APPENDIX II design of clubs
A player in doubt as to the conformity of a club should consult
the USGA.
A manufacturer should submit to the USGA a sample of a club
to be manufactured for a ruling as to whether the club conforms
with the Rules. The sample becomes the property of the
USGA for reference purposes. If a manufacturer fails to submit
a sample or, having submitted a sample, fails to await a ruling
before manufacturing and/or marketing the club, the manufacturer
assumes the risk of a ruling that the club does not conform
with the Rules.
The following paragraphs prescribe general regulations for
the design of clubs, together with specifications and interpretations.
Further information relating to these regulations
and their proper interpretation is provided in “A Guide to the
Rules on Clubs and Balls.”
Where a club, or part of a club, is required to meet a specification
within the Rules, it must be designed and manufactured
with the intention of meeting that specification.
126 Appendix II
Appendix II 127
1. Clubs
g a. General
A club is an implement designed to be used for striking the
ball and generally comes in three forms: woods, irons and
putters distinguished by shape and intended use. A putter is a
club with a loft not exceeding ten degrees designed primarily
for use on the putting green.
The club must not be substantially different from the traditional
and customary form and make. The club must be composed of
a shaft and a head and it may also have material added to the
shaft to enable the player to obtain a firm hold (see 3 below). All
parts of the club must be fixed so that the club is one unit, and
it must have no external attachments. Exceptions may be made
for attachments that do not affect the performance of the club.
g b. Adjustability
All clubs may incorporate mechanisms for weight adjustment.
Other forms of adjustability may also be permitted upon
evaluation by the USGA. The following requirements apply to
all permissible methods of adjustment:
(i) the adjustment cannot be readily made;
(ii) all adjustable parts are firmly fixed and there is no
reasonable likelihood of them working loose during a
round; and
(iii) all configurations of adjustment conform with the Rules.
During a stipulated round, the playing characteristics of a
club must not be purposely changed by adjustment or by
any other means (see Rule 4-2a).
g c. Length
The overall length of the club must be at least 18 inches
(0.457 m) and, except for putters, must not exceed 48 inches
Club length
60º
Figure I
(1.219 m). For woods and irons, the measurement of length
is taken when the club is lying on a horizontal plane and the
sole is set against a 60 degree plane as shown in Fig. I. The
length is defined as the distance from the point of the intersection
between the two planes to the top of the grip. For putters,
the measurement of length is taken from the top of the
grip along the axis of the shaft or a straight line extension of
it to the sole of the club.
g d. Alignment
When the club is in its normal
address position the shaft must
be so aligned that:
(i) the projection of the
straight part of the shaft
on to the vertical plane
through the toe and
heel must diverge from
the vertical by at least
10 degrees (see Fig. II ). If
the overall design of the
club is such that the player can effectively use the club
in a vertical or close-to-vertical position, the shaft may
be required to diverge from
the vertical in this plane by as
much as 25 degrees;
(ii) the projection of the straight
part of the shaft on to the vertical
plane along the intended
line of play must not diverge
from the vertical by more
than 20 degrees forward or 10
degrees backward (see Fig. III ).
Except for putters, all of the heel
portion of the club must lie within
0.625 inches (15.88 mm) of the plane
128 Appendix II
Sole
Toe Heel
Shaft
Axis
10º
Min
Figure
II
20º
Max
10º
Max
Back
Face
Figure
III
Appendix II 129
containing the axis of the
straight part of the shaft
and the intended (horizontal)
line of play (see Fig. IV).
2. Shaft
g a. Straightness
The shaft must be straight
from the top of the grip
to a point not more than
5 inches (127 mm) above
the sole, measured from
the point where the shaft
ceases to be straight along
the axis of the bent part of
the shaft and the neck and/
or socket (see Fig. V).
g b. Bending and Twisting Properties
At any point along its length, the shaft must:
(i) bend in such a way that the deflection
is the same regardless of how
the shaft is rotated about its
longitudinal axis; and
(ii) twist the same amount in
both directions.
Bent Shaft
Axis 5’’ Max
Shaft straightness
measurement
ends here
Sole
Figure V
Shaft
Axis
Shaft
Axis
Sole
Sole
0.625
Max
0.625 Max
Figure
IV
g c. Attachment to
Clubhead
The shaft must be
attached to the clubhead
at the heel either directly
or through a single
plain neck and/or socket.
The length from the top
of the neck and/or socket
to the sole of the club
must not exceed 5 inches
(127 mm), measured
along the axis of, and
following any bend in,
the neck and/or socket (see Fig. VI).
