, while internationally, ISO 8512-2 and DIN 876 are commonly used. The core classification is based on flatness tolerance, distinguishing grades 000, 00, 0, 1, and 2, with accuracy decreasing from high to low.
I. National Standard GB\/T 20428-2021 Grades (Most Commonly Used)<\/p>\n\n\n\n

    \n
  1. Accuracy Grades (from high to low)
    Grade 000 \u2192 Grade 00 \u2192 Grade 0 \u2192 Grade 1 \u2192 Grade 2
    Grade 000, Grade 00: Ultra-precision grade, used for CMM bases, laboratory references, and metrology room standard surface plates
    Grade 0: Precision inspection, laboratories, and high-precision machine tool accessories
    Grade 1: Workshop precision inspection, scribing, and tooling verification
    Grade 2: Ordinary workshop scribing, assembly, and fitter platforms<\/li>\n\n\n\n
  2. Core Rules for Flatness Tolerance (Unit: \u03bcm, taking 600\u00d7400mm as an example)
    Grade 000: Flatness \u2248 1.47\u03bcm
    Grade 00: \u2248 2.94\u03bcm
    Grade 0: \u2248 5.88\u03bcm
    Grade 1: \u2248 11.76\u03bcm
    Grade 2: \u2248 23.52\u03bcm
    Formula: Flatness Tolerance = Coefficient \u00d7 \u221a(Length \u00d7 Width)
    Coefficients: 000=0.003; 00=0.006; 0=0.012; 1=0.024; 2=0.048
    II. International Standard Comparison
    ISO 8512-2: Corresponds to grades 00, 0, 1, and 2, basically consistent with the national standard
    German DIN 876:
    Grade 00 (Ultra-precision), Grade 0 (Precision), Grade 1 (Normal)
    US ASME B89.3.7: Grades AA, A, B, and C, where AA \u2248 Grade 000, A \u2248 Grade 00
    III. Reference for Selecting Granite Gauge Grades
    Grade 000 \/ 00: CMMs, vision system bases, metrology institute standards, ultra-precision laboratories
    Grade 0: Precision machining workshop inspection, gauge verification, high-precision tooling
    Grade 1: Regular precision inspection, scribing, mold inspection
    Grade 2: Ordinary assembly, fitting, welding tooling
    IV. Key Supplements
    The larger the accuracy grade number, the larger the tolerance and the lower the accuracy; Grade 000 is the highest, and Grade 2 is the lowest.
    Granite materials such as Jinan Green, Zhangqiu Black, and Indian stone are preferred. Only materials with uniform density and good thermal stability can stably achieve Grade 000\/00.
    In addition to flatness, high-precision gauges will also specify: parallelism, perpendicularity, surface roughness, and linear expansion coefficient.<\/li>\n<\/ol>\n\n\n\n
    \"\"<\/figure>","protected":false},"excerpt":{"rendered":"

    Accuracy Grade Classification of Granite Precision Gauges (Surface Plates \/ Platforms)Domestically, the mainstream standard is GB\/T 20428-2021 “Rock Surface Plates”, while internationally, ISO 8512-2 and DIN 876 are commonly used. The core classification is based on flatness tolerance, distinguishing grades 000, 00, 0, 1, and 2, with accuracy decreasing from high to low.I. National Standard…<\/p>","protected":false},"author":1,"featured_media":2791,"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-2790","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\/05\/\u5fae\u4fe1\u56fe\u7247_20260521091502_4_11.png",1008,718,false],"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":204,"filter":"raw","cat_ID":35,"category_count":204,"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\/2790","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=2790"}],"version-history":[{"count":1,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/posts\/2790\/revisions"}],"predecessor-version":[{"id":2792,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/posts\/2790\/revisions\/2792"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/media\/2791"}],"wp:attachment":[{"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/media?parent=2790"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/categories?post=2790"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jtlcnc.com\/ru\/wp-json\/wp\/v2\/tags?post=2790"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}