ASTM D4786-00(2020)

Standard Test Method for Stitch Tear Strength, Single Hole

SIGNIFICANCE AND USE
3.1 This test method is intended to be used to rate leathers as to their stitch tear strengths.
SCOPE
1.1 This test method is intended for determining the stitch-tearing strength of leather with a tear originating from one hole. It is particularly applicable to heavy leather. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Nov-2020
• ICS: 59.080.30 - Textile fabrics
• Technical Committee: D31 - Leather
• Drafting Committee: D31.01 - Vegetable Leather

Relations

• Refers: ASTM D1813-13 - Standard Test Method for Measuring Thickness of Leather Test Specimens
• Effective Date: 01-May-2013
• Refers: ASTM D1813-00(2010) - Standard Test Method for Measuring Thickness of Leather Test Specimens
• Effective Date: 01-Oct-2010
• Refers: ASTM D2209-00(2010) - Standard Test Method for Tensile Strength of Leather
• Effective Date: 01-Apr-2010
• Refers: ASTM D1813-00(2005) - Standard Test Method for Measuring Thickness of Leather Test Specimens
• Effective Date: 01-Apr-2005
• Refers: ASTM D2209-00(2004) - Standard Test Method for Tensile Strength of Leather
• Effective Date: 01-Sep-2004
• Refers: ASTM D2209-00 - Standard Test Method for Tensile Strength of Leather
• Effective Date: 10-Sep-2000
• Refers: ASTM D1813-00 - Standard Test Method for Measuring Thickness of Leather Test Specimens
• Effective Date: 10-May-2000

Overview

ASTM D4786-00(2020), titled “Standard Test Method for Stitch Tear Strength, Single Hole,” is a standardized procedure developed by ASTM International for evaluating the stitch-tearing strength of leather materials. This test method is specifically designed to measure the resistance of heavy leather to tearing that begins from a single hole, offering crucial insights into the durability and suitability of leather products for various applications. ASTM D4786 is widely recognized in the leather industry and by the U.S. Department of Defense, ensuring consistent quality assessment of leather goods.

Key Topics

• Stitch Tear Strength: The method focuses on measuring the force required to initiate a tear in leather at the site of a punched single hole, commonly found at points of stitching. This ensures that finished leather products meet specific strength requirements relevant to their end use.
• Applicability: The standard is particularly applicable to heavy leathers, excluding wet blue materials.
• Test Procedure: The test utilizes a standardized specimen size, specific punching tools, and a tensile testing machine to apply controlled force until tearing begins.
• Measurement and Reporting: Data collected includes the force at initial tear, specimen thickness, and the direction relative to the leather’s backbone, ensuring comparability across tests.
• Units of Measurement: Results are reported in inch-pound units, the accepted standard for this method.

Applications

ASTM D4786-00(2020) plays a critical role in the leather industry, ensuring product quality and performance across various sectors. Its key applications include:

• Quality Control: Manufacturers of leather goods such as belts, footwear, luggage, saddles, and upholstery use this standard to verify the strength and durability of their products, especially where stitching is involved.
• Product Development: Research and development teams utilize stitch tear strength data to select appropriate leather grades, modify product designs, and ensure long-lasting, high-quality goods.
• Compliance and Procurement: The test method is often specified in procurement contracts and by regulatory bodies, ensuring consistent material performance for products delivered to the U.S. Department of Defense or other quality-focused sectors.
• Failure Analysis: When a product fails, stitch tear strength testing can help determine whether leather quality or stitching techniques contributed to the issue.

Related Standards

ASTM D4786 is part of a broader family of standards that address leather testing and material performance:

• ASTM D1813: Standard Test Method for Measuring Thickness of Leather Test Specimens – referenced for specimen thickness measurement in D4786.
• ASTM D2209: Standard Test Method for Tensile Strength of Leather – referenced for test equipment and procedural consistency.
• International Standards: Developed in alignment with globally recognized principles set by the World Trade Organization Technical Barriers to Trade (TBT) Committee, supporting international trade and standardization efforts.

Keywords: leather, stitch tear strength, tear resistance, ASTM D4786, heavy leather testing, leather quality standards, leather durability, compliance, tensile strength, thickness measurement, material testing, quality assurance.

By adhering to ASTM D4786-00(2020), manufacturers and quality professionals can confidently assess stitch tear strength, ensuring that leather products meet rigorous industry and international standards for performance and durability.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4786 − 00 (Reapproved 2020)
Standard Test Method for
Stitch Tear Strength, Single Hole
This standard is issued under the fixed designation D4786; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 4.2 Steel Punch, beveled on the outside, which will make a
⁄8 in. diameter hole.
1.1 This test method is intended for determining the stitch-
tearing strength of leather with a tear originating from one
4.3 Metal Yoke, made to the dimension shown in Fig. 1.
hole. It is particularly applicable to heavy leather. This test
4.4 Steel Rod, 0.095 6 0.005 in. in diameter and at least 1
method does not apply to wet blue.
in. long.
1.2 The values stated in inch-pound units are to be regarded
4.5 Testing Machine, power-driven, as described in Test
as standard. No other units of measurement are included in this
Method D2209.
standard.
1.3 This standard does not purport to address all of the
5. Test Specimen
safety concerns, if any, associated with its use. It is the
5.1 The test specimen shall be a rectangular piece of leather
responsibility of the user of this standard to establish appro-
1 in. by 2 in. die cut from the sample unit of leather. The end
priate safety, health, and environmental practices and deter-
of the specimen in which the hole is to be punched shall be at
mine the applicability of regulatory limitations prior to use.
least 1 in. away from any uncut edge on the unit. The direction
1.4 This international standard was developed in accor-
of the long axis relative to the backbone shall be noted.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
6. Procedure
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
6.1 Place the specimen on the anvil of the thickness gage
Barriers to Trade (TBT) Committee.
and lower the presser foot gently (do not drop) until it rests on
the specimen.Take the reading 5 s after the full load is reached.
2. Referenced Documents
Read the thickness to the nearest 0.001 in. The thickness of the
2.1 ASTM Standards:
specimen should be taken on the long axis near the end in
D1813 Test Method for Measuring Thickness of Leather
which the hole is to be punched.
Test Specimens
6.2 Punch a ⁄8 in. diameter hole on the long axis of the
D2209 Test Method for Tensile Strength of Leather
specimen. The center of the hole should be ⁄32 in. from the end
on which the thickness was measured.
3. Significance and Use
3.1 This test method is intended to be used to rate leathers
6.3 Grip the yoke in one of the testing machine jaws. Place
as to their stitch tear strengths.
the end of the specimen containing the hole between the arms
of the yoke and pass the steel rod through the holes in the yoke
4. Apparatus
and the specimen. Clamp the free end of the specimen in the
4.1 Thickness Gage—A dead-mass type of thickness gage, other testing machine grip. Operate the machine at 10 6 2 in.
as described in Test Method D1813.
...