ASTM D143-23

Standard Test Methods for Small Clear Specimens of Timber

SIGNIFICANCE AND USE
4.1 These test methods cover tests on small clear specimens of wood that are made to provide the following:  
4.1.1 Data for comparing the mechanical properties of various species,  
4.1.2 Data for the establishment of correct strength functions, which in conjunction with results of tests of timbers in structural sizes (see Test Methods D198 and Test Methods D4761), afford a basis for establishing allowable stresses, and  
4.1.3 Data to determine the influence on the mechanical properties of such factors as density, locality of growth, position in cross section, height of timber in the tree, change of properties with seasoning or treatment with chemicals, and change from sapwood to heartwood.
SCOPE
1.1 These test methods cover the determination of various strength and related properties of wood by testing small clear specimens.  
1.1.1 These test methods represent procedures for evaluating the different mechanical and physical properties, controlling factors such as specimen size, moisture content, temperature, and rate of loading.  
1.1.2 Sampling and collection of material is discussed in Practice D5536. Sample data, computation sheets, and cards have been incorporated, which were of assistance to the investigator in systematizing records.  
1.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. When a weight is prescribed, the basic inch-pound unit of weight (lbf) and the basic SI unit of mass (Kg) are cited.  
1.2 The procedures for the various tests appear in the following order:    
Sections  
Photographs of Specimens  
5  
Control of Moisture Content and Temperature  
6  
Record of Heartwood and Sapwood  
7  
Static Bending  
8  
Compression Parallel to Grain  
9  
Impact Bending  
10  
Toughness  
11  
Compression Perpendicular to Grain  
12  
Hardness  
13  
Shear Parallel to Grain  
14  
Cleavage  
15  
Tension Parallel to Grain  
16  
Tension Perpendicular to Grain  
17  
Nail Withdrawal  
18  
Specific Gravity and Shrinkage in Volume  
19  
Radial and Tangential Shrinkage  
20  
Moisture Determination  
21  
Permissible Variations  
22  
Calibration  
23  
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: 14-Nov-2023
• ICS: 79.040 - Wood, sawlogs and sawn timber
• Technical Committee: D07 - Wood
• Drafting Committee: D07.01 - Fundamental Test Methods and Properties

Relations

• Replaces: ASTM D143-22 - Standard Test Methods for Small Clear Specimens of Timber
• Effective Date: 15-Nov-2023
• Referred By: ASTM D5457-23 - Standard Specification for Computing Reference Resistance of Wood-Based Materials and Structural Connections for Load and Resistance Factor Design
• Effective Date: 15-Nov-2023
• Referred By: ASTM D7031-11(2019) - Standard Guide for Evaluating Mechanical and Physical Properties of Wood-Plastic Composite Products
• Effective Date: 15-Nov-2023
• Referred By: ASTM D1761-20 - Standard Test Methods for Mechanical Fasteners in Wood and Wood-Based Materials
• Effective Date: 15-Nov-2023
• Referred By: ASTM D1036-99(2017) - Standard Test Methods of Static Tests of Wood Poles
• Effective Date: 15-Nov-2023
• Referred By: ASTM D3983-98(2019) - Standard Test Method for Measuring Strength and Shear Modulus of Nonrigid Adhesives by the Thick-Adherend Tensile-Lap Specimen
• Effective Date: 15-Nov-2023
• Referred By: ASTM D3931-08(2023) - Standard Test Method for Determining Strength of Gap-Filling Adhesive Bonds in Shear by Compression Loading
• Effective Date: 15-Nov-2023
• Referred By: ASTM D245-22 - Standard Practice for Establishing Structural Grades and Related Allowable Properties for Visually Graded Lumber
• Effective Date: 15-Nov-2023
• Referred By: ASTM D4680-98(2023) - Standard Test Method for Creep and Time to Failure of Adhesives in Static Shear by Compression Loading (Wood-to-Wood)
• Effective Date: 15-Nov-2023
• Referred By: ASTM D2555-17a - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 15-Nov-2023
• Referred By: ASTM D3499-19 - Standard Test Method for Toughness of Wood Structural Panels
• Effective Date: 15-Nov-2023
• Referred By: ASTM D7199-20 - Standard Practice for Establishing Characteristic Values for Reinforced Glued Laminated Timber (Glulam) Beams Using Mechanics-Based Models
• Effective Date: 15-Nov-2023
• Referred By: ASTM D9-20 - Standard Terminology Relating to Wood and Wood-Based Products
• Effective Date: 15-Nov-2023
• Referred By: ASTM D6570-18a(2023)e1 - Standard Practice for Assigning Allowable Properties for Mechanically Graded Lumber
• Effective Date: 15-Nov-2023
• Referred By: ASTM D905-08(2021) - Standard Test Method for Strength Properties of Adhesive Bonds in Shear by Compression Loading
• Effective Date: 15-Nov-2023

Overview

ASTM D143-23, "Standard Test Methods for Small Clear Specimens of Timber," published by ASTM International, establishes standardized procedures for determining key mechanical and physical properties of wood through testing of small, clear, defect-free timber specimens. This standard is widely adopted for comparative evaluation of wood species and supports the development of reliable design values for structural applications. The tests are essential for assessing the intrinsic qualities of wood unaffected by growth flaws, knots, or other abnormalities, and are recognized internationally for their role in unifying timber property data.

Key Topics

• Testing Scope: Encompasses evaluation of mechanical properties such as static bending, compression (parallel and perpendicular to grain), impact bending, hardness, shear, cleavage, tension (parallel and perpendicular to grain), and nail withdrawal. Physical properties like specific gravity, shrinkage, and moisture content are also measured.
• Specimen Preparation: Focuses on small, clear wood specimens, with strict controls on size, moisture, and temperature to ensure repeatability and comparability. Both primary (2 in. by 2 in.) and secondary (1 in. by 1 in.) cross-sections are described, reflecting historical and practical constraints.
• Significance: Provides foundational data for comparing wood species, establishing strength functions, and factoring environmental or physical influences such as density, location of growth, and seasoning. Enables reliable design and safety calculations in timber structures when combined with results from larger structural-size timber tests.
• Measurement Practice: Includes detailed methods for recording and evaluating load-deformation curves, failure types, and specimen characteristics (e.g., heartwood vs. sapwood), ensuring comprehensive test data for wood characterization.
• Use of Accurate Equipment: Emphasizes the importance of calibrated, reliable measuring and testing apparatus, whether mechanical or electronic, to meet specified accuracy requirements.

