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It summarizes major geometric tolerance symbols such as straightness, flatness, circularity, profile controls, parallelism, perpendicularity, position, concentricity, symmetry, runout, and total runout, plus practical guidance on when to apply each. It also highlights changes between ASME Y14.5-1994 and ASME Y14.5-2009, introducing new modifiers.",{"@graph":14,"@context":72},[15,34,55],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/template/","Template",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/template/presentations/","Presentations",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/template/gdt-reference-guide-a-quick-reference-for-geometric-dimensioning-and-tolerancing/573285/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/gdt-reference-guide-a-quick-reference-for-geometric-dimensioning-and-tolerancing/573285.png","ImageObject",442,249,{"name":42,"@type":43},"Blitz","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-18","2026-10-14",true,{"@type":52,"interactionType":53,"userInteractionCount":26},"InteractionCounter",{"@type":54},"ViewAction",{"@type":56,"mainEntity":57},"FAQPage",[58,64,68],{"name":59,"@type":60,"acceptedAnswer":61},"What is a feature control frame in GD&T and what does it represent?","Question",{"text":62,"@type":63},"A feature control frame is the rectangular box that contains a GD&T callout. It conveys geometric tolerance information, which is always total (not plus/minus) and may be centered or allowed to float within limits.","Answer",{"name":65,"@type":60,"acceptedAnswer":66},"How do datum reference letters work in a GD&T callout?",{"text":67,"@type":63},"Datum references are listed in a specific order to show relative importance: primary, secondary, and tertiary. The order does not have to be alphabetical, but it must follow precedence.",{"name":69,"@type":60,"acceptedAnswer":70},"What changed when moving from ASME Y14.5-1994 to ASME Y14.5-2009?",{"text":71,"@type":63},"The guide states that ASME Y14.5-2009 replaces the 1994 version and that the drawing should clarify which standard is imposed. It also calls out key new modifiers, including the independency modifier (I) and the unequal tolerance zone modifier (U).","https://schema.org",{"og:url":32,"og:type":74,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":76,"canonical":32},"index,follow",{"doc_id":78,"site_id":7},573285,1792360021,{"code":4,"msg":81,"data":82},"success",[83,87,92,97,102,107,112,117,122],{"id":84,"doc_module":22,"doc_module_name":25,"category_name":29,"show_sort_weight":85,"slug":86},11,90,"presentations",{"id":88,"doc_module":22,"doc_module_name":25,"category_name":89,"show_sort_weight":90,"slug":91},12,"Resumes",80,"resumes",{"id":93,"doc_module":22,"doc_module_name":25,"category_name":94,"show_sort_weight":95,"slug":96},14,"Invoices",70,"invoices",{"id":98,"doc_module":22,"doc_module_name":25,"category_name":99,"show_sort_weight":100,"slug":101},15,"Posters",60,"posters",{"id":103,"doc_module":22,"doc_module_name":25,"category_name":104,"show_sort_weight":105,"slug":106},16,"Social Media",50,"social-media",{"id":108,"doc_module":22,"doc_module_name":25,"category_name":109,"show_sort_weight":110,"slug":111},17,"Forms",40,"forms",{"id":113,"doc_module":22,"doc_module_name":25,"category_name":114,"show_sort_weight":115,"slug":116},18,"Letters",30,"letters",{"id":118,"doc_module":22,"doc_module_name":25,"category_name":119,"show_sort_weight":120,"slug":121},21,"Paper Templates",5,"papers-templates",{"id":123,"doc_module":22,"doc_module_name":25,"category_name":124,"show_sort_weight":4,"slug":125},158,"General","general-158",{"code":4,"msg":81,"data":127},{"doc_id":78,"user_id":128,"nickname":42,"user_avatar":129,"doc_module":22,"category_id":84,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":130,"file_id":131,"file_url":132,"file_type":133,"file_size":134,"view_count":26,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":26,"language":135,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":136,"faqs":137,"seo_title":138,"seo_description":12,"update_tm":139,"read_time":22},24464137899374,"https://us-avatar.wpscdn.com/davatar_3d24733baf745e90a7e4bdd5f77d97b2","GD&T REFERENCE GUIDE  \nNAME  \nSYMBOL  \nFOR SURFACE  \nOR F.O.S.?  \nTOLERANCE ZONE SHAPE (see below)  \nCAN USE MMCOR LMC MODIFIER?  \nDATUM REF?  \nCREATES VIRTUAL CONDITION?  \nForm controls  \nPro!le controls  \nOrientation controls  \nLocation controls  \nRunout controls  \nStraightness  \nFlatness  \nCircularity  \nCylindricity  \nPro!le of a Line  \nPro!le of a Surface  \nParallelism  \nPerpendicularity  \n~~ ~~ Angularity  \nPosition  \nConcentricity  \nSymmetry  \nCircular Runout  \nTotal Runout  \n\n| | Either | a, c | Yes, if a F.O.S. | Never | Yes, if on F.O.S. |\n| --- | --- | --- | --- | --- | --- |\n\n\n| | Either | b | Yes, if a F.O.S. | Never | Yes, if on F.O.S. |\n| --- | --- | --- | --- | --- | --- |\n\na = 2 parallel lines b = 2 parallel planes c = cylinder d = 2 coaxial circles  \ne = 2 coaxial cylinders f = 2 irregular line boundaries g = 2 irregular surface boundaries h = sphere  \nF.O.S. stands for “feature of size”(a pin, hole, slot, etc.)  \nHelpful things to remember:  \n*The datum reference(s) may use  \nMMB or LMB modifiers, if a F.O.S. datum † Exception: position applied to coaxial holes  \n**It is not a true \"virtual condition\" as defined in the standard, but it does create a \"worst-­case boundary\" that may be important for assembly or function.  \nThe current standard for GD&T is ASME Y14.5-­2009, from the American Society of Mechanical Engineers. It replaces the 1994 version.  \nThe rectangular box that contains a GD&T callout is known as the \"feature control frame. \"  \nA geometric tolerance shown in a feature control frame is always total, not plus/minus. Depending on how it is used, it may be centered around a fixed location, or it may float within a given size limit.  \nThe datum references (the letters at the end of a feature control frame) are given in a specific order to show the relative importance of each (primary, secondary, and tertiary) . They do not have to be in alphabetical order, but rather order of precedence.  \nThe modifier M is helpful for clearance fits. It allows the tolerance to increase as the size of the feature varies. It can also be used on datum references if there might be looseness or \"play\" on those datum features.  \nDatum features should be identified on physical items (surface, hole, pin, etc.) not on an imaginary center line. Even if the true datum might be a center, the symbol should still appear on the feature from which the center is derived.  \nBasic dimensions (boxed dimensions) do not have any direct tolerance. Instead, they establish a perfect dimension, and then the GD&T takes over, in the form of a feature control frame. Basic dimensions are most common in conjunction with position and profile controls.  \nConcentricity is expensive to inspect. Often, position or runout can be used to achieve the same goal. (Reason: concentricity measures the centers of every cross-­section, but position measures the center of an envelope, and runout measures the physical surface.)  \nOne of the most powerful GD&T symbols is profile of a surface. It controls a shape (which is defined by basic dimensions) by building athree-­dimensional tolerance zone around it. And depending on how it relates to the datums, it can also control orientation and location.  \nModifiers:  \nM = max. mat’l condition/boundary L = least mat’l condition/boundary I = independency rule  \nF = free state P = projected tolerance zone U = unequal tolerance zone T = tangent plane  \n©[2012 Geometric Learning Systems www.gdtseminars.com](2012 Geometric Learning Systems www.gdtseminars.com)  \nChanges from the 1994 Y14.5 standard  \nThe standard for dimensioning and tolerancing was revised in 2009. ASME Y14.5-­2009 now replaces the 1994 version.  \nHowever, each company makes the decision as to when their new designs will begin to use the new standard. The title block or a general note should always be used to clarify which standard is being imposed on a given drawing.  \nThis page highlights the main changes that GD&T users need to be aware of. A more deta","cbCaib7xqwfwKOiv","https://ap.wps.com/l/cbCaib7xqwfwKOiv","pdf",233092,"English","# GD&T fundamentals\n## Feature control frames and datum references\n## MMC/LMC and datum feature identification\n# Geometric tolerance symbols\n## Form controls and profile controls\n## Orientation controls and location controls\n## Runout and total runout\n# Modifiers and updated standard\n## New modifiers and independency rule\n## Unequal tolerance zones (U)\n## All over/all around and continuous feature","[{\"question\":\"What is a feature control frame in GD\\u0026T and what does it represent?\",\"answer\":\"A feature control frame is the rectangular box that contains a GD\\u0026T callout. It conveys geometric tolerance information, which is always total (not plus/minus) and may be centered or allowed to float within limits.\"},{\"question\":\"How do datum reference letters work in a GD\\u0026T callout?\",\"answer\":\"Datum references are listed in a specific order to show relative importance: primary, secondary, and tertiary. The order does not have to be alphabetical, but it must follow precedence.\"},{\"question\":\"What changed when moving from ASME Y14.5-1994 to ASME Y14.5-2009?\",\"answer\":\"The guide states that ASME Y14.5-2009 replaces the 1994 version and that the drawing should clarify which standard is imposed. It also calls out key new modifiers, including the independency modifier (I) and the unequal tolerance zone modifier (U).\"}]","GD&T Reference Guide - A quick reference for geometric dimensioning and tolerancing | PDF",1791936596]