ASTM_D_4705_-_18.pdf

Designation:D470518Standard Test Method forStitch Tear Strength of Leather,Double Hole1This standard is issued under the fixed designation D4705;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript 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.Scope1.1 This test method is intended for use in determining thestitch tearing resistance of leather using a double hole tear.It isparticularly applicable to lightweight leathers.This test methoddoes not apply to wet blue.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1610 Practice for Conditioning Leather and Leather Prod-ucts for TestingD1813 Test Method for Measuring Thickness of LeatherTest SpecimensD2209 Test Method for Tensile Strength of LeatherD2813 Practice for Sampling Leather for Physical andChemical Tests3.Significance and Use3.1 This test method is designed to measure the loadrequired to tear leather through two holes in the test specimen.Tanners and leather buyers have found that this test gives anindication of the resistance of leather to tearing.It is ofparticular value in estimating the durability of leather towithstand tearing stresses encountered in the manufacture ofshoes,garments,and upholstered products.The thickness ofthe specimen and direction of tear relative to the backbone willaffect the uniformity of the test results.This test method maynot apply when the conditions of the test employed differwidely from those specified in the test method.4.Apparatus4.1 Testing Machine,as described in Test Method D2209.4.2 Thickness Gage,a dead weight type of thickness gage asdescribed in Method D1813.4.3 Steel Die,to cut test specimens(as described in 5.1).4.4 Paper Clip,Smooth,with wire diameter 0.041 6 0.002in.(1.04 6 0.05 mm).5.Sampling Test Specimen5.1 Unless otherwise specified,sample the leather accordingto Practice D2813.5.2 The specimen shall be a rectangle of leather 2 in.(50.8mm)in length and 1 in.(25.4 mm)in width with two holes(564in.(1.98 mm)in diameter on one end of the specimen.Thecenters of the holes shall be14in.(6.35 mm)from the end,14in.(6.35 mm)apart,and located equidistant from the centerline(length wise)of the specimen.See Fig.1.5.3 The specimen shall be cut with the long dimensionperpendicular to the backbone.6.Conditioning6.1 All specimen shall be conditioned and tested in anatmosphere as described in Practice D1610.7.Procedure7.1 Determine the thickness of the specimen to the nearest0.001 in.(0.01 mm)on the long axis near one end.7.2 Bend the wire into a“U”shape,preferably by bendingover a14in.(6.35 mm)rod,and pass the ends through the holesin the specimen so that both ends project from the flesh side of1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.07 on Physical Properties.Current edition approved Oct.1,2018.Published October 2018.Originallyapproved in 1987.Last previous edition approved in 2013 as D4705-13.DOI:10.1520/D4705-18.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 the specimen.Clamp both ends of the wire in the testingmachine grip,the jaws of which have been covered.Clamp thefree end of the specimen in the other grip of the testingmachine.7.3 Operate the machine at 10 6 2 in.(254 6 50.8 mm)perminute until the specimen tears.At the instant that thespecimen