Appendix II, 1a provides that:
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.
In defining what is meant by the term "club," this Rule makes reference to the three main forms a club traditionally takes, i.e., woods, irons and putters. The terms "wood" and "iron" do not necessarily refer to the material the club is made out of, but rather to the general shape of the clubhead. A "wood" club is one where the head is relatively broad from face to back, and it can be made of materials such as titanium, steel or wood. An "iron" club is one where the head is relatively narrow from face to back, and it is usually made of steel.
By definition, the loft of a putter must not exceed 10 degrees, and a club with a loft greater than that is normally regarded as an iron club. Putters are permitted to have negative loft. However, a loft of less than -15 degrees would not be considered "traditional and customary in form and make" (See Design of Clubs, Section 1a(i)).
The Rules and guidelines sometimes distinguish between "wood" and "iron" clubs (see Design of Clubs, Section 5c for an example of where they do). As hybrid, rescue and utility clubs have increased in popularity and design variety, it is sometimes challenging to define whether a particular club should be classified as a wood or an iron. In such cases, the general shape and size of the clubhead should be referenced in order to determine which classification should apply for the purpose of applying the rules. Additionally, there are various instances throughout the Rules where different specifications apply to putters. These differences in the Rules will be highlighted appropriately throughout this Guide.
As a consequence of these differences, confusion often exists as to which rules apply to "chippers," i.e., iron clubs which are specifically designed to be used just off the putting green with a putting stroke. For clarification on "The Status of a Chipper," see Decision 4-1/3 in "Decisions on the Rules of Golf" and Design of Clubs, Section 1c.
Appendix II, 1a goes on to state that:
The club must not be substantially different from the traditionally 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 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.
In explaining this part of the Rule, it is easier to divide it into the following four sections:
(i) Traditional and Customary Form and Make
The phrase "traditional and customary form and make" does not mean that clubs must look the same as they did 100 years ago. If so, steel shafts and metal woodheads would not conform to the Rules. As noted in the introduction to this Guide, it is not the purpose of the Rules to stifle innovation.
In practice, the "Traditional and Customary Rule" is rarely used - having been largely superseded by the "Plain in Shape" Rule (see Design of Clubs, Section 4a). However, it is still applied in those cases where the Equipment Standards Committee decides that a particular design deviates from traditional appearance and/or construction standards, but which may not be covered by a more specific provision within the Rules.
(ii) Club Composition
The purpose of this provision is merely to stipulate that multiple shafts and heads are not permitted. It also highlights that it is not necessary for a club to have material added to the shaft for gripping. For further information regarding a club which has no material added to the shaft to form a grip, see Design of Clubs, Section 3.
(iii) All Parts Must Be Fixed
This is interpreted to mean that no part of the golf club should be designed to move, nor should it be promoted as doing so. Therefore, if any part of a club were to incorporate moving powder, pellets, liquid, vibrating wires, rollers, tuning forks, or any number of other features which could be considered a "moving part," it would be in breach of this Rule. Additionally, this provision is interpreted to mean that with some exceptions, when assembled, all parts are bonded such that they require heating to loosen. Of course, this does not apply to clubs with permitted adjustable features.
(iv) External Attachments
In 2008, the USGA amended the wording of the provision relating to external attachments in order to accommodate a change in interpretation, which previously prohibited any "external attachments" to the club (with certain specific exceptions). While the Rule continues to prohibit the attachment of anything to the club which could potentially have an effect on its performance (e.g., aiming bars or weights), other items may now be permitted to be attached to certain parts of the club provided (a) no performance benefit can be derived, and (b) no other Rules are breached, including Rule 14-3 (Artificial Devices, Unusual Equipment and Unusual Use of Equipment).
Prior to 2008, two notable exceptions to this Rule included the permission to apply lead tape to the shaft or clubhead for weighting (see also Design of Clubs, Section 1b and Decision 4-1/4 in "Decisions on the Rules of Golf") and the use of a suction cup at the end of the shaft of a putter to assist with retrieving the ball from the hole. Even though these exceptions may be considered counter to the provisions in this guideline, use of these items will continue to be permitted on traditional grounds.
The change in wording reflects a broadening of the types of items which may be attached to an existing club, provided the items meet the given criteria:
Temporary, non-permanent attachments to the shaft, such as decals for identification or tape to protect the shaft (also permitted prior to 2008). Such attachments, for identification only, may also be permitted on the clubhead, other than the face. However, such attachments must not serve any other purpose, such as for alignment. In the case of driving clubs, such attachments must not be applied in a manner that would cause any confusion with the correct identification of a driving club on the List of Conforming Driver Heads. In other words, any such attachments must be subtle, plain in appearance and discreetly positioned.
