ASTM D2821-00(2005)e1
(Test Method)Standard Test Method for Measuring the Relative Stiffness of Leather by Means of a Torsional Wire Apparatus
Standard Test Method for Measuring the Relative Stiffness of Leather by Means of a Torsional Wire Apparatus
SIGNIFICANCE AND USE
This test method is designed to measure the apparent torsional modulus of a leather specimen. Experience has shown that the torsion modulus of leather is directly related to the characteristic known as stiffness when felt in a glove.5
SCOPE
1.1 This test method describes the use of a torsional apparatus for measuring the relative stiffness of gloving leathers. This test method does not apply to wet blue.
1.2 The values stated in SI units are to be regarded as the standard. The values shown in parentheses are provided for information only.
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
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Designation:D2821–00(Reapproved2005)
Standard Test Method for
Measuring the Relative Stiffness of Leather by Means of a
Torsional Wire Apparatus
This standard is issued under the fixed designation D2821; 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 Department of Defense.
´ NOTE—Adjunct references were corrected editorially in April 2006.
1. Scope Torsion apparatus (1 drawing)
1.1 This test method describes the use of a torsional
3. Significance and Use
apparatus for measuring the relative stiffness of gloving leath-
3.1 This test method is designed to measure the apparent
ers. This test method does not apply to wet blue.
torsionalmodulusofaleatherspecimen.Experiencehasshown
1.2 The values stated in SI units are to be regarded as the
that the torsion modulus of leather is directly related to the
standard. The values shown in parentheses are provided for
characteristic known as stiffness when felt in a glove.
information only.
1.3 This standard does not purport to address all of the
4. Apparatus
safety concerns, if any, associated with its use. It is the
4.1 Torsion Apparatus —The torsional apparatus, Fig. 1,
responsibility of the user of this standard to establish appro-
shall consist of a torsion head, A, capable of being turned
priate safety and health practices and determine the applica-
through a complete circle in a plane normal to the torsion wire.
bility of regulatory limitations prior to use.
The torsion head is equipped with an upper dial or protractor,
K, graduated from 0 to 360° in increments not greater than 5°,
2. Referenced Documents
and a fixed index pointer, L. The protractor is attached to the
2.1 ASTM Standards:
torsion head by means of a friction bearing to permit move-
D1053 Test Methods for Rubber Property—Stiffening at
ment for adjusting the zero point.The top of the torsion wire is
Low Temperatures: Flexible Polymers and Coated Fabrics
attached to the torsion head at knob H by set screw B and
D1610 Practice for Conditioning Leather and Leather Prod-
ucts for Testing
The method is similar to Test Method D1053. The original apparatus was
2.2 ASTM Adjuncts:
3 described by Williamson, I., British Plastics, Vol 23, 1950, pp. 87–90, 102; and
Standard torsion wire (2 pieces/set)
typical examples of the results of its use on leather were given in a paper by
Witnauer, L. PA, and Palm, W. E., Journal, American Leather Chemist’s Assn.,
JALCA, Vol 59, 1964, pp. 246–258. Working drawings for construction of the
This test method is under the jurisdiction ofASTM Committee D31 on Leather apparatus are available at nominal cost from ASTM International Headquarters.
and is the direct responsibility of Subcommittee D31.04 on Apparel. This test OrderAdjunctADJD282102. Original adjunct produced in 1985.There is no known
method was developed in cooperation with the American Leather Chemists Assn. source of supply of the equipment. The former producer, Fulton County Machine
Current edition approved April 4, 2006. Published September 2005. Originally and Supply Co., Inc. is no longer in business. If you are aware of alternative
approved in 1969 as D2821 – 69T. Last previous edition approved in 2000 as suppliers, please provide this information to ASTM Headquarters. Your comments
D2821 – 00. DOI: 10.1520/D2821-00R05E01. will receive careful consideration at a meeting of the responsible technical
For referenced ASTM standards, visit the ASTM website, www.astm.org, or committee, which you may attend.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Gloves were made from the neck and butt areas of cattlehide work-glove
Standards volume information, refer to the standard’s Document Summary page on leather selected for 3° of softness varying from soft to firm.These were ranked from
the ASTM website. softest to firmest by 20 individuals. Since there was some overlapping of rank as
Lengths of the standard wire can be obtained at nominal cost from ASTM assigned by individual observers, the final rank was assigned according to highest
International Headquarters. OrderAdjunctADJD282101. Original adjunct produced numberofselections.Specimensofleathercutfromthesidesintheareafromwhich
in 1975. A stainless steel rocket wire, Type NS-302, 0.010 6 0.0025 in. (0.025 6 each glove was cut were tested for stiffness according to this test method.At 90° of
0.06 mm) in diameter, bright finish, with chemical composition of 0.08 to 0.12 % twist, the stiffness values gave a ranking similar to that obtained by feel. Specimens
carbon, 8 to 10 % nickel, and 17 to 19 % chromium, available from National cut parallel to the backbone gave more consistant ranking than specimens cut
Standard Co., 1618-T Terminal Road, Niles, MI 49120; telephone: (616) 683-8100; perpendicular to the backbone. This undoubtedly reflects the fact that work gloves
fax: (616) 683-6249; has proved satisfactory. If other wire is used, it should be are cut from a side with the fingers parallel to the backbone. A report of these
calibrated as described in Test Method D1053 and have a constant of 0.0182 experiments and data used for calculation of precision and accuracy are on file at
g·cm/deg. ASTM Headquarters.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D2821–00 (2005)
6. Preparation of Apparatus
6.1 Clamp the specimen in the testing apparatus as de-
scribed below so that 89 6 2 mm (3.5 6 0.1 in.) of the
specimen is free between the clamps. It is advisable to mark
this distance on the specimen using a bench marker.
6.2 Insert the specimen into the jaws of the bottom clamp,
E, until the edge of the clamp meets the bench mark, and
tighten the two set screws using finger tip pressure. Be sure the
specimen is perpendicular to the jaws of the clamp.
6.3 Insert the other end of the specimen into the jaws of the
upper clamp, up to the bench mark and tighten the two set
screws using finger tip pressure. Be sure the specimen is
perpendicular to clamp.
6.4 Insert the bottom clamp into the clamp guide, F.
6.5 Unlock the top dial by turning knobG counterclockwise
about ⁄4 turn.
6.6 Bring both clamps into parallel position by turning knob
H, or knob M, either clockwise or counterclockwise so there is
no twist to the specimen. When the clamps are parallel adjust
the top clamp indicator, I, so it is over the “0” mark on the
lower dial, J, by holding the clamp parallel in one hand and
turning the indicator. The indicator is attached to the upper
clamp by a friction clasp.
FIG. 1 Torsion Apparatus
6.7 Lock the top dial, K, by turning knob G clockwise until
tight.
6.8 Set the top dial by actually turning dial K to read 270°
passes through the center of a loosely fitting sleeve gripped by (top dial is tension fitted).
the friction bearing. The torsion head support carries a split
NOTE 1—By setting the dial to 270°, the 90° twist of the specimen will
bearing which can be activa
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