Applications

ASTM D143-23 is vital for:

• Wood Species Classification: Used by forestry professionals, engineers, and researchers to compare mechanical and physical properties across diverse wood species under consistent testing protocols.
• Material Selection and Design: Supports manufacturers and designers in selecting wood species for structural, furniture, or specialty applications where specific strength and durability characteristics are required.
• Engineering Standards: Supplies critical data for establishing allowable design stresses and performance parameters, which feed into national and international building codes for wood construction.
• Quality Control and Research: Enables systematic quality assurance in forestry products and provides robust support for academic and industrial research on wood properties, effects of treatments, and environmental adaptation.
• Moisture and Growth Analysis: Examines influence of factors like moisture content, density, seasoning, and growth characteristics (sapwood/heartwood) on wood performance, aiding in resource management and grading.

Related Standards

The following ASTM standards and practices are frequently referenced alongside D143-23 for a comprehensive approach to wood and timber testing:

• ASTM D198 - Test Methods of Static Tests of Lumber in Structural Sizes
• ASTM D5536 - Practice for Sampling Forest Trees for Determination of Clear Wood Properties
• ASTM D2395 - Test Methods for Density and Specific Gravity of Wood and Wood-Based Materials
• ASTM D4761 - Test Methods for Mechanical Properties of Lumber and Wood-Based Structural Materials
• ASTM D3043 - Test Methods for Structural Panels in Flexure
• ASTM D4442 - Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
• ASTM E4 - Practices for Force Calibration and Verification of Testing Machines

ASTM D143-23 remains one of the most authoritative standards for clear wood specimen testing, forming a cornerstone for reliable, comparable, and internationally recognized timber property data used across multiple industries. Employing this standard enhances confidence in wood product performance and ensures alignment with global best practices in timber engineering and testing.