Exception for Putters: The shaft or neck or socket of a putter
may be fixed at any point in the head.
3. Grip (see Fig. VII)
The grip consists of material
added to the shaft to enable the
player to obtain a firm hold. The
grip must be fixed to the shaft,
must be straight and plain in
form, must extend to the end of
the shaft and must not be molded
for any part of the hands. If no
material is added, that portion of
the shaft designed to be held by
the player must be considered the
grip.
(i) F or clubs other than putters
the grip must be circular
in cross-section, except
that a continuous, straight,
slightly raised rib may be
incorporated along the full
Neck or socket
measurement
starts here
Neck or socket
axis 5’’ max
Sole Sole
Dotted line
shows neck
and socket
measurement
to the sole
5’’ max
Figure VI
Circular
cross-section
Non-circular
cross-section
(putters only)
Waist
(not permitted)
Bulge
(not permitted)
Figure VII
130 Appendix II
Appendix II 131
length of the grip, and a slightly indented spiral is permitted
on a wrapped grip or a replica of one.
(ii) A putter grip may have a non-circular cross-section,
provided the cross-section has no concavity, is symmetrical
and remains generally similar throughout the
length of the grip. (See Clause (v), below.)
(iii) The grip may be tapered but must not have any bulge
or waist. Its cross-sectional dimensions measured in any
direction must not exceed 1.75 inches (44.45 mm).
(iv) F or clubs other than putters the axis of the grip must
coincide with the axis of the shaft.
(v) A putter may have two grips, provided each is circular
in cross-section, the axis of each coincides with the
axis of the shaft, and they are separated by at least
1.5 inches (38 mm).
4. Clubhead
g a. Plain in Shape
The clubhead must be generally plain in shape. All parts must
be rigid, structural in nature and functional. The clubhead or
its parts must not be designed to resemble any other object.
It is not practicable to define plain in shape precisely and
comprehensively. However, features which are deemed to be
in breach of this requirement and are therefore not permitted
include, but are not limited to:
(i) All Clubs
• holes through the face;
• holes through the head (some exceptions may be made
for putters and cavity back irons);
• facsimiles of golf balls or actual golf balls incorporated
into the head;
• features that are for the purpose of meeting dimensional
specifications;
• features that extend into or ahead of the face;
• features that extend significantly above the top line of
the head;
• furrows in or runners on the head that extend into
the face (some exceptions may be made for putters);
and
• optical or electronic devices.
(ii) Woods and Irons
• all features listed in (i) above;
• cavities in the outline of the heel and/or the toe of the
head that can be viewed from above;
• severe or multiple cavities in the outline of the back
of the head that can be viewed from above;
• transparent material added to the head with the
intention of rendering conforming a feature that is
not otherwise permitted; and
• features that extend beyond the outline of the head
when viewed from above.
g b. Dimensions, Volume and Moment of Inertia
(i) Woods
When the club is in a 60 degree lie angle, the dimensions
of the clubhead must be such that:
• the distance from the heel to the toe of the clubhead is
greater than the distance from the face to the back;
• the distance from the heel to the toe of the clubhead
is not greater than 5 inches (127 mm); and
• the distance from the sole to the crown of the clubhead,
including any permitted features, is not greater
than 2.8 inches (71.12 mm).
These dimensions are measured on horizontal lines
between vertical projections of the outermost points of:
• the heel and the toe; and
• the face and the back (see Fig. VIII , dimension A); and
on vertical lines between the horizontal projections of
132 Appendix II
Appendix II 133
the outermost
points of the
sole and the
crown (see Fig.
VIII , dimension
B). If the
outermost point of the heel is not clearly defined, it is
deemed to be 0.875 inches (22.23 mm) above the horizontal
plane on which the club is lying (see Fig. VIII ,
dimension C).
The volume of the clubhead must not exceed 460 cubic
centimeters (28.06 cubic inches), plus a tolerance of 10
cubic centimeters (0.61 cubic inches).
When the club is in a 60 degree lie angle, the moment
of inertia component around the vertical axis through
the clubhead’s center of gravity must not exceed
5900 g cm² (32.259 oz in²), plus a test tolerance of
100 g cm² (0.547 oz in²).
(ii) Irons
When the clubhead is in its normal address position,
the dimensions of the head must be such that the distance
from the heel to the toe is greater than the distance
from the face to the back.
