ASTM D2821-14
(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
3.1 This test method is designed to measure the apparent torsional modulus3 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.4
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 concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D2821 − 14
Standard Test Method for
Measuring the Relative Stiffness of Leather by Means of a
1
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 U.S. Department of Defense.
1. Scope shown that the torsion modulus of leather is directly related to
4
the characteristic known as stiffness when felt in a glove.
1.1 This test method describes the use of a torsional
apparatus for measuring the relative stiffness of gloving leath-
4. Apparatus
ers. This test method does not apply to wet blue.
5
4.1 Torsion Apparatus — The torsional apparatus, Fig. 1,
1.2 The values stated in SI units are to be regarded as the
shall consist of a torsion head, A, capable of being turned
standard. The values shown in parentheses are provided for
through a complete circle in a plane normal to the torsion wire,
information only.
N. The torsion head is equipped with an upper dial or
1.3 This standard does not purport to address all of the
protractor, K, graduated from 0 to 360° in increments not
safety concerns, if any, associated with its use. It is the
greater than 5°, and a fixed index pointer, L. The protractor is
responsibility of the user of this standard to establish appro-
attached to the torsion head by means of a friction bearing to
priate safety and health practices and determine the applica-
permit movement for adjusting the zero point. The top of the
bility of regulatory limitations prior to use.
torsion wire is attached to the torsion head at knob H by set
screwBandpassesthroughthecenterofalooselyfittingsleeve
2. Referenced Documents
gripped by the friction bearing. The torsion head support
2
2.1 ASTM Standards:
carries a split bearing which can be activated by knob G, thus
D1053 Test Methods for Rubber Property—Stiffening at
locking the sleeve carrying the wire and permitting adjustment
LowTemperatures: Flexible Polymers and Coated Fabrics
of the zero point of the protractor without disturbing the
D1610 Practice for Conditioning Leather and Leather Prod-
position of the torsion wire. The bottom of the wire shall be
ucts for Testing
fastenedtothetestspecimenclamp,C,bymeansofasetscrew
connector, D.Apointer, I, mounted above a fixed dial, J, shall
3. Significance and Use
3.1 This test method is designed to measure the apparent
3
torsional modulus of a leather specimen. Experience has
4
Gloves were made from the neck and butt areas of cattlehide work-glove
leather selected for 3° of softness varying from soft to firm.These were ranked from
1
This test method is under the jurisdiction ofASTM Committee D31 on Leather softest to firmest by 20 individuals. Since there was some overlapping of rank as
and is the direct responsibility of Subcommittee D31.04 on Apparel. This test assigned by individual observers, the final rank was assigned according to highest
method was developed in cooperation with the American Leather Chemists Assn. numberofselections.Specimensofleathercutfromthesidesintheareafromwhich
Current edition approved April 1, 2014. Published May 2014. Originally each glove was cut were tested for stiffness according to this test method.At 90° of
approved in 1969 as D2821 – 69T. Last previous edition approved in 2009 as twist, the stiffness values gave a ranking similar to that obtained by feel. Specimens
D2821 – 09. DOI: 10.1520/D2821-14. cut parallel to the backbone gave more consistent ranking than specimens cut
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or perpendicular to the backbone. This undoubtedly reflects the fact that work gloves
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM are cut from a side with the fingers parallel to the backbone. A report of these
Standards volume information, refer to the standard’s Document Summary page on experiments and data used for calculation of precision and accuracy are on file at
the ASTM website. ASTM Headquarters.
3 5
This test method is similar to Test Method D1053. The original apparatus was The sole source of supply of the apparatus known to the committee at this time
described by Williamson, I., British Plastics, Vol 23, 1950, pp 87-90, 102; and is Taber Industries, 455 Bryant Street, North Tonawanda, NY, 14120. If you are
typical examples of the results of its use on leather were given in a paper by aware of alternative suppliers, please provide this information to ASTM Interna-
Witnauer, L. PA, and Palm, W.E., Journal, American Leather Chemist’s Assn., tional H
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2821 − 09 D2821 − 14
Standard Test Method for
Measuring the Relative Stiffness of Leather by Means of a
1
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 U.S. Department of Defense.
1. 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 concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
D1053 Test Methods for Rubber Property—Stiffening at Low Temperatures: Flexible Polymers and Coated Fabrics
D1610 Practice for Conditioning Leather and Leather Products for Testing
3. Significance and Use
3
3.1 This test method is designed to measure the apparent torsional modulus of a leather specimen. Experience has shown that
4
the torsion modulus of leather is directly related to the characteristic known as stiffness when felt in a glove.
4. Apparatus
5
4.1 Torsion Apparatus — The torsional apparatus, Fig. 1, shall consist of a torsion head, A, capable of being turned through a
complete circle in a plane normal to the torsion wire, N. The torsion head is equipped with an upper dial or protractor, K, graduated
from 0 to 360° in increments not greater than 5°, and a fixed index pointer, L. The protractor is attached to the torsion head by
means of a friction bearing to permit movement for adjusting the zero point. The top of the torsion wire is attached to the torsion
head at knob H by set screw B and passes through the center of a loosely fitting sleeve gripped by the friction bearing. The torsion
head support carries a split bearing which can be activated by knob G, thus locking the sleeve carrying the wire and permitting
1
This test method is under the jurisdiction of ASTM Committee D31 on Leather and is the direct responsibility of Subcommittee D31.04 on Apparel. This test method
was developed in cooperation with the American Leather Chemists Assn.
Current edition approved Oct. 1, 2009April 1, 2014. Published December 2009May 2014. Originally approved in 1969 as D2821 – 69T. Last previous edition approved
ε1
in 20052009 as D2821 – 00D2821 – 09.(2005) . DOI: 10.1520/D2821-09.10.1520/D2821-14.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
This test method is similar to Test Method D1053. The original apparatus was described by Williamson, I., British Plastics, Vol 23, 1950, pp 87-90, 102; and 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.
4
Gloves were made from the neck and butt areas of cattlehide work-glove leather selected for 3° of softness varying from soft to firm. These were ranked from softest
to firmest by 20 individuals. Since there was some overlapping of rank as assigned by individual observers, the final rank was assigned according to highest number of
selections. Specimens of leather cut from the sides in the area from which each glove was cut were tested for stiffness according to this test method. At 90° of twist, the stiffness
values gave a ranking similar to that obtained by feel. Specimens cut parallel to the backbone gave more consistent ranking than specimens cut perpendicular to the backbone.
This undoubtedly reflects the fact that work gloves are cut from a side with the fingers parallel to the backbone. A report of these experiments and data used for calculation
of precision and accuracy are on file at ASTM Headquarters.
5
The sole source of supply of the apparatus known to the committee at this time is
...
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