ASTM_D_4831_-_00_2010.pdf

Designation:D483100(Reapproved 2010)Standard Test Method forBuckle Tear Strength of Leather1This standard is issued under the fixed designation D4831;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 Department of Defense.1.Scope1.1 This test method is intended for use on all types ofleather to determine the load required to tear a leather strapfastened in a buckle.This test method does not apply to wetblue.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Significance and Use2.1 This test method is designed to measure the loadrequired to tear a leather strap fastened in a buckle.Tanners andleather buyers have found that this test gives an indication ofthe resistance of leather to tearing.2.2 This test method should be suitable for specificationacceptance,designpurposes,manufacturingcontrol,development,and research.The thickness of the specimen anddirection of tear relative to the backbone will affect theuniformity of the test results.This test method may not applywhen the conditions of the test employed differ widely fromthose specified in this test method.3.Apparatus3.1 Gage,spring-type,for measuring thickness of units,graduated in 0.5 oz or 0.1 mm having a flat pressure foot 0.4 60.025 in.(10.2 6 0.6 mm)in diameter and a flat anvil 0.4 60.025 in.in diameter.The spring shall exert a force of 1 lbf(4.45 N)on the foot when the gage reads 2 oz and 2 lbf(8.9 N)when the gage reads 12 oz.3.2 Steel Punch,which will make a316in.(4.8 mm)diameter hole.3.3 Harness Buckle,1.25 in.(4.7 mm)with a 0.175 60.005-in.(4.4 6 0.1-mm)diameter tongue.It shall be attachedto a strong strap,1.25 in.wide and at least 5 in.(127 mm)long.The strap shall be equipped with a keeper located approxi-mately 0.75 in.(19 mm)from the buckle.3.4 Testing Machine,power-driven.The applied load shallbe indicated on a dial,scale,or chart.The load indicator shallrecord or indicate the maximum load at the time of rupture ofthe specimen.The machine shall be equipped with a set ofgrips for clamping the specimens.The faces of the grips shouldbe knurled or otherwise roughened to prevent slipping of thespecimen.The gripping surfaces shall be at least 1 by 112in.(25.4 by 38 mm).The grips shall be mounted with the longerdimension perpendicular to the direction of the application ofthe load.The speed of the power-activated grip shall be auniform speed of 10 6 2 in.(254 6 50 mm)/min when runningfree.The error of the machine up to a load of 50 lbf(222 N)shall not exceed 2%;at loads of more than 50 lbf the errorshall not exceed 1%.4.Sampling,Test Specimens,and Test Units4.1 The specimen shall be a piece of leather 1 by 8 in.(25by 200 mm).Note the direction of the long axis relative to thebackbone.5.Procedure5.1 Punch a316-in.(4.76-mm)hole on the long axis of thespecimen 3 in.(76.2 mm)from one end.5.2 Measure the thickness of the specimen to the nearest 0.5oz(0.2 mm)of the long axis between the hole and the shortend.Place the gage foot adjacent to,but not overlapping,thehole.5.3 Fit the specimen in the buckle with the tongue of thebuckle in the hole and the short end of the specimen under thekeeper.Clamp the other end of the specimen in one of thetesting machine grips so that the hole is approximately 3 in.(76mm)from the grip.Clamp the free end of the buckle strap inthe other grip.Operate the machine at 10 6 2 in.(254 6 501This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 on Vegetable LeatherCurrent edition approved April 1,2010.Published May 2010.Originallyapproved in 1988.Last previous edition approved in 2005 as D4831 00(2005).DOI:10.1520/D4831-00R10.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 mm)/min until the specimen begins to tear.At that instant,noteand record the load registered by the machine.6.Report6.1 The report shall include the following:6.1.1 The thickness of the sample which shall be the averageof the thickness measurements of the specimens,reported tothe nearest 0.5 oz(0.2 mm),6.1.2 The buckle tear strength of the sample which shall bethe average of the loads for the specimens,reported to thenearest 1 lb(0.45 kg),and6.1.3 The direction of the long axis relative to t