[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-573288-105":3,"detail-sidebar-cat-1-en-105":74,"doc-detail-573288-en":120},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":67,"head_meta":69,"extra_data":71,"updated_unix":73},105,"en","rules-and-concepts-of-gdt-rule-1","Rules and Concepts of GD&T - Rule #1","","Rules and Concepts of GD&T explains ASME Y14.5M-1994 default conditions for features of size, focusing on Rule #1, the “Individual Feature of Size Rule.” It describes how MMC and the envelope principle define both allowable size limits and associated form requirements, and how form error can emerge as a feature departs from MMC. The document also covers how to override Rule #1, its limitations and exceptions, and practical inspection using Go gages and No-Go gages for verifying size and Rule #1 form effects.",{"@graph":14,"@context":66},[15,34,49],{"@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/general/","General",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/template/rules-and-concepts-of-gdt-rule-1/573288/",4,{"url":32,"name":10,"@type":35,"author":36,"headline":10,"publisher":39,"fileFormat":42,"inLanguage":8,"description":12,"dateModified":43,"datePublished":43,"encodingFormat":42,"isAccessibleForFree":44,"interactionStatistic":45},"DigitalDocument",{"name":37,"@type":38},"Guten tag","Person",{"url":19,"name":40,"@type":41},"DocShare","Organization","application/pdf","2026-10-14",true,{"@type":46,"interactionType":47,"userInteractionCount":4},"InteractionCounter",{"@type":48},"ViewAction",{"@type":50,"mainEntity":51},"FAQPage",[52,58,62],{"name":53,"@type":54,"acceptedAnswer":55},"What does ASME Y14.5M-1994 Rule #1 establish for features of size?","Question",{"text":56,"@type":57},"Rule #1 establishes default conditions for an individual feature of size, using default envelopes tied to MMC and governing allowable form variation along with size limits.","Answer",{"name":59,"@type":54,"acceptedAnswer":60},"How do MMC and the envelope principle determine allowable form for Rule #1?",{"text":61,"@type":57},"When a feature is at MMC, it requires perfect form; as the feature departs from MMC, form error can be introduced up to the amount of departure, while still meeting the envelope principle.",{"name":63,"@type":54,"acceptedAnswer":64},"How can Rule #1 be overridden on a drawing and what does that change?",{"text":65,"@type":57},"Rule #1 can be overridden by applying a straightness control to the feature of size, or by adding a note such as “Perfect Form at MMC Not Required” next to the FOS dimension.","https://schema.org",{"og:url":32,"og:type":68,"og:title":10,"og:site_name":40,"og:description":12},"article",{"robots":70,"canonical":32},"index,follow",{"doc_id":72,"site_id":7},573288,1791936606,{"code":4,"msg":75,"data":76},"success",[77,82,87,92,97,102,107,112,117],{"id":78,"doc_module":22,"doc_module_name":25,"category_name":79,"show_sort_weight":80,"slug":81},11,"Presentations",90,"presentations",{"id":83,"doc_module":22,"doc_module_name":25,"category_name":84,"show_sort_weight":85,"slug":86},12,"Resumes",80,"resumes",{"id":88,"doc_module":22,"doc_module_name":25,"category_name":89,"show_sort_weight":90,"slug":91},14,"Invoices",70,"invoices",{"id":93,"doc_module":22,"doc_module_name":25,"category_name":94,"show_sort_weight":95,"slug":96},15,"Posters",60,"posters",{"id":98,"doc_module":22,"doc_module_name":25,"category_name":99,"show_sort_weight":100,"slug":101},16,"Social Media",50,"social-media",{"id":103,"doc_module":22,"doc_module_name":25,"category_name":104,"show_sort_weight":105,"slug":106},17,"Forms",40,"forms",{"id":108,"doc_module":22,"doc_module_name":25,"category_name":109,"show_sort_weight":110,"slug":111},18,"Letters",30,"letters",{"id":113,"doc_module":22,"doc_module_name":25,"category_name":114,"show_sort_weight":115,"slug":116},21,"Paper Templates",5,"papers-templates",{"id":118,"doc_module":22,"doc_module_name":25,"category_name":29,"show_sort_weight":4,"slug":119},158,"general-158",{"code":4,"msg":75,"data":121},{"doc_id":72,"user_id":122,"nickname":37,"user_avatar":123,"doc_module":22,"category_id":118,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":124,"file_id":125,"file_url":126,"file_type":127,"file_size":128,"view_count":4,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":129,"language":130,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":131,"faqs":132,"seo_title":133,"seo_description":12,"update_tm":73,"read_time":78},687212321768,"https://ap-avatar.wpscdn.com/avatar/a0010bdbe886d2fe77?x-image-process=image/resize,m_fixed,w_180,h_180&k=1789897067658708522","Alessandro Anzalone, Ph.D.  \nHillsborough Community College, Brandon Campus  \nSections:  \n1. Rules  \n2. Introduction to Basic Dimensions  \n3. Introduction to Virtual Condition and Boundary Conditions 4. Introduction to Bonus Tolerance  \nThere are two general rules in ASME Y14.5M-1994. The first rule establishes default conditions for features of size . The second rule establishes a default material condition for feature control frames .  \nRule \\#1  \nRule \\#1 is referred to as the “Individual Feature of Size Rule .” It is a key concept in geometric tolerancing. Rule \\#1 is a dimensioning rule used to ensure that features of size will assemble with one another . When Rule \\#1 applies, the maximum boundary (or envelope) for an external FOS is its MMC. The minimum envelope for an internal FOS is its MMC. To determine if two features of size will assemble, the designer can then compare the MMCs of the features of size .  \nRule \\#1: Where only a tolerance of size is specified, the limits of size of an individual feature prescribe the extent to which variations in its form—as well as in its size—are allowed.  \nIn industry, Rule \\#1 is often paraphrased as “perfect form at MMC” or the“envelope rule.”  \nThere are two components to Rule \\#1: the envelope principle and the effects on the form of a FOS as it departs from MMC. When Rule \\#1 applies, the limits of size define the size as well as the form of an individual FOS.  \nFor example, let’s look at how Rule \\#1 affects the diameter of a pin. When the pin diameter is at MMC, the pin must have perfect form . For a pin diameter, perfect form means perfect straightness and perfect roundness . This would allow the pin to fit through a boundary equal to its MMC. If the size of the pin was less than its MMC, the pin could contain form error (straightness and roundness error) equal to the amount the pin departed from MMC.  \nHow to Override Rule \\#1  \nRule \\#1 applies whenever a feature of size is specified on a drawing. There are two ways Rule \\#1 can be overridden:  \nIf a straightness control is applied to a feature of size, Rule \\#1 is  \noverridden.  \nIf a note such as “Perfect Form at MMC Not Required” is specified next toa FOS dimension, it exempts the FOS dimension from Rule \\#1 .  \nRule \\#1 Limitation  \nA part often contains multiple features of size. Rule \\#1 does not affect the location, orientation, or relationship between features of size. Features of size shown perpendicular, symmetrical, or coaxial must be controlled for location or orientation to avoid incomplete drawing specifications . Often, implied 90º angles are covered by a general angular tolerance note or by an angular tolerance in the drawing titleblock.  \nIn this figure there are four features of size, marked A, B, C, & D. Rule \\#1 applies independently to each FOS. The angles between these features of size (angles E, F, & G) are not controlled by Rule \\#1 .  \nExceptions to Rule \\#1  \nRule \\#1 does not apply to a FOS on a part subject to free-state variation in the unrestrained condition . In simple terms, Rule \\#1 does not apply to flexible parts that are not restrained.  \nRule \\#1 does not apply to stock sizes, such as bar stock, tubing, sheet metal, or structural shapes . Paragraph [2.7.1.3](2.7.1.3) in ASME Y14.5M-1994 explains why. It states,“. . . standards for these items govern the surfaces that remain in the as-furnished condition on the finished part.”  \nInspecting a Feature of Size  \nWhen inspecting a FOS that is controlled by Rule \\#1, both its size and form need to be verified.  \nThe MMC size and the Rule \\#1 envelope can be verified with a Go gage . AGo gage is a gage that is intended to fit into (for an internal FOS) or fit over (for an external FOS) the FOS. A Go gage is made to the MMC limit of the FOS and has perfect form . A Go gage can verify the MMC limit and Rule \\#1 form envelope of a FOS. To fully verify the Rule \\#1 effects, a Go gage must be at least as long as the FOS it is verifying.  \nThe mi","cbCaibnl1wULVGk2","https://ap.wps.com/l/cbCaibnl1wULVGk2","pdf",1385834,31,"English","# Sections\n## Rules\n## Introduction to Basic Dimensions\n## Introduction to Virtual Condition and Boundary Conditions\n## Introduction to Bonus Tolerance\n# Rule #1 Overview\n## Individual Feature of Size Rule\n## Envelope Principle and Form Effects\n## Example: Pin Diameter\n# How to Override Rule #1\n# Rule #1 Limitation\n# Exceptions to Rule #1\n# Inspecting a Feature of Size\n## Go gage verification\n## No-Go gage verification","[{\"question\":\"What does ASME Y14.5M-1994 Rule #1 establish for features of size?\",\"answer\":\"Rule #1 establishes default conditions for an individual feature of size, using default envelopes tied to MMC and governing allowable form variation along with size limits.\"},{\"question\":\"How do MMC and the envelope principle determine allowable form for Rule #1?\",\"answer\":\"When a feature is at MMC, it requires perfect form; as the feature departs from MMC, form error can be introduced up to the amount of departure, while still meeting the envelope principle.\"},{\"question\":\"How can Rule #1 be overridden on a drawing and what does that change?\",\"answer\":\"Rule #1 can be overridden by applying a straightness control to the feature of size, or by adding a note such as “Perfect Form at MMC Not Required” next to the FOS dimension.\"}]","Rules and Concepts of GD&T - Rule #1 | PDF"]