golf

 

Club heads

drawing of club heads showing angle called lieLie

Lie is the angle between the shaft and the ground. Lie is called “upright” if the shaft is more vertical than usual; “flat” if less; the range of variation is about ±2°. A lie that is too great for the player can result in shots to the left of the target; if the lie is too flat for the player, shots may go to the right.

drawing of club heads showing angle called loftLoft

is the angle between the face of the club and the vertical. A player with a low handicap will probably prefer several degrees less loft in a driver than the average golfer.

Face angle

Loft describes the vertical tilt of the club face; face angle describes a horizontal tilt in woods.
If the face “faces” straight ahead; the face angle is zero, or square.
If it faces left; it is “open”.
If it faces away from the golfer, it is “closed” (or “hooked”).

To a person addressing the ball, the face appears to be about 2° more hooked than it really is.

Face bulge, face roll

The face of a wood is curved in two directions, like the surface on the rim of a doughnut. The amount of curvature is described by two radiuses. Face bulge is measured in a horizontal plane and face roll in a vertical plane. Values are from 7 inches to 20 inches in steps of ½ inch; a typical value for a #1 wood is 9½ or 10 inches.

A physicist has done a mathematical analysis of the effect of this curve, and concludes that the curve tends to drive the ball in the opposite direction from the curvature due to the ball's spin, which comes from hitting it offcenter. As a result, the ball is more likely to go straight. He also concluded that golfers who hit the ball hard benefit from a more deeply curved head.

A. Raymond Penner.
The physics of golf: The convex face of a driver.
American Journal of Physics, volume 69, page 1073 (October 2001).

Offset

In some clubs the shaft is ahead of the head; the hosel curves back to meet the head.

Grooves

USGA rules regulate the size of grooves on the club face. They may be no deeper than 0.020 inch and no wider than 0.035 inch, and the flat area between grooves must be at least three times the groove width or 0.075 inch, whichever is smaller.

The following tables give some idea of the ranges of values these parameters can take in a set of clubs. These are not ideal values; that depends on the player and his or her game. Golf pros and club shops are happy to take measurements, analyze swings, and make recommendations.

Woods

#1 #2 #3 #4 #5 #6 #7 #8 #9 #11

Loft

9°–12° 14° 15°–17° 20° 21°–24° 24° 26° 29° 32° 35°

Lie

Flat

53°   54°   55°          

Std.

55° 54° 56° 56° 57° 56° 58° 58.5° 59° 60°

Up.

57°   58°   59°          
Face Angle +1°   +1°   +1°   +1° ±1° ±1° ±1°

Typ. head weight (grams)

200   210   220   228 231 240 240

 

Metal Woods #1 #2 spoon #3 #4 #5 #7 #8 #9 #11
Loft

Flat

12°–13°   16° 19° 22° 25°–26° 29° 32° 35°

Std.

10° 12° 13°              

Deep

12° 13°         28°      
Lie

Flat

53°     54°   55°        

Std.

55°     56° 56.5° 57° 58° 58.5° 59° 60°

Up.

57°     58°   59°        
Face Angle +1°–2° +1° +1° +1.5° +1° +2° +2° ±1° ±1° ±1°
Typ. wt* (grams) 202     210   220 228 231 240 240

Metal woods are also made in another sequence of sizes which are about 25 grams heavier in each size.

 

Irons #1 #2 #3 #4 #5 #6 #7 #8 #9 pitch wedge sand wedge*
Loft 16°–
17°
18°–
20°
21°–
24°
24°–
27°
28°–
31°
32°–
35°
36°–
39°
40°–
43°
44°–
47°
48°–
51°
54°–
56°
Lie Flat 54° 55° 56° 57° 58° 59° 60° 61° 62° 62° 62°
Std. 56° 57° 58° 59° 60° 61° 62° 63° 64° 64° 64°
Up. 58° 59° 60° 61° 62° 63° 64° 65° 66° 66° 66°
Offset 5 4.5 4 3.5 3 2.5 2 1.5 1 1 .5
Weight (g) 229 236 243 250 257 264 271 278 285 292 304

*Beyond the sand wedge lie other irons, often called lob wedges, with lofts of 60° or 64°.

Golf club shafts

Flex

From most flexible to most rigid, the grades are L (ladies or light), A (average), R (regular), (some makers add F, firm, after R), S (stiff), and XS (extra stiff). The more powerful the player, the stiffer the required shaft.

Tip diameter

Shafts for woods have diameters of 0.270", 0.277", 0.286", 0.294", and 0.320", all of which are tapered, and a 0.335" parallel tip. For irons, shafts are available in a 0.355" taper tip and a 0.370" parallel tip.

Butt diameter

From 0.560 inch to 0.620 inch in 0.020 inch increments, and also 0.700".

Grip

Grips are sized by shaft diameters. Those for shafts with smaller diameters have thicker walls than those for thicker shafts, so that each shaft plus its matching grip comes out the standard size. If a grip is installed on a shaft larger than it was intended for, its installed diameter will be oversize. The club maker can also enlarge the grip by wrapping the shaft with masking tape before installing the grip. A very small increase–¹⁄32 or even ¹⁄64 inch–can make a difference. A grip that is too large can cause a player to slice; too small, to hook. Special grips are available for players with arthritis.

Swingweight

Total weight is important, but so is how the weight is distributed over the length of head and shaft. Swingweight describes this distribution. Two swingweight systems are in use, one using a fulcrum 12 inches from the butt of the shaft, and the other with the fulcrum at 14 inches.

Golf balls

The maximum weight is 1.62 ounces. In the United States, the minimum diameter is 1.68 inches; but under the rules of the Royal and Ancient Golf Club of St. Andrews, Scotland, which apply in much of the world, the minimum diameter is 1.62 inches.

Golf tees

The standard tee is 2 ¹⁄8 inches (5.4 cm) long.  158 inch, 1 78 inch and 2¾ inch tees are also made.

The hole

The hole is 4¼ inches (10.8 cm) in diameter and at least 4 inches (10.2 cm) deep. If it is lined, the uppermost part of the liner must be at least 1 inch below the surface of the putting green.

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