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: D143 − 23
Standard Test Methods for
Small Clear Specimens of Timber
This standard is issued under the fixed designation D143; 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.
INTRODUCTION
The need to classify wood species by evaluating the physical and mechanical properties of small
clear specimens has always existed. Because of the great variety of species, variability of the material,
continually changing conditions of supply, many factors affecting test results, and ease of comparing
variables, the need will undoubtedly continue to exist.
In the preparation of these methods for testing small clear specimens, consideration was given both
to the desirability of adopting test methods that would yield results comparable to those already
available and to the possibility of embodying such improvements as experience has shown desirable.
In view of the many thousands of tests made under a single comprehensive plan by the U.S. Forest
Service, the former Forest Products Laboratories of Canada (now FPInnovations), and other similar
organizations, these test methods naturally conform closely to the methods used by those institutions.
These test methods are the outgrowth of a study of both American and European experience and
methods. The general adoption of these test methods will tend toward a world-wide unification of
results, permitting an interchange and correlation of data, and establishing the basis for a cumulative
body of fundamental information on the timber species of the world. Many of the figures in this
standard use sample data and computation sheets from testing done in the 1950s and earlier. These
figures remain in the standard because they are still valid depictions of the recording and plotting of
test results and also provide a historical link to the large body of test data on small clear specimens
already in existence for this long-standing test method.
Descriptions of some of the strength tests refer to primary methods and secondary methods. Primary
methods provide for specimens of 2-in. by 2-in. (50 mm by 50 mm) cross section. This size of
specimen has been extensively used for the evaluation of various mechanical and physical properties
of different species of wood, and a large number of data based on this primary method have been
obtained and published.
The 2-in. by 2-in. (50 mm by 50 mm) size has the advantage in that it embraces a number of growth
rings, is less influenced by earlywood and latewood differences than smaller size specimens, and is
large enough to represent a considerable portion of the sampled material. It is advisable to use primary
method specimens wherever possible. There are circumstances, however, when it is difficult or
impossible to obtain clear specimens of 2-in. by 2-in. cross section having the required 30 in.
(760 mm) length for static bending tests. With the increasing incidence of smaller second growth trees,
and the desirability in certain situations to evaluate a material which is too small to provide a 2-in. by
2-in. cross section, a secondary method which utilizes a 1-in. by 1-in. (25 mm by 25 mm) cross section
has been included. This cross section is established for compression parallel to grain and static bending
tests, while the 2-in. by 2-in. cross section is retained for impact bending, compression perpendicular
to grain, hardness, shear parallel to grain, cleavage, and tension perpendicular to grain. Toughness and
tension parallel to grain are special tests using specimens of smaller cross section.
The user is cautioned that test results between two different sizes of specimens are not necessarily
directly comparable. Guidance on the effect of specimen size on a property being evaluated is beyond
the scope of these test methods and should be sought elsewhere.
Where the application, measurement, or recording of load and deflection can be accomplished using
electronic equipment and computerized apparatus, such devices are encouraged. It is important that all
data measurement and recording equipment, whether electronic or mechanical, be accurate and
reliable to the degree specified.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D143 − 23
1. Scope 2. Referenced Documents
1.1 These test methods cover the determination of various 2.1 ASTM Standards:
strength and related properties of wood by testing small clear D9 Terminology Relating to Wood and Wood-Based Prod-
specimens. ucts
1.1.1 These test methods represent procedures for evaluat- D198 Test Methods of Static Tests of Lumber in Structural
ing the different mechanical and physical properties, control- Sizes
ling factors such as specimen size, moisture content, D2395 Test Methods for Density and Specific Gravity (Rela-
temperature, and rate of loading. tive Density) of Wood and Wood-Based Materials
1.1.2 Sampling and collection of material is discussed in D3043 Test Methods for Structural Panels in Flexure
Practice D5536. Sample data, computation sheets, and cards D4442 Test Methods for Direct Moisture Content Measure-
have been incorporated, which were of assistance to the ment of Wood and Wood-Based Materials
investigator in systematizing records. D4761 Test Methods for Mechanical Properties of Lumber
1.1.3 The values stated in inch-pound units are to be and Wood-Based Structural Materials
regarded as the standard. The values given in parentheses are D5536 Practice for Sampling Forest Trees for Determination
mathematical conversions to SI units that are provided for of Clear Wood Properties
information only and are not considered standard. When a E4 Practices for Force Calibration and Verification of Test-
weight is prescribed, the basic inch-pound unit of weight (lbf) ing Machines
and the basic SI unit of mass (Kg) are cited. E2309 Practices for Verification of Displacement Measuring
Systems and Devices Used in Material Testing Machines
1.2 The procedures for the various tests appear in the
following order:
3. Summary of Test Methods
Sections
3.1 The mechanical tests are static bending, compression
Photographs of Specimens 5
Control of Moisture Content and Temperature 6 parallel to grain, impact bending toughness, compression
Record of Heartwood and Sapwood 7
perpendicular to grain, hardness, shear parallel to grain,
Static Bending 8
cleavage, tension parallel to grain, tension-perpendicular-to-
Compression Parallel to Grain 9
Impact Bending 10
grain, and nail-withdrawal tests. These tests are permitted for
Toughness 11
both green and air-dry material as specified in these test
Compression Perpendicular to Grain 12
methods. In addition, test methods for evaluating such physical
Hardness 13
Shear Parallel to Grain 14
properties as specific gravity, shrinkage in volume, radial
Cleavage 15
shrinkage, and tangential shrinkage are presented.
Tension Parallel to Grain 16
Tension Perpendicular to Grain 17
NOTE 1—The test for shearing strength perpendicular to the grain
Nail Withdrawal 18
(sometimes termed “vertical shear”) is not included as one of the principal
Specific Gravity and Shrinkage in Volume 19
mechanical tests since in such a test the strength is limited by the shearing
Radial and Tangential Shrinkage 20
resistance parallel to the grain.
Moisture Determination 21
Permissible Variations 22
4. Significance and Use
Calibration 23
1.3 This standard does not purport to address all of the
4.1 These test methods cover tests on small clear specimens
safety concerns, if any, associated with its use. It is the
of wood that are made to provide the following:
responsibility of the user of this standard to establish appro-
4.1.1 Data for comparing the mechanical properties of
priate safety, health, and environmental practices and deter-
various species,
mine the applicability of regulatory limitations prior to use.
4.1.2 Data for the establishment of correct strength
1.4 This international standard was developed in accor-
functions, which in conjunction with results of tests of timbers
dance with internationally recognized principles on standard-
