This is point on the shaft where it is perfectly balanced from the tip section to the butt section. The balance point is typically indicated as a percentage and measured from the tip of the shaft. For example, a 46 inch shaft whose balance point is 23 inches from the tip has a balance point of 50%. Shafts that have more weight towards the tip will have a heavier swingweight when assembled. Shafts that have more weight towards the butt of the shafts are said to be a “counterbalanced shaft” and will have a lighter swingweight when assembled.
This is the section in the shaft located from the tip of the shaft where most of the forward bend occurs when a shaft recovers during the swing. If the shaft has a high bend point, the launch angle and resulting trajectory of the golf shot will be low. If the shaft has a low bend point, the launch angle and resulting trajectory of the golf shot will be high. This term is also known as the Kick Point. This term is being replaced by Trajectory or Launch characteristics. A High Trajectory or High Launch shaft will have a low Bend Point and visa versa.
Butt Diameter (Butt OD):
The outside diameter of the butt end of a shaft. The range is generally .580″ to .640″. Larger butt diameter shafts are found in stiffer and heavier shafts. The butt diameter will change the overall size of the grip so golfers must be careful to understand the size of the golf shaft in order to properly size their grips in a set.
This is a term used by MATRIX Shafts to describe the integrity in terms of flex when a shaft is rotated 360 degrees around its axis. A good shaft will have a high rating of CFI. See also Spine Index.
Cycles per Minute (CPM):
A way of measuring shaft stiffness at various points along the shaft. A shaft is put in a clamp of a certain length and the shaft is set in motion. The number of cycles per minute of shaft movement determines the stiffness of the shaft based upon the length of the clamp used, and the beam length of the shaft as it is tested. In general, the higher the CPM, the stiffer the shaft. It is very important to determine how the CPM readings were obtained as clamp sizes can vary from 2 1/2″ to 7 3/4″ and can be measured with clamps that allow for the grip to be on the shaft or just the bare shaft only. A longer length clamp will give a higher CPM rating, and a grip-on reading will be lower than a reading of just the bare shaft.
This is the stiffness of the shaft as measured in the first 15-20 inches of the butt section of the shaft. There are a variety of stiffness indicators that manufacturers use to designate the stiffness of their shafts. The most commonly used in the United States designates by letter code as follows: L=Ladies flex, A=Amateur or Senior Men’s flex, R=Regular Men’s flex, S=Stiff Men’s flex, and X= Extra Stiff Men’s flex. There are several other alphanumeric codes used to designated the butt stiffness of a shaft. OBAN uses numeric codes: 2=Senior Men’s, 3=Regular Men’s, 4=Stiff Men’s and 5=Extra Stiff Men’s. These designations are merely those given by the manufacturers and do not relate to each other. A method of measuring shaft stiffness is to test the CPM (cycles per minute) using a frequency meter in order to do a comparison of one shaft to another.
After-market shafts come in various lengths. A shaft designed for a driver or fairway wood is typically 46 inches long, but can be as long as 50 inches. These longer wood shafts are typically used in players competing in Long Drive events. Some shafts are designed specifically for fairway woods and are usually 44 inches in length. Hybrid shafts are 42-44 inches in length. Iron shafts come in two distinct varieties: Parallel tip shafts, which are usually designed to be tip trimmed for stiffness and butt trimmed to length, come in lengths from 40 to 43.5 inches. Taper tip shafts, which are designed for irons with tapered hosels, come in discrete lengths for each iron and vary from 35.5 inches to 40 inches. Wedge shafts are typically 35 to 37 inches and are usually taper tip.
Parallel Tipping Section (PTS):
Shafts that are designed with parallel tips have a tipping section that allows club builders to increase the playing butt stiffness of the shaft by trimming the tip. This is necessary as club head weights increase from driver though wedges so tipping the shaft enables the club builder to control the stiffness of the club he/she is building. The length of this section can be as little as 2 inches or as much as 11 inches depending upon the design of the shaft. This section of the shaft is parallel so it fits in a parallel hosel.
The location on the longitudinal axis of the shaft that is the stiffest as measured by either CPM or load. Every shaft will have a spine due to manufacturing tolerances and methods. The magnitude of a shaft’s spine and it’s affect on performance of the shaft when installed in a golf club is a matter of debate among golfers and clubmakers.
Tip OD (Outside Diameter):
The outside diameter of the tip section of the shaft which fits in the hosel of the club. Tip OD in modern clubs is either .335″, .350″, or .370″ for parallel tip shafts. Taper tip shafts are designated as .355″ but taper from that OD at the tip to .370″ just above the hosel. Taper tip shafts are specifically designed for certain irons and wedges.
This is the amount of torsional degrees of twist a shaft exhibits when a weight is placed a certain length away from the shaft on a beam attached to the shaft. This is measured in degrees of deflection and published as a number, i.e 2.8. Unfortunately, each shaft manufacturer may have a particular method of measuring torque so there is no consistent measure from one shaft to another. Torque can range from the low 1 degree to as high as 8 degrees. While a lot of discussion has been had around this term, torque is really about how a shaft feels to a player. Lower torque shafts will feel either more stable or “boardy” while higher torque shafts will feel less stable and more “whippy” at impact. Torque has very little to do with accuracy of shots.
This is the weight of the shaft at its raw length and is given in grams. When you see a number on a commercial shaft, that indicates the rough gram weight. A Grafalloy ProLaunch Blue SC 55 will weigh roughly 55 grams. An Aerotech Steelfiber i80 will weigh a little over 80 grams, and a Mitsubishi Rayon Kuro Kage Black Hybrid 100 will weigh in at 100 grams. Some shafts are designed to be constant weight so that, as shafts get shorter like in a set of irons, the shaft weights will stay the same. This can improve feel and performance for certain players.