GB/T 197-2018 PDF English
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GB/T 197: Historical versions
| Standard ID | USD | BUY PDF | Delivery | Standard Title (Description) | Status |
| GB/T 197-2018 | 245 | Add to Cart | Auto, 9 seconds. | General purpose metric screw threads -- Tolerances | Valid |
| GB/T 197-2003 | 759 | Add to Cart | 4 days | General purpose metric screw threads – Tolerances | Obsolete |
| GB/T 197-1981 | 479 | Add to Cart | 4 days | General purpose screw threads--Tolerances and fits for diameter from 1 to 355mm | Obsolete |
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GB/T 197-2018: General purpose metric screw threads -- Tolerances
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT197-2018GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 21.040.10 J 04 Replacing GB/T 197-2003 General purpose metric screw threads - Tolerances (ISO 965-1.2013, ISO general purpose metric screw threads - Tolerances - Part 1.Principles and basic data, MOD) Issued on. MARCH 15, 2018 Implemented on. OCTOBER 01, 2018 Issued by. General Administration of Quality Supervision, Inspection and Quarantine of the PRC; Standardization Administration of the PRC.
Table of Contents
Foreword... 3 1 Scope... 5 2 Normative references... 5 3 Terms, definitions and symbols... 5 4 Tolerance system... 7 5 Tolerance positions... 7 6 Tolerance grades... 9 7 Lengths of engagement... 12 8 Recommended tolerance classes... 18 9 Tolerances of multiple-start threads... 20 10 Tolerance formulae... 20 11 Root contours... 23 12 Thread designation... 25 Annex A (Informative) Supplementary method for marking tolerance class of coated threads... 30 Bibliography... 32Foreword
"General purpose metric screw threads" has issued the following standards. - GB/T 192-2003 General purpose metric screw threads - Basic profile; - GB/T 193-2003 General purpose metric screw threads - General plan; - GB/T 196-2003 General purpose metric screw threads - Basic dimensions; - GB/T 197-2018 General purpose metric screw threads - Tolerances; - GB/T 2516-2003 General purpose metric screw threads - Limit deviations; - GB/T 9144-2003 General purpose metric screw threads - Preferable plan; - GB/T 9145-2003 General purpose metric screw threads - Limits of sizes for the screw threads of medium quality and preferable plan; - GB/T 15756-2008 General purpose metric screw threads - Limits of sizes. This Standard is the tolerance standard of "General purpose metric screw threads". This Standard is drafted in accordance with the rules given in GB/T 1.1-2009. This Standard replaces GB/T 197-2003 "General purpose metric screw threads - Tolerances". Compared with GB/T 197-2003, the main technical changes of this Standard are as follows. - ADD four kinds of external thread tolerance positions (a, b, c and d) (see Clause 5); - ADD tolerances of multiple-start threads (see Clause 9); - ADD the designation of coated threads (see 12.5 and Annex A); - ADD the content of tolerance system (see Clause 4). This Standard uses the redraft law to modify and adopt ISO 965-1.2013 "ISO general purpose metric screw threads - Tolerances - Part 1.Principles and basic data". The main technical differences between this Standard and ISO 965- 1.2013 and their reasons are as follows. - As for the normative references, this Standard has made adjustments with technical differences, to adapt to the technical conditions of China. The adjustments are mainly reflected in Clause 2 “Normative references”. The specific adjustments are as follows. Replace ISO 68-1 with GB/T 192, which modifies and adopts the international standard; Replace ISO 261 with GB/T 193, which modifies and adopts the international standard; Replace ISO 1502 with GB/T 3934, which modifies and adopts the international standard; Replace ISO 5048 with GB/T 14791, which is identical to the international standard. - This Standard adds the designation of coated threads; expands the applicable types of coated threads in the ISO standard; and avoids misunderstandings about coated thread designation (see 12.5 and Annex A). - Delete Figure 1 of the ISO standard. The knowledge of limit deviation and tolerance class has been popularized; there is no need to explain. This Standard also makes the following editorial changes. - Modify the standard name; - ADD an informative Annex A. This Standard was proposed by and shall be under the jurisdiction of National Technical Committee 108 on Thread of Standardization Administration of China (SAC/TC 108). Drafting organizations of this Standard. Qifeng Precision Industry Sci-Tech Corp., China Productivity Center for Machinery, Beijing Automotive Technology Center Co., Ltd., Zhejiang Mekol Tools Co., Ltd., Zhejiang Changhua Auto Parts Co., Ltd. Main drafters of this Standard. Chen Yuezhong, Li Xiaobin, Luan Jianxin, Chen Pengyu, Zhang Yiwei. The previous editions of the standard replaced by this Standard were released as follows. - GB/T 197-1963, GB/T 197-1981, GB/T 197-2003. General purpose metric screw threads - Tolerances1 Scope
This Standard specifies the tolerances and designations of general purpose metric screw threads. The basic profile and general plan of general purpose metric screw threads shall meet the requirements of GB/T 192 and GB/T 193, respectively.2 Normative references
The following documents are indispensable for the application of this document. For the dated references, only the editions with the dates indicated are applicable to this document. For the undated references, the latest edition (including all the amendments) are applicable to this document. GB/T 192 General purpose metric screw threads - Basic profile (GB/T 192- 2003, ISO 68-1.1998, MOD)3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in GB/T 14791 apply.4 Tolerance system
The tolerance system consists of tolerance grades and tolerance positions. The tolerance grades are expressed by number, such as 4, 6 and 8.The tolerance positions are expressed by letter, such as H, G, h and g.5 Tolerance positions
The following tolerance positions for internal and external threads are standardized.6 Tolerance grades
The tolerance grades for the following screw thread pitch and crest diameters are standardized.7 Lengths of engagement
The lengths of thread engagement are classified into three groups. short (S),8 Recommended tolerance classes
In order to reduce the number of gauges and tools, the tolerance classes should preferably be chosen from Tables 7 and 8.9 Tolerances of multiple-start threads
With the same pitch, the crest diameter tolerances for multiple-start threads are the same as for single-start threads.10 Tolerance formulae
In order to give a uniform series of tolerance values, the above-mentioned rounding principle is not completely followed. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