in structural sizes (see Test Methods D198 and Test Methods
ization established in the Decision on Principles for the
D4761), afford a basis for establishing allowable stresses, and
Development of International Standards, Guides and Recom-
4.1.3 Data to determine the influence on the mechanical
mendations issued by the World Trade Organization Technical
properties of such factors as density, locality of growth,
Barriers to Trade (TBT) Committee.
position in cross section, height of timber in the tree, change of
properties with seasoning or treatment with chemicals, and
change from sapwood to heartwood.
These test methods are under the jurisdiction of ASTM Committee D07 on
Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental
Test Methods and Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 15, 2023. Published December 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1922. Last previous edition approved in 2022 as D143 – 22. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D0143-23. the ASTM website.
D143 − 23
FIG. 1 Cross Sections of Bending Specimens Showing Different Rates of Growth of Longleaf Pine (2-in. by 2-in. (50 mm by 50 mm)
Specimens)
FIG. 2 Tangential Surfaces of Bending Specimens of Different Rates of Growth of Jeffrey Pine 2-in. by 2-in. by 30-in. (50 mm by 50 mm
by 760 mm) Specimens
5. Photographs of Specimens 6.2 Moisture Content—Moisture content shall be managed
based on the objective of the test: Specimens for tests in the
5.1 Four of the static bending specimens from each species
green condition shall be stored and manipulated in such a
shall be selected for photographing, as follows: two average
manner that their moisture content remains above the fiber
growth, one fast growth, and one slow growth. These speci-
saturation point; specimens for in-situ tests shall be maintained
mens shall be photographed in cross section and on the radial
at the in-situ moisture content; and specimens for tests in the
and tangential surfaces. Fig. 1 is a typical photograph of a cross
air-dry condition shall be conditioned to approximately con-
section of 2-in. by 2-in. (50 mm by 50 mm) test specimens, and
stant weight before the test. Tests shall be carried out in such
Fig. 2 is the tangential surface of such specimens.
a manner that influential changes in moisture content do not
6. Control of Moisture Content and Temperature
occur during the tests.
6.1 In recognition of the significant influence of moisture
content and temperature on the physical and mechanical
properties of wood, these factors shall be controlled and
reported to ensure comparable test results.
NOTE 2—It is desirable that the testing room and the room for
preparation of test specimens are temperature- and humidity-controlled.
D143 − 23
3,4
NOTE 3—USDA Technical Bulletin 479 describes the sensitivity of
8.2 Loading Span and Supports—Use center loading and a
wood properties to moisture content changes. This reference may be
span length of 28 in. (710 mm) for the primary method and
useful when determining influential moisture content changes relative to
14 in. (360 mm) for the secondary method. These spans were
the wood properties being tested.
established in order to maintain a minimum span-to-depth ratio
6.3 Temperature—The temperature of the specimens shall
of 14. Both supporting knife edges shall be provided with
be 68 °F 6 6 °F (20 °C 6 3 °C) except when the effects of
bearing plates and rollers of such thickness that the distance
other temperatures are to be evaluated. The conditioning
from the point of support to the central plane is not greater than
temperature and the temperature at the time of test shall be
the depth of the specimen (Fig. 3). The knife edges shall be
recorded.
adjustable laterally to permit adjustment for slight twist in the
specimen.
NOTE 4—Temperature and relative humidity affect the equilibrium
moisture content and wood properties. Historically, when testing wood in
NOTE 5—An example of laterally adjustable supports is provided in
the air-dry condition, the equilibrium moisture content is based on
Figure 1 of Test Methods D3043.
hygrothermal conditioning at a temperature of 68 °F 6 6 °F (20 °C 6
3 °C) and 65 % 6 5 % relative humidity.
8.3 Bearing Block—A rigid bearing block having a radius of
3 in. (76 mm) and a chord length of not less than 3 ⁄16 in.
7. Record of Heartwood and Sapwood
(97 mm) that is fixed from rotation shall be used for applying
7.1 Proportion of Sapwood—If heartwood and sapwood
the load for primary method specimens. An example is
present in the specimen can be distinguished by visual
provided in Fig. 4. A similar block having a radius of 1 ⁄2 in.
inspection, the proportion of sapwood present shall be esti-
(38 mm) for a chord length of not less than 2 in. (50 mm) shall
mated as required for the purposes of the test program and
be used for secondary method specimens. The bearing block
recorded for each test specimen.
shall be fabricated with a material that will not appreciably
deform under load.
8. Static Bending
8.4 Placement of Growth Rings—The specimen shall be
8.1 Size of Specimens—The static bending tests shall be
placed so that the load will be applied through the bearing
made on 2 in. by 2 in. by 30 in. (50 mm by 50 mm by 760 mm)
block to the tangential surface nearest the pith.
primary method specimens or 1 in. by 1 in. by 16 in. (25 mm
by 25 mm by 410 mm) secondary method specimens. The
8.5 Speed of Testing—The load shall be applied continu-
actual height and width at the center and the length shall be
ously throughout the test at a rate of motion of the movable
measured (see 22.2).
crosshead of 0.10 in. (2.5 mm)/min, for primary method
specimens, and at a rate of 0.05 in. (1.3 mm)/min for secondary
method specimens (see 22.3).
Markwardt, L.J. and T.R.J. Wilson. 1935. Strength and related properties of
8.6 Load-Deflection Curves:
woods grown in the United States.Technical Bulletin No. 479. Forest Products
Laboratory, USDA, Washington, DC. 8.6.1 At a minimum, the load-deflection curves shall be
Available from USDA National Agricultural Library Digital Collections
recorded and the test continued up to the maximum load for all
(https://naldc.nal.usda.gov).
FIG. 3 Static Bending Test Assembly Showing Test Method of Load Application, Specimen Supported on Rollers and Laterally Adjust-
able Knife Edges, and Test Method of Measuring Deflection at Neutral Axis by Means of Yoke and Displacement Measurement Device
D143 − 23
increments. When data are recorded electronically, the data
recording rate shall be sufficient to capture the same points so
that they can be similarly reported.
NOTE 7—See Fig. 5 for a sample static bending data sheet form.
8.7 Description of Failure—Static bending (flexural) fail-
ures shall be classified in accordance with the appearance of
the fractured surface and the manner in which the failure
develops (Fig. 6). Where appropriate, the fractured surfaces
shall be roughly divided into “brash” and “fibrous,” the term
“brash” indicating abrupt failure and “fibrous” indicating a
fracture showing splinters. Each type of observed failure mode
shall be photographed or sketched.
8.8 Weight and Moisture Content—The specimen shall be
weighed immediately before test, and after the test a moisture
section approximately 1 in. (25 mm) in length shall be cut from
the specimen near the point of failure (see 21.1 and 22.1).
9. Compression Parallel to Grain
9.1 Size of Specimens—The compression-parallel-to-grain
tests shall be made on 2 in. by 2 in. by 8 in. (50 mm by 50 mm
by 200 mm) primary method specimens, or 1 in. by 1 in. by
4 in. (25 mm by 25 mm by 100 mm) secondary method speci-
FIG. 4 Example of a Bearing Block for Static Bending Tests
mens. The actual cross-sectional dimensions and the length
shall be measured (see 22.2).
static bending tests. If required for the purposes of the study, it
9.2 End Surfaces Parallel—Special care shall be used in
shall be permitted to continue both loading and the load-
preparing the compression-parallel-to-grain test specimens to