Temporary, non-permanent attachments to the shaft, such as clip-on devices, provided such items do not excessively protrude from the shaft, their cross-section conforms to the shape of the shaft, and are sufficiently fixed. Other clip-on devices that do not conform to the shape of the shaft, such as a club prop for use in wet weather, may be attached to the shaft provided such devices are removed prior to making a stroke.
Temporary, non-permanent attachments to the butt end of the grip, such as tee pegs, ball markers or ball retrieval devices:
provided such items do not cause the grip to be considered molded for the hands or create a bulge or waist in the grip; and
the outer diameter of such an item is less than or equal to the outer diameter of the butt end of the grip and the item does not extend beyond the butt end of the grip by more than 2 inches (50.8 mm).
other temporary, non-permanent attachments to any part of the grip, other than the butt end, provided such items are removed prior to making a stroke. However, tape or gauze applied to the full length of the grip is permitted, provided the grip conforms in its modified state.
Other material added to the shaft, such as for alignment purposes, provided the material is considered semi-permanent. "Semi-permanent" is interpreted to mean durable and not easily removable. Additionally, it must not be re-usable and/or must be essentially destroyed upon removal. However, such application must not breach Rule 14-3.
Attachments to the clubhead (other than the face), such as protective coverings, decorative items or alignment aids, provided the item is semi-permanent. However, such items must not excessively protrude from the clubhead and must conform to the shape of the clubhead. Additionally, for driving clubs, such attachments must not serve to cause any confusion with the correct identification of a driving club on the List of Conforming Driver Heads. Permanent additions to a clubhead are considered a part of the head and, therefore, the head, in its modified state, would have to conform to the Rules of Golf, particularly the requirements of Rule 4a, Appendix II (i.e., ‘plain in shape' and dimensions).
Appendix II, 1b provides that:
All clubs may incorporate features 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).
In order to preserve the integrity of Rule 4-2 (Playing Characteristics Changed), this Rule clearly states that it must not be too easy for a player to make adjustments during the course of a stipulated round. This is interpreted to mean that adjustments must require the use of a special tool, such as an Allen key, a Phillips screwdriver or a custom-made tool or device. It must not be possible to make the adjustment just by using the fingers, or some other object which would normally be kept in a golfer's pocket, such as a coin or a pitch-mark repair tool.
The above restrictions have been included in the Rules in order to encourage the player to make all of the necessary adjustments to his clubs before starting his round, and to protect him from either unwittingly or purposely making adjustments during a round.
(ii) Adjustability for Weight
All clubs may be designed to be adjustable for weight, provided the adjustment mechanism conforms to the conditions described previously and in Appendix II, 1b of the Rules. An example of what would and would not be permitted is illustrated below.
As noted in Design of Clubs, Section 1a, with respect to adjustments for weight, the only exception to the conditions described in (i) above is the addition or removal of lead tape. This is a practice which pre-dates the introduction of the adjustability rules and is permitted on "traditional" grounds. The addition or removal of lead tape during a round is not permitted (see Rule 4-2a and Decision 4-2/0.5 in "Decisions on the Rules of Golf").
(iii) Other Kinds of Adjustability
In 2008, the USGA relaxed the Rules regarding adjustability to allow all clubs, including woods and irons, to be designed to be adjustable in ways other than for weight. However, such adjustment features are subject to evaluation by the USGA, and manufacturers are encouraged to submit all adjustable design innovations to the USGA in the early stages of development.
Examples of other forms of adjustability include a putter designed to be adjustable for lie and/or length. Additionally, while some head/shaft assembly systems have been evaluated by the USGA and found to conform to the Rules of Golf, not all systems are considered conforming. Please consult the USGA to determine which systems conform to the Rules. Again, all permissible methods of adjustment must require the use of a special tool, not just the fingers or a coin, etc. If, as is often the case, a screw is used to fix the adjustable mechanism, the club must, for all practicable purposes, be unusable without the screw being in place and tightly fixed. As an exception to this unusable requirement, the USGA has permitted the long putter which can be dismantled into two shorter lengths for travel purposes. A screw-together ("pool-cue") joint is permitted with an Allen screw, or something similar, that penetrates the threaded section of the joint by at least halfway.
When assessing the conformity of an adjustable club, it is important to remember the third condition listed in Appendix II, 1b, and to ensure that the club cannot be adjusted into a position which does not conform to the Rules. For example, a putter which is adjustable for lie must not be capable of being adjusted into a position where the shaft diverges from the vertical by less than ten degrees (see Appendix II, 1d and Design of Clubs, Section 1d), or any other position which would render the club non-conforming.