(iii) Putters (see Fig. IX )
When the clubhead is in its normal address position,
the dimensions of the head must be such that:
• the distance from the heel to the toe is greater than
the distance from the face to the back;
• the distance from the heel to the toe of the head is
less than or equal to 7 inches (177.8 mm);
60º
Heel
Toe
Crown
C
B
0.875 ’’
Sole
Face Back
Figure VIII A
• the distance from the heel to the toe of the face is
greater than or equal to two thirds of the distance
from the face to the back of the head;
• the distance from the heel to the toe of the face is
greater than or equal to half of the distance from the
heel to the toe of the head;
• the distance from the sole to the top of the head,
including any permitted features, is less than or equal
to 2.5 inches (63.5 mm).
For traditionally shaped heads, these dimensions will be
measured on horizontal lines between vertical projections
of the outermost points of:
• the heel and the toe of the head;
• the heel and the toe of the face;
• the face and the back;
and on vertical lines between the horizontal projections of
the outermost points of the sole and the top of the head.
For unusually shaped heads, the heel to toe measurement
may be made at the face.
g c. Spring Effect and Dynamic Properties
The design, material and/or construction of, or any treatment
to, the clubhead (which includes the club face) must not:
(i) have the effect of a spring which exceeds the limit set
forth in the Pendulum Test Protocol on file with the
USGA, or
134 Appendix II
Figure IX
Top View Face View
Back
A
D
B C
Face
A 7
B 2/3 C
B 1/2 A
A>C
D 2.5
A ≤ 7"
B ≥ 2/3 C
B ≥ 1/2 A
A > C
D ≤ 2.5"
Appendix II 135
(ii) incorporate features or technology, including, but not
limited to separate springs or spring features, that have
the intent of, or the effect of, unduly influencing the
clubhead’s spring effect, or
(iii) unduly influence the movement of the ball.
Note: (i) above does not apply to putters.
g d. Striking Faces
The clubhead must have only one striking face, except that a
putter may have two such faces if their characteristics are the
same, and they are opposite each other.
5. Club Face
g a. General
The face of the club must be hard and rigid and must not
impart significantly more or less spin to the ball than a standard
steel face (some exceptions may be made for putters).
Except for such markings listed below, the club face must be
smooth and must not have any degree of concavity.
g b. Impact Area Roughness
and Material
Except for markings specified in the following paragraphs, the
surface roughness within the area where impact is intended (the
“impact area”) must not exceed
that of decorative sandblasting, or
of fine milling (see Fig. X).
The whole of the impact area
must be of the same material
(exceptions may be made for
clubheads made of wood).
g c. Impact Area Markings
If a club has grooves and/or
punch marks in the impact area, they must be designed
and manufactured to meet the following specifications:
(i) Grooves
• Grooves must not have sharp edges or raised lips (test
on file).
Illustrative
impact area
Figure X
• Grooves must be straight and parallel.
• Grooves must have a symmetrical cross-section and
have sides which do not converge (see Fig. XI ).
• The width, spacing and cross-section of the grooves
must be consistent throughout the impact area.
• Any rounding of groove edges must be in the form of a
radius which does not exceed 0.020 inches (0.508 mm).
• The width of each groove must not exceed 0.035 inches
(0.9 mm), using the 30 degree method of measurement
on file with the USGA.
• The distance between edges of adjacent grooves must
not be less than three times the width of the grooves,
and not less than 0.075 inches (1.905 mm).
• The depth of each groove must not exceed 0.020 inches
(0.508 mm).
(ii) Punch Marks
• The area of any such mark must not exceed 0.0044
square inches (2.84 sq. mm).
• The distance between adjacent punch marks (or
between punch marks and grooves) must not be less
than 0.168 inches (4.27 mm), measured from center
to center.
• The depth of any punch mark must not exceed 0.040
inches (1.02 mm).
• P unch marks must not have sharp edges or raised lips
(test on file).
136 Appendix II
Conforming
30º 30º
Converging Asymmetric
Non-Conforming
Axis of
Symmetry
Groove width
(max 0.035”)
Groove depth
(max 0.020”) Figure XI
Appendix II 137
g d. Decorative Markings
The center of the impact area may be indicated by a design
within the boundary of a square whose sides are 0.375 inches
(9.53 mm) in length. Such a design must not unduly influence
the movement of the ball. Decorative markings are permitted
outside the impact area.
g e. Non-metallic Club Face Markings
The above specifications do not apply to clubheads made of
wood on which the impact area of the face is of a material of
hardness less than the hardness of metal and whose loft angle
is 24 degrees or less, but markings which could unduly influence
the movement of the ball are prohibited.
g f. Putter Face Markings
Any markings on the face of a putter must not have sharp
edges or raised lips. The specifications with regard to roughness,
material and markings in the impact area do not apply.