deflection measurement beyond the maximum load.
ensure that the end grain surfaces will be parallel to each other
NOTE 6—One situation where the user may choose to continue the test
and at right angles to the longitudinal axis. At least one platen
and the load-deflection measurements beyond the maximum load is if the
of the testing machine shall be equipped with a spherical
total energy under the flexural load-deflection curve is a parameter of
bearing to obtain uniform distribution of load over the ends of
concern. In these instances for primary method specimens, it has been
customary to continue the test and record the load-deflection curve beyond the specimen.
the maximum load to a 6 in. (152 mm) deflection or until the specimen
9.3 Speed of Testing—The load shall be applied continu-
fails to support a load of 200 lbf (890 N). For secondary method
ously throughout the test at a rate of motion of the movable
specimens, it has been customary to continue loading to a 3 in. (76 mm)
deflection, or until the specimen fails to support a load of 50 lbf (222 N).
crosshead of 0.003 in./in. (mm/mm) of nominal specimen
length/min (see 22.3).
8.6.2 Deflections of the neutral plane at the center of the
length shall be taken with respect to points in the neutral plane
9.4 Load-Compression Curves:
above the supports. Alternatively, deflection shall be permitted
9.4.1 Load-compression curves shall be taken over a central
to be taken relative to the tension surface at midspan, provided
gauge length not exceeding 6 in. (150 mm) for primary method
that vertical displacements which occur at the reactions are
specimens, and 2 in. (50 mm) for secondary method speci-
taken into account.
mens. Load-compression readings shall be continued until the
8.6.3 Within the proportional limit, deflection readings shall
proportional limit is well passed, as indicated by the curve.
be taken with a yoke-mounted displacement measurement
NOTE 8—See Fig. 7 for a sample compression-parallel-to-grain data
device capable of at least a Class B rating when evaluated in
sheet form.
accordance with Practice E2309. After the proportional limit is
9.4.2 Deformations shall be recorded using displacement
reached, less refinement is necessary in observing deflections.
measurement devices that are capable of a Class A rating when
It shall be permissible to continue the deflection measurement
evaluated in accordance with Practice E2309.
beyond the proportional limit using an alternative means of
9.4.3 Figs. 8 and 9 illustrate two types of compressometers
deflection measurement capable of at least a Class C rating
that have been found satisfactory for wood testing. Similar
when evaluated in accordance with Practice E2309. To char-
apparatus is available for measurements of compression over a
acterize the load-deflection curve, the load and deflection shall
2 in. (50 mm) gauge length.
be measured and recorded at a maximum interval spacing of
0.10 in. (2.5 mm) and after abrupt changes in load. Continuous 9.5 Position of Failures—In order to obtain satisfactory and
load and deflection data acquisition is preferred. uniform results, it is necessary that the failures be made to
8.6.4 When data are recorded manually, the load and de- develop in the body of the specimen. With specimens of
flection of the first failure, the maximum load, and points of uniform cross section, this result can best be obtained when the
sudden change shall be read and shown on the curve sheet, ends are at a very slightly lower moisture content than the
even if they do not occur at one of the regular load or deflection body. With green material, it will usually suffice to close-pile
D143 − 23
FIG. 5 Sample Data Sheet for a Manually Recorded Static Bending Test
the specimens, cover the body with a damp cloth, and expose 9.7 Weight and Moisture Content—See 8.8.
the ends for a short time. For dry material, it shall be permitted
9.8 Ring and Latewood Measurement—When practicable,
to pile the specimens in a similar manner and place them in a
the number of rings per inch (average ring width in millime-
desiccator, if failures in test indicate that a slight end-drying is
ters) and the proportion of summerwood shall be measured
necessary.
over a representative inch (centimeter) of cross section of the
9.6 Descriptions of Failure—Compression failures shall be
test specimen. In determining the proportion of summerwood,
classified in accordance with the appearance of the fractured
it is essential that the end surface be prepared so as to permit
surface (Fig. 10). In case two or more kinds of failures develop,
accurate latewood measurement. When the fibers are broomed
all shall be described in the order of their occurrence; for
over at the ends from sawing, a light sanding, planing, or
example, shearing followed by brooming. Each type of ob-
similar treatment of the ends is recommended.
served failure mode shall be photographed or sketched.
D143 − 23
that complete failure or a 6 in. (150 mm) deflection will result
for all specimens of a species. For all other cases, a 100 lbm
(45 kg) hammer shall be used.
10.7 Deflection Records—When desired, records giving the
deflection for each drop and the set, if any, shall be made until
the first failure occurs. This record will also afford data from
which the exact height of drop can be scaled for at least the first
four falls.
NOTE 9—See Fig. 12 for a sample drum record.
10.8 Drop Causing Failure—The height of drop causing
either complete failure or a 6 in. (150 mm) deflection shall be
observed for each specimen.
10.9 Description of Failure—The failure shall be classified
in accordance with the directions for static bending in 8.7. Each
type of observed failure mode shall be photographed or
sketched.
NOTE 10—See Fig. 13 for a sample of a manually recorded impact
bending data sheet form. A sample data and computation card are shown
in Fig. 14.
10.10 Weight and Moisture Content—See 8.8.
11. Toughness
11.1 A single-blow impact test on a small specimen is
recognized as a valuable and desirable test. Several types of
machines such as the Toughness, Izod and Amsler have been
NOTE 1—The term “cross grain” shall be considered to include all
used, but insufficient information is available to decide whether
deviations of grain from the direction of the longitudinal axis or
longitudinal edges of the specimen. It should be noted that spiral grain one procedure is superior to another, or whether the results by
may be present even to a serious extent without being evident from a
the different test methods can be directly correlated. If the
casual observation.
Toughness machine is used, the following procedure has been
NOTE 2—The presence of cross grain having a slope that deviates more
found satisfactory. To aid in standardization and to facilitate
than 1 in 20 from the longitudinal edges of the specimen shall be cause for
comparisons, the size of the toughness specimen has been
culling the test.
made equal to that accepted internationally.
FIG. 6 Types of Failures in Static Bending
11.2 Size of Specimen—The toughness tests shall be made
on 0.79 in. by 0.79 in. by 11 in. (20 mm by 20 mm by 280 mm)
10. Impact Bending
specimens. The actual height and width at the center and the
10.1 Size of Specimens—The impact bending tests shall be
length shall be measured (see 22.2).
made on 2 in. by 2 in. by 30 in. (50 mm by 50 mm by 760 mm)
11.3 Loading and Span—Center loading and a span length
specimens. The actual height and width at the center and the
of 9.47 in. (240 mm) shall be used. The load shall be applied
length shall be measured (see 22.2).
to a radial or tangential surface on alternate specimens.
10.2 Loading and Span—Use center loading and a span
11.4 Bearing Block—An aluminum tup (Fig. 15) having a
length of 28 in. (710 mm).
radius of ⁄4 in. (19 mm) shall be used in applying the load.
10.3 Bearing Block—A metal tup of curvature correspond-
ing to the bearing block shown in Fig. 4 shall be used in 11.5 Apparatus and Procedure—Make the tests in a pendu-
lum type toughness machine (See Fig. 15). Adju
...

