Overview
ISO 2857:1973/Amd 1:1984 is an international standard published by the International Organization for Standardization (ISO). This amendment applies to ground thread taps for ISO metric threads, specifically those within tolerances 4H to 8H and 4G to 6G, covering both coarse and fine pitches. The amendment focuses on updating manufacturing tolerances on the threaded portion of these tools, with a central emphasis on the tolerances of the half-angle (a/2) of the thread.
This standard ensures that the dimensional accuracy and performance of ground thread taps meet rigorous international requirements, which is vital for reliable thread cutting and assembly in mechanical engineering and manufacturing sectors.
Key Topics
- Dimensional Tolerances: The amendment details the permissible variances for key thread dimensions, especially the half-angle (a/2).
- ISO Metric Threads: Applies to metric threading systems, the global standard for engineering threads.
- Taps for Coarse and Fine Pitches: The scope encompasses a wide range of thread pitch types, addressing diverse industrial applications.
- Tolerance Classes: Covers tolerance classes 4H to 8H and 4G to 6G, providing flexibility for different fit and strength requirements.
- Standardized Measurement: Implements updated table values for practical and consistent measurement of tap threads.
Applications
ISO 2857:1973/Amd 1:1984 serves various industries requiring precise, reliable threaded connections, including:
- Machinery Manufacturing: Ensures compatibility and interchangeability of threaded components across global supply chains.
- Automotive and Aerospace: Guarantees high-quality threads necessary for safety-critical and load-bearing applications.
- Toolmaking: Provides guidelines for manufacturers producing ground thread taps, ensuring uniformity and performance.
- Metalworking: Supports machinists and fabricators in achieving consistent thread profiles and tight tolerances, reducing errors and rework.
Practical value: By standardizing tap thread tolerances, this amendment helps reduce production variability, enhances component fit, and supports compliance with international engineering specifications. The updated tolerances also ensure the virtual pitch diameter error does not exceed established proportions of the pitch diameter tolerance for corresponding nut threads. This helps maintain function and longevity in threaded assemblies.
Related Standards
Professionals using ISO 2857:1973/Amd 1:1984 may also reference:
- ISO 965 - General tolerances for ISO metric screw threads
- ISO 529 - Technical requirements for metric thread taps
- ISO 2857:1973 - The base standard for manufacturing tolerances on ground thread taps
- ISO/TC 29 - Standards from the ISO Technical Committee for Small Tools
These related standards ensure comprehensive coverage for screw thread production, measurement, and quality assurance according to globally recognized ISO practices.
Keywords: ISO 2857:1973/Amd 1:1984, ground thread taps, ISO metric threads, thread tolerances, thread angle, manufacturing tolerances, metric thread taps, coarse pitch, fine pitch, tool standards, engineering threads, ISO standards.
Open preview (PDF)Ground thread taps for ISO metric threads of tolerances 4H to 8H and 4G to 6G coarse and fine pitches — Manufacturing tolerances on the threaded portion — Amendment 1