ASTM F2398-11(2020)

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: F2398 − 11 (Reapproved 2020) An American National Standard
Standard Test Method for
Measuring Moment of Inertia and Center of Percussion of a
Baseball or Softball Bat
This standard is issued under the fixed designation F2398; 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.
1. Scope F2219 Test Methods for Measuring High-Speed Bat Perfor-
mance
1.1 Method for determining the moment of inertia (MOI),
the center of percussion (COP), and the balance point (BP) of
3. Terminology
baseball and softball bats.These physical properties are used in
3.1 Definitions of Terms Specific to This Standard:
Test Method F1881, Test Method F1890, and Test Methods
3.1.1 balance point (BP), n—the distance to the center of
F2219.
mass measured from the knob end of the bat.
1.2 The MOI, COP, and BP are measured in the laboratory
3.1.2 center of percussion (COP), n—also known as the
on test equipment meeting the requirements defined in this test
center of oscillation. Forces and impacts at this location will
method.
not induce reactions at the pivot point, 6 in. (152 mm) from the
1.3 The values stated in inch-pound units are to be regarded
knob end of the bat.
as standard. The values given in parentheses are mathematical
3.1.3 cycle, n—one complete oscillation of a pendulum
conversions to SI units that are provided for information only
supported at the pivot point, 6 in. (152 mm) from the knob end
and are not considered standard.
of the bat.
1.4 This standard does not purport to address all of the
3.1.4 moment of inertia (MOI), n—also known as the mass
safety concerns, if any, associated with its use. It is the
moment of inertia, the measure of the bat’s resistance to
responsibility of the user of this standard to establish appro-
changes in its rotation rate about the pivot point, 6 in. (152
priate safety, health, and environmental practices and deter-
mm) from the knob end of the bat.
mine the applicability of regulatory limitations prior to use.
3.1.5 period, n—the time required for a pendulum to oscil-
1.5 This international standard was developed in accor-
late through one complete cycle.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Significance and Use
Development of International Standards, Guides and Recom-
4.1 This test method offers a laboratory means to measure
mendations issued by the World Trade Organization Technical
the inertial properties of bats, specifically weight, balance
Barriers to Trade (TBT) Committee.
point, center of percussion, and MOI, in support of other test
methods including the ASTM standards referenced in this
2. Referenced Documents
document.
2.1 ASTM Standards:
4.2 Use of this test method can provide sports governing
F1881 Test Method for Measuring Baseball Bat Perfor-
bodies the means to establish rules regarding the physical
mance Factor (Withdrawn 2014)
properties of bats, specifically MOI.
F1890 Test Method for Measuring Softball and Baseball Bat
Performance Factor
5. Apparatus
5.1 Bat MOI Test Apparatus:
This test method is under the jurisdiction of ASTM Committee F08 on Sports
5.1.1 Ruler, suitable for measuring lengths up to 42 in.
Equipment, Playing Surfaces, and Facilities and is the direct responsibility of
Subcommittee F08.26 on Baseball and Softball Equipment.
(1067 mm) to the nearest 0.03 in. (0.8 mm).
Current edition approved July 1, 2020. Published August 2020. Originally
5.1.2 Weight Scales, suitable for measuring weight up to 48
approved in 2004. Last previous edition approved in 2015 as F2398 – 11 (2015).
oz (1361 g) to the nearest 0.0035 oz (0.1 g).
DOI: 10.1520/F2398-11R20.
5.1.3 Electronic Timer, suitable device sufficiently accurate
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
for measuring time to the nearest 1 µs (0.000001 s).
Standards volume information, refer to the standard’s Document Summary page on
5.1.4 Pendulum Stand—A frame with a pivoting bat collar-
the ASTM website.
3 clamp large enough to allow a bat held in a vertical position to
The last approved version of this historical standard is referenced on
www.astm.org. swing freely (see Fig. 1).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2398 − 11 (2020)
FIG. 1 MOI Fixture
5.1.5 Bat Collar-Clamp—Alightweight clamp or collar that 6.4 Mass Moment of Inertia Calibration—Using the mea-
can hold the weight of a bat and provide a fixed pivot location. sured properties of the calibration rod from 6.2 and 6.3 and
The clamp shall be rotationally balanced and have a maximum following 7.2 and 7.3, the measured MOI of the calibration rod
2 2 2 2
MOI of 4 oz-in. (73 kg-mm ) measured about the bat pivot should be within 650 oz-in. (916 kg-mm ) of the target MOI,
location (see Fig. 1). The MOI of the clamp shall not change I . If t
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