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: D143 − 22 D143 − 23
Standard Test Methods for
Small Clear Specimens of Timber
This standard is issued under the fixed designation D143; 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.
INTRODUCTION
The need to classify wood species by evaluating the physical and mechanical properties of small
clear specimens has always existed. Because of the great variety of species, variability of the material,
continually changing conditions of supply, many factors affecting test results, and ease of comparing
variables, the need will undoubtedly continue to exist.
In the preparation of these methods for testing small clear specimens, consideration was given both
to the desirability of adopting test methods that would yield results comparable to those already
available and to the possibility of embodying such improvements as experience has shown desirable.
In view of the many thousands of tests made under a single comprehensive plan by the U.S. Forest
Service, the former Forest Products Laboratories of Canada (now FPInnovations), and other similar
organizations, these test methods naturally conform closely to the methods used by those institutions.
These test methods are the outgrowth of a study of both American and European experience and
methods. The general adoption of these test methods will tend toward a world-wide unification of
results, permitting an interchange and correlation of data, and establishing the basis for a cumulative
body of fundamental information on the timber species of the world. Many of the figures in this
standard use sample data and computation sheets from testing done in the 1950s and earlier. These
figures remain in the standard because they are still valid depictions of the recording and plotting of
test results and also provide a historical link to the large body of test data on small clear specimens
already in existence for this long-standing test method.
Descriptions of some of the strength tests refer to primary methods and secondary methods. Primary
methods provide for specimens of 2-in. by 2-in. (50 mm by 50 mm) cross section. This size of
specimen has been extensively used for the evaluation of various mechanical and physical properties
of different species of wood, and a large number of data based on this primary method have been
obtained and published.
The 2-in. by 2-in. (50 mm by 50 mm) size has the advantage in that it embraces a number of growth
rings, is less influenced by earlywood and latewood differences than smaller size specimens, and is
large enough to represent a considerable portion of the sampled material. It is advisable to use primary
method specimens wherever possible. There are circumstances, however, when it is difficult or
impossible to obtain clear specimens of 22-in. by 2-in. cross section having the required 30 in. (760
mm) (760 mm) length for static bending tests. With the increasing incidence of smaller second growth
trees, and the desirability in certain situations to evaluate a material which is too small to provide a
2-in. by 2-in. cross section, a secondary method which utilizes a 1-in. by 1-in. (25 mm by 25 mm)
cross section has been included. This cross section is established for compression parallel to grain and
static bending tests, while the 2-in. by 2-in. cross section is retained for impact bending, compression
perpendicular to grain, hardness, shear parallel to grain, cleavage, and tension perpendicular to grain.
Toughness and tension parallel to grain are special tests using specimens of smaller cross section.
These test methods are under the jurisdiction of ASTM Committee D07 on Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental Test Methods
and Properties.
Current edition approved May 15, 2022Nov. 15, 2023. Published June 2022December 2023. Originally approved in 1922. Last previous edition approved in 20212022
as D143 – 21.D143 – 22. DOI: 10.1520/D0143-22.10.1520/D0143-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D143 − 23
The user is cautioned that test results between two different sizes of specimens are not necessarily
directly comparable. Guidance on the effect of specimen size on a property being evaluated is beyond
the scope of these test methods and should be sought elsewhere.
Where the application, measurement, or recording of load and deflection can be accomplished using
electronic equipment and computerized apparatus, such devices are encouraged. It is important that all
data measurement and recording equipment, whether electronic or mechanical, be accurate and
reliable to the degree specified.
D143 − 23
1. Scope
1.1 These test methods cover the determination of various strength and related properties of wood by testing small clear
specimens.
1.1.1 These test methods represent procedures for evaluating the different mechanical and physical properties, controlling factors
such as specimen size, moisture content, temperature, and rate of loading.
1.1.2 Sampling and collection of material is discussed in Practice D5536. Sample data, computation sheets, and cards have been
incorporated, which were of assistance to the investigator in systematizing records.
1.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard. When a weight is prescribed, the
basic inch-pound unit of weight (lbf) and the basic SI unit of mass (Kg) are cited.
1.2 The procedures for the various tests appear in the following order:
Sections
Photographs of Specimens 5
Control of Moisture Content and Temperature 6
Record of Heartwood and Sapwood 7
Static Bending 8
Compression Parallel to Grain 9
Impact Bending 10
Toughness 11
Compression Perpendicular to Grain 12
Hardness 13
Shear Parallel to Grain 14
Cleavage 15
Tension Parallel to Grain 16
Tension Perpendicular to Grain 17
Nail Withdrawal 18
Specific Gravity and Shrinkage in Volume 19
Radial and Tangential Shrinkage 20
Moisture Determination 21
Permissible Variations 22
Calibration 23
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.
2. Referenced Documents
2.1 ASTM Standards:
D9 Terminology Relating to Wood and Wood-Based Products
D198 Test Methods of Static Tests of Lumber in Structural Sizes
D2395 Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials
D3043 Test Methods for Structural Panels in Flexure
D4442 Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
D4761 Test Methods for Mechanical Properties of Lumber and Wood-Based Structural Materials
D5536 Practice for Sampling Forest Trees for Determination of Clear Wood Properties
E4 Practices for Force Calibration and Verification of Testing Machines
E2309 Practices for Verification of Displacement Measuring Systems and Devices Used in Material Testing Machines
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D143 − 23
3. Summary of Test Methods
3.1 The mechanical tests are static bending, compression parallel to grain, impact bending toughness, compression perpendicular
to grain, hardness, shear parallel to grain, cleavage, tension parallel to grain, tension-perpendicular-to-grain, and nail-withdrawal
tests. These tests are permitted for both green and air-dry material as specified in these test methods. In addition, test methods for
evaluating such physical properties as specific gravity, shrinkage in volume, radial shrinkage, and tangential shrinkage are
presented.
NOTE 1—The test for shearing strength perpendicular to the grain (sometimes termed “vertical shear”) is not included as one of the principal mechanical
tests since in such a test the strength is limited by the shearing resistance parallel to the grain.
4. Significance and Use
4.1 These test methods cover tests on small clear specimens of wood that are made to provide the following:
4.1.1 Data for comparing the mechanical properties of various species,
4.1.2 Data for the establishment of correct strength functions, which in conjunction with results of tests of timbers in structural
