ASTM F1880-98e1
(Test Method)Standard Test Method for the Determination of Percent of Let-Off for Archery Bows
Standard Test Method for the Determination of Percent of Let-Off for Archery Bows
SCOPE
1.1 This test method establishes the procedure to be used to determine the percent of let-off for archery bows.
1.2 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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
e1
Designation: F 1880 – 98
Standard Test Method for the
1
Determination of Percent of Let-Off for Archery Bows
This standard is issued under the fixed designation F 1880; 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 (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—Sections 3.1.1, 3.1.2, 5, 5.1, and 5.3 were editorially updated in September 2003.
1. Scope 3.1.5 conventional bow, n—a bow constructed in the con-
ventional manner, having two flexing limbs extending out-
1.1 This test method establishes the procedure to be used to
wardly in opposite directions from a handle. A single shooting
determine the percent of let-off for archery bows.
string of a length shorter than the bow, connects the extreme
1.2 This standard does not purport to address all of the
ends of the limbs causing them to assume a prestressed flexed
safety concerns, if any, associated with its use. It is the
condition. Drawing the bow causes additional bending and
responsibility of the user of this standard to establish appro-
stressing of the limbs, storing the energy necessary to propel
priate safety and health practices and determine the applica-
the arrow. Control of the force-draw characteristic of the bow
bility of regulatory limitations prior to use.
is exercised entirely by the static and dynamic geometry of the
2. Referenced Documents flexing limbs.
3.1.6 draw, n—to move the shooting string of a bow from
2.1 ASTM Standards:
the rest or brace position toward the fully drawn position by
F 1832 Method for Determining the Force-Draw and Let-
2
applying force to said string. Such action causes the limbs of
Down Curves for Archery Bows
the bow to bend and store energy. Moving the string from brace
3. Terminology
height to the full-draw position corresponds to the draw cycle
of a bow.
3.1 Definitions:
3.1.7 draw force, n—that level of force necessary and
3.1.1 ATA—an acronym for the Archery Trade Association.
coincidental with drawing a bow to a specific position within
3.1.2 ATA draw length, n—the perpendicular distance from
its draw length.
the point where the shooting string of the bow contacts the
3.1.8 force-draw curve, n—the curve obtained when the
bottom of the nock slot of the arrow, to a line parallel to the
draw force is plotted versus the draw length for a given bow.
string at brace height through the pivot or low point of the hand
3.1.9 full draw, n—the position in a draw cycle of a bow
grip (draw length-pivot point), plus a standard dimension of 1
3
from which the string of the bow is released and the force
⁄4 in. (44.5 mm). Draw length shall be measured with the
applied to the rear of the arrow to commence the launch. The
arrow in the full draw position.
full-draw position of individual archers will vary due to
3.1.3 brace height, n—the distance in inches or millimeters
personal physical characteristics and shooting style. Archery
from the shooting string of a bow to the pivot or low point of
bows are specified as to the range of draw length that they will
the hand grip, measured perpendicular to the string.
accommodate to permit archers to select a size that will fit
3.1.4 compound bow, n—a type of bow that imposes a
them. Precise draw length is less of a factor on conventional
secondary system of control of the force-draw characteristic on
bows as compared to compound bows since it is ideal to match
the usual limb geometry control system of the conventional
the draw length of the archer to the position of maximum
bow. This secondary control system can be composed of cams,
let-off in the draw cycle of the compound bow. The position of
levers, cables, or other elements, and combination thereof. The
maximum let-off for compound bows usually is adjustable
dual control system permits great versatility in the design of the
within specified limits.
force-draw characteristic and simplifies the inclusion of let-off.
3.1.10 holding force, n—the force required to retain the
In general, it is normal for compound bows to have greater
bowstring of a drawn bow at a specific draw length.
stored energy than conventional bows for a given level of peak
3.1.11 let-down curve, n—the curve obtained when the
or maximum draw weight.
force necessary to restrain the bow from returning to brace
height is plotted versus the draw length.
1
This test method is under the jurisdiction of ASTM Committee F08 on Sports
3.1.12 let-down force, n—the force required to retain the
Equipment and Facilities and is the direct responsibility of Subcommittee F08.16 on
bowstring of the drawn bow at a specific draw length during
Archery Products.
the let-down cycle. This force
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.