Rules of Golf - Appendix II: Design of Clubs - Driving the Green - Golf Courses, History, Information, Instruction, Tips, Techniques, and More

A player in doubt as to the conformity of a club should consult the United States Golf Association (USGA).
A manufacturer should submit to the USGA a sample of a club, which is to be manufactured, for a ruling as to whether the club conforms with the Rules. If a manufacturer fails to submit a sample or 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. Any sample submitted to the United States Golf Association becomes its property for reference purposes.
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 have some specific property, this means that it must be designed and manufactured with the intention of having that property. The finished club or part must have that property within manufacturing tolerances appropriate to the material used.

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. All parts of the club must be fixed so that the club is one unit, and it must have no external attachments except as otherwise permitted by the Rules.

Woods and irons must not be designed to be adjustable except for weight. Putters may be designed to be adjustable for weight and some other forms of adjustability are also permitted. All methods of adjustment permitted by the Rules require that:

(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. The disqualification penalty for purposely changing the playing characteristics of a club during a stipulated round (Rule 4-2a) applies to all clubs including a putter.

The overall length of the club must be at least 18 inches (457.2 mm) and, except for putters, must not exceed 48 inches (1,219.2 mm). 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.

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).

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).

The grip consists of material added to the shaft to enable the player to obtain a firm hold. The grip 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) For 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 length of the grip, and a slightly indented spiral is permitted on a wrapped grip or a replica of one.

The clubhead must be generally plain in shape. All parts must be rigid, structural in nature and functional. It is not practicable to define plain in shape precisely and comprehensively but features which are deemed to be in breach of this requirement and are therefore not permitted include:

• the face and the back (see Fig. VIII, dimension A); and on vertical lines between the horizontal projections of 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).

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. For traditionally shaped heads, these dimensions will be measured on horizontal lines between vertical projections of the outermost points of:

The material and construction of, or any treatment to, the face or clubhead must not have the effect at impact of a spring (test on file), or impart significantly more or less spin to the ball than a standard steel face, or have any other effect which would unduly influence the movement of the ball.

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. IX).

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.

The above specifications apply to clubs on which the impact area of the face is of metal or a material of similar hardness. They do not apply to clubs with faces made of other materials and whose loft angle is 24 degrees or less, but markings which could unduly influence the movement of the ball are prohibited. Clubs with this type of face and a loft angle exceeding 24 degrees may have grooves of maximum width 0.040 inches (1.02 mm) and maximum depth 1 1/2 times the groove width, but must otherwise conform to the markings specifications above.