sizes (see Test Methods D198 and Test Methods D4761), afford a basis for establishing allowable stresses, and
4.1.3 Data to determine the influence on the mechanical properties of such factors as density, locality of growth, position in cross
section, height of timber in the tree, change of properties with seasoning or treatment with chemicals, and change from sapwood
to heartwood.
5. Photographs of Specimens
5.1 Four of the static bending specimens from each species shall be selected for photographing, as follows: two average growth,
one fast growth, and one slow growth. These specimens shall be photographed in cross section and on the radial and tangential
surfaces. Fig. 1 is a typical photograph of a cross section of 2-in. by 2-in. (50 mm by 50 mm) test specimens, and Fig. 2 is the
tangential surface of such specimens.
FIG. 1 Cross Sections of Bending Specimens Showing Different Rates of Growth of Longleaf Pine (2-in. by 2-in. (50 mm by 50 mm)
Specimens)
D143 − 23
FIG. 2 Tangential Surfaces of Bending Specimens of Different Rates of Growth of Jeffrey Pine 2-in. by 2-in. by 30-in. (50 mm by 50 mm
by 760 mm) Specimens
6. Control of Moisture Content and Temperature
6.1 In recognition of the significant influence of temperature and moisture content and temperature on the strength of wood, it is
highly desirable that these factors be controlled physical and mechanical properties of wood, these factors shall be controlled and
reported to ensure comparable test results.
NOTE 2—It is desirable that the testing room and the room for preparation of test specimens are temperature- and humidity-controlled.
6.2 Control of Moisture Content—Specimens for the test in the air-dryMoisture content shall be managed based on the objective
of the test: Specimens for tests in the green condition shall be dried to approximately constant weight before test. If any changes
in moisture content occur during final preparation of specimens, the specimens shall be reconditioned to stored and manipulated
in such a manner that their moisture content remains above the fiber saturation point; specimens for in-situ tests shall be maintained
at the in-situ moisture content; and specimens for tests in the air-dry condition shall be conditioned to approximately constant
weight before the test. Tests shall be carried out in such a manner that largeinfluential changes in moisture content will not occur.
To prevent such changes, it is desirable that the testing roomdo not occur during the tests.
3,4
NOTE 3—USDA Technical Bulletin 479 describes the sensitivity of wood properties to moisture content changes. This reference may be useful when
determining influential moisture content changes relative to the wood properties being tested. and rooms for preparation of test specimens have
some means of humidity control.
6.3 Control of Temperature—Temperature and relative humidity together affect wood strength by fixing its equilibrium moisture
content. The mechanical properties of wood are also affected by temperature alone. When tested, The temperature of the specimens
shall be at a temperature of 68 6 6 °F (20 6 3 °C). The temperature 68 °F 6 6 °F (20 °C 6 3 °C) except when the effects of other
temperatures are to be evaluated. The conditioning temperature and the temperature at the time of test shall in all instances be
recorded as a specific part of the test record.be recorded.
NOTE 4—Temperature and relative humidity affect the equilibrium moisture content and wood properties. Historically, when testing wood in the air-dry
condition, the equilibrium moisture content is based on hygrothermal conditioning at a temperature of 68 °F 6 6 °F (20 °C 6 3 °C) and 65 % 6 5 %
relative humidity.
7. Record of Heartwood and Sapwood
7.1 Proportion of Sapwood—If heartwood and sapwood present in the specimen can be distinguished by visual inspection, the
proportion of sapwood present shall be estimated as required for the purposes of the test program and recorded for each test
specimen.
Markwardt, L.J. and T.R.J. Wilson. 1935. Strength and related properties of woods grown in the United States.Technical Bulletin No. 479. Forest Products Laboratory,
USDA, Washington, DC.
Available from USDA National Agricultural Library Digital Collections (https://naldc.nal.usda.gov).
D143 − 23
8. Static Bending
8.1 Size of Specimens—The static bending tests shall be made on 2 in. by 2 in. by 30 in. (50 mm by 50 mm by 760 mm) primary
method specimens or 1 in. by 1 in. by 16 in. (25 mm by 25 mm by 410 mm) secondary method specimens. The actual height and
width at the center and the length shall be measured (see 22.2).
8.2 Loading Span and Supports—Use center loading and a span length of 28 in. (710 mm) for the primary method and 14 in. 14 in.
(360 mm) for the secondary method. These spans were established in order to maintain a minimum span-to-depth ratio of 14. Both
supporting knife edges shall be provided with bearing plates and rollers of such thickness that the distance from the point of support
to the central plane is not greater than the depth of the specimen (Fig. 3). The knife edges shall be adjustable laterally to permit
adjustment for slight twist in the specimen.
NOTE 5—An example of laterally adjustable supports is provided in Figure 1 of Test Methods D3043.
8.3 Bearing Block—A rigid bearing block having a radius of 3 in. (76 mm) and a chord length of not less than 3 ⁄16 in. (97 mm)
(97 mm) that is fixed from rotation shall be used for applying the load for primary method specimens. An example is provided in
Fig. 4. A similar block having a radius of 1 ⁄2 in. (38 mm) for a chord length of not less than 2 in. (50 mm) shall be used for
secondary method specimens. The bearing block shall be fabricated with a material that will not appreciably deform under load.
8.4 Placement of Growth Rings—The specimen shall be placed so that the load will be applied through the bearing block to the
tangential surface nearest the pith.
8.5 Speed of Testing—The load shall be applied continuously throughout the test at a rate of motion of the movable crosshead of
0.10 in. (2.5 mm)/min, for primary method specimens, and at a rate of 0.05 in. (1.3 mm)/min for secondary method specimens (see
22.3).
8.6 Load-Deflection Curves:
8.6.1 At a minimum, the load-deflection curves shall be recorded and the test continued up to the maximum load for all static
bending tests. If required for the purposes of the study, it shall be permitted to continue both loading and the load-deflection
measurement beyond the maximum load.
FIG. 3 Static Bending Test Assembly Showing Test Method of Load Application, Specimen Supported on Rollers and Laterally Adjust-
able Knife Edges, and Test Method of Measuring Deflection at Neutral Axis by Means of Yoke and Displacement Measurement Device
D143 − 23
FIG. 4 Example of a Bearing Block for Static Bending Tests
NOTE 6—One situation where the user may choose to continue the test and the load-deflection measurements beyond the maximum load is if the total
energy under the flexural load-deflection curve is a parameter of concern. In these instances for primary method specimens, it has been customary to
continue the test and record the load-deflection curve beyond the maximum load to a 6 in. (152 mm) deflection or until the specimen fails to support a
load of 200 lbf (890 N). For secondary method specimens, it has been customary to continue loading to a 3 in. (76 mm) deflection, or until the specimen
fails to support a load of 50 lbf (222 N).
8.6.2 Deflections of the neutral plane at the center of the length shall be taken with respect to points in the neutral plane above
the supports. Alternatively, deflection shall be permitted to be taken relative to the tension surface at midspan, provided that vertical
displacements which occur at the reactions are taken into account.
8.6.3 Within the proportional limit, deflection readings shall be taken with a yoke-mounted displacement measurement device