Appendix II, 1c provides that:
The overall length of the club must be at least 18 inches (0.457 m) and, except for putters, must not exceed 48 inches (1.219 m).
This Rule is straightforward, and the measurement of woods and irons is well described and illustrated in both the Rules and the of Golf." The measurement of length for putters can be illustrated as follows:
Please note that the Equipment Standards Committee has adopted a position that clubs designed for chipping, including modified wedges, that are longer than standard-length clubs of similar loft are not traditional and customary in form and make (see Appendix II, 1a). The following table is used for the purpose of determining the maximum allowable length of a chipping club.
Minimum Loft (°) 16 20 23 26 29 33 37 41 45
Maximum Loft (°) 19 22 25 28 32 36 40 44 48
Maximum Allowable Length (in) 41.5 41 40.5 40 39.5 39 38.5 38 37.5
Maximum Allowable Length (m) 1.054 1.041 1.029 1.016 1.003 0.991 0.978 0.965 0.953
Appendix II, 1d provides that:
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. 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.
This Rule is particularly relevant to putters, and it exists mainly as a means for disallowing croquet or vertical-pendulum style putters (with vertical shafts) and shuffle-board style strokes, as well as designs which facilitate such strokes (see Figure 4).
For most putters, the "normal address position" is determined by the geometry of the head. The head would be placed on a horizontal flat surface, with the sole touching that surface at a point directly below the center of the face. The shaft angle is measured with the head in this position (see Figure 5).
If the putter head shape or weight distribution is very asymmetric, it may be necessary to make a subjective judgment as to where the effective center of the face is, and then to sole the club directly below that point. The position of the head in this instance may not always be the position that was intended by design. Nonetheless, in some cases, a judgment must be made based on how the club could feasibly and effectively be used (see Figure 6).
The same subjectivity may also be needed when confronted with a putter which has a very curved sole (see Figure 7). As before, the Equipment Standards Committee takes into account not only the manner in which the putter is designed to be used, but also the way it could feasibly and effectively be used, given the geometry of the head as well as other unique characteristics of the overall design. This interpretation is particularly relevant to long-shafted putters with very curved or multi-planed soles - however, standard-length putters of approximately 34 to 38 inches may also be subjected to this assessment.
It should be noted that all putters can usually be positioned in such a way that the shaft diverges from the vertical by less than 10 degrees or even to a position where the shaft itself is vertical. Also, it is unusual for the sole of a putter to be completely flat all the way from heel to toe. When faced with a ruling of this kind, the decision should not be based on whether a player uses the putter with the shaft in a position of less than 10 degrees - but whether the putter design facilitates a player placing the shaft in a position of less than 10 degrees (see Figure 8).
If the overall design of a putter is such that the player can achieve a "vertical-pendulum" style stroke (i.e., putt effectively with the shaft in a vertical or near-vertical position), it would be ruled contrary to Appendix II, 1d, even if the shaft angle does satisfy the 10-degree Rule when the putter is in its "normal address position." The shaft angle on such a putter could be required to be increased to as much as 25 degrees. In assessing whether a putter can be used effectively in a "vertical-pendulum" style manner, the combination of the following features should be considered:
length of shaft
position of shaft attachment to head
angle of shaft in toe-to-heel plane and front-to-back plane
shape and weight distribution of head
curvature and shape of sole
intent of the design
Even though each of these putter features, when considered separately, could conform to the Rules, the combination of the features might lead to a decision that the putter does not conform.
This is an extremely good example of an area where rules officials should take care not to make a decision unless they are 100% certain they are correct. If, after examining the club and carrying out all of the appropriate consultations, it is still not possible to give a definitive ruling, a Duration of Competition or Duration of Round Answer should be given (see Field Procedures - Guidance to Rules Officials Concerning Questions on the Conformity of Clubs at Competitions).
The determination of a feasible "normal address position" or whether a putter can be used with the shaft in a vertical or close-to-vertical position can be highly subjective and, in terms of those putters actually submitted to the USGA, the job of making rulings is easier because it is possible to compare them with previous submissions and decisions.
Appendix II, 1d goes on to state that:
Except for putters, all of the heel portion of the club must lie within 0.625 inches (15.58 mm) of the plane containing the axis of the straight part of the shaft and the intended (horizontal) line of play.
The intent of this rule is to prevent center shafted clubs (see Design of Clubs, Section 2c - Attachment to the Clubhead). The measurement is illustrated in Figure 9. For unusually shaped heads (e.g., square driver heads), the outermost point on the heel may be located at a point significantly back from the face. As such, the measurement would be completed at that point.
As provided in the Rule, in most cases, the shaft of a putter may be attached at any point on the clubhead (see Section 2c).