capable of at least a Class B rating when evaluated in accordance with Practice E2309. After the proportional limit is reached, less
refinement is necessary in observing deflections. It shall be permissible to continue the deflection measurement beyond the
proportional limit using an alternative means of deflection measurement capable of at least a Class C rating when evaluated in
accordance with Practice E2309. To characterize the load-deflection curve, the load and deflection shall be measured and recorded
at a maximum interval spacing of 0.10 in. (2.5 mm) and after abrupt changes in load. Continuous load and deflection data
acquisition is preferred.
8.6.4 When data are recorded manually, the load and deflection of the first failure, the maximum load, and points of sudden change
shall be read and shown on the curve sheet, even if they do not occur at one of the regular load or deflection increments. When
data are recorded electronically, the data recording rate shall be sufficient to capture the same points so that they can be similarly
reported.
NOTE 7—See Fig. 5 for a sample static bending data sheet form.
8.7 Description of Failure—Static bending (flexural) failures shall be classified in accordance with the appearance of the fractured
surface and the manner in which the failure develops (Fig. 6). Where appropriate, the fractured surfaces shall be roughly divided
into “brash” and “fibrous”,“fibrous,” the term “brash” indicating abrupt failure and “fibrous” indicating a fracture showing
splinters. Each type of observed failure mode shall be photographed or sketched.
8.8 Weight and Moisture Content—The specimen shall be weighed immediately before test, and after the test a moisture section
approximately 1 in. (25 mm) in length shall be cut from the specimen near the point of failure (see 21.1 and 22.1).
D143 − 23
FIG. 5 Sample Data Sheet for a Manually Recorded Static Bending Test
9. Compression Parallel to Grain
9.1 Size of Specimens—The compression-parallel-to-grain tests shall be made on 2 in. by 2 in. by 8 in. (50 mm by 50 mm by 200
mm) primary method specimens, or 1 by 1 by 4 in. (25 by 25 by 100 mm) 1 in. by 1 in. by 4 in. (25 mm by 25 mm by 100 mm)
secondary method specimens. The actual cross-sectional dimensions and the length shall be measured (see 22.2).
9.2 End Surfaces Parallel—Special care shall be used in preparing the compression-parallel-to-grain test specimens to ensure that
the end grain surfaces will be parallel to each other and at right angles to the longitudinal axis. At least one platen of the testing
machine shall be equipped with a spherical bearing to obtain uniform distribution of load over the ends of the specimen.
D143 − 23
NOTE 1—The term “cross grain” shall be considered to include all deviations of grain from the direction of the longitudinal axis or longitudinal edges
of the specimen. It should be noted that spiral grain may be present even to a serious extent without being evident from a casual observation.
NOTE 2—The presence of cross grain having a slope that deviates more than 1 in 20 from the longitudinal edges of the specimen shall be cause for
culling the test.
FIG. 6 Types of Failures in Static Bending
9.3 Speed of Testing—The load shall be applied continuously throughout the test at a rate of motion of the movable crosshead of
0.003 in./in. (mm/mm) of nominal specimen length/min (see 22.3).
9.4 Load-Compression Curves:
9.4.1 Load-compression curves shall be taken over a central gauge length not exceeding 6 in. (150 mm) for primary method
specimens, and 2 in. (50 mm) for secondary method specimens. Load-compression readings shall be continued until the
proportional limit is well passed, as indicated by the curve.
NOTE 8—See Fig. 7 for a sample compression-parallel-to-grain data sheet form.
9.4.2 Deformations shall be recorded using displacement measurement devices that are capable of a Class A rating when evaluated
in accordance with Practice E2309.
9.4.3 Figs. 8 and 9 illustrate two types of compressometers that have been found satisfactory for wood testing. Similar apparatus
is available for measurements of compression over a 2 in. (50 mm) gauge length.
9.5 Position of Failures—In order to obtain satisfactory and uniform results, it is necessary that the failures be made to develop
in the body of the specimen. With specimens of uniform cross section, this result can best be obtained when the ends are at a very
slightly lower moisture content than the body. With green material, it will usually suffice to close-pile the specimens, cover the
body with a damp cloth, and expose the ends for a short time. For dry material, it shall be permitted to pile the specimens in a
similar manner and place them in a desiccator, if failures in test indicate that a slight end-drying is necessary.
D143 − 23
FIG. 7 Sample Data Sheet for a Manually Recorded Compression-Parallel-to-Grain Test
9.6 Descriptions of Failure—Compression failures shall be classified in accordance with the appearance of the fractured surface
(Fig. 10). In case two or more kinds of failures develop, all shall be described in the order of their occurrence; for example, shearing
followed by brooming. Each type of observed failure mode shall be photographed or sketched.
9.7 Weight and Moisture Content—See 8.8.
9.8 Ring and Latewood Measurement—When practicable, the number of rings per inch (average ring width in millimeters) and
the proportion of summerwood shall be measured over a representative inch (centimeter) of cross section of the test specimen. In
D143 − 23
The wire in the lower right-hand corner connects the compressometer with the recording unit.
FIG. 8 Compression-Parallel-to-Grain Test Assembly Using an Automatic Type of Compressometer to Measure Deformations
(The wire in the lower right-hand corner connects the compressometer with the recording unit.)
FIG. 9 Compression-Parallel-to-Grain Test Assembly Showing Method of Measuring Deformations by Means of Roller-Type Compres-
someter
determining the proportion of summerwood, it is essential that the end surface be prepared so as to permit accurate latewood
measurement. When the fibers are broomed over at the ends from sawing, a light sanding, planing, or similar treatment of the ends
is recommended.
10. Impact Bending
10.1 Size of Specimens—The impact bending tests shall be made on 2 in. by 2 in. by 30 in. (50 mm by 50 mm by 760 mm)
specimens. The actual height and width at the center and the length shall be measured (see 22.2).
D143 − 23
FIG. 10 Types of Failures in Compression
10.2 Loading and Span—Use center loading and a span length of 28 in. (710 mm).
10.3 Bearing Block—A metal tup of curvature corresponding to the bearing block shown in Fig. 4 shall be used in applying the
load.
10.4 Placement of Growth Rings—The specimen shall be placed so that the load will be applied through the bearing block to the
tangential surface nearest the pith.
10.5 Procedure—Make the tests by increment drops in a Hatt-Turner or similar impact machine (see Fig. 11). The first drop shall
be 1 in. (25 mm), after which increase the drops by 1 in. increments until a height of 10 in. (250 mm) is reached. Then use a 2
in. (50 mm) increment until complete failure occurs or a 6 in. (150 mm) deflection is reached.
10.6 Weight of Hammer—A 50 lbm (22.5 kg) hammer shall be used with drops up to the capacity of the machine provided that
complete failure or a 6 in. (150 mm) deflection will result for all specimens of a species. For all other cases, a 100 lbm (45 kg)
hammer shall be used.
D143 − 23
FIG. 11 Hatt-Turner Impact Machine, Illustrating Test Method of Conducting Impact Bending Test
10.7 Deflection Records—When desired, records giving the deflection for each drop and the set, if any, shall be made until the first
failure occurs. This record will also afford data from which the exact height of drop can be scaled for at least the first four falls.
NOTE 9—See Fig. 12 for a sample drum record.
FIG. 12 S
...