Golf technology up close

Materials World magazine
1 Aug 2014
Miura’s nickel chrome wedge

Avid golfers will know if their clubs are cast or forged, the flex of their shafts and the story at the core of every ball. Eoin Redahan investigates the materials and designs behind the obsession. 

When I was a youngster, I spent thousands of hours putting a small ball into a slightly bigger hole with an array of tools. Like my peers, it didn’t take long for me to become uppity about golf’s equipment. I quickly disregarded archaic drivers made from wood. Even steel heads, for the most part, were dismissed. It was all about having a titanium-headed driver. I believed the marketing hype. I wanted one because I was told it would help me hit the ball farther. I also coveted graphite shafts instead of stainless steel ones because they were lighter. The lighter shafts helped me swing the club faster and, you guessed it, hit the ball farther. It was middle class machismo in slacks and collared t-shirts.

I was also easy prey to the material fads that swept the more delicate parts of the game – chipping and putting. There was this rusty wedge that promised greater spin control for those tricky finesse shots around the green. The clubhead’s finish was left to corrode to provide extra friction which, in theory, allowed players to spin the ball to a stop as it neared hole. Let’s not forget – the ability to spin the ball is second only to length off the tee in the machismo stakes.

Even putting wasn’t exempt from the material infatuation. My peers and I were hyper-aware of clubface materials for the game’s shortest shots of all. We deliberated over facing materials that would suit our style. If greens were particularly fast, we wanted a putter with a softer rubber insert so the ball would roll less speedily. We worried about sand- and clay-based greens and the direction the grass grew in relation to the sun.

We had crossed into a green-tinted otherworld complete with peculiar words and oppressive etiquette. A place where children spoke of balata rubber and the old spoke of hickory-shafted clubs. Of course, few of these people knew much about materials, apart from how they helped lower their scores.

Even now, 20 years later, nothing has changed. Golf is still a sport preoccupied by materials and manufacturing processes. But what equipment obsesses these otherworldly creatures now?  

Putter grips
Golfing infidels must wince at the mention of a putting grip evolution. How could the grip of a putter possibly become more advanced?

It turns out, quite a lot can be done. While many grips will look the same to the Joe Bloggs eye, there is a lot of research involved in improving performance. For example, SuperStroke’s polyurethane grips feature a crosstraction design to wick away the moisture from sweaty hands.

The company has also re-thought grip design. Jon Luna, SuperStroke USA’s Marketing Director explains, ‘Traditionally, grips taper quite a bit from butt to tip. This means the lower hand has to squeeze more to get around the smaller surface. Our grips, being parallel, make sure both hands do the same amount of work.’

One difficult aspect of putting – slotting the ball into the hole – is to quieten the twitchy little muscles in the hands. One way of achieving this is to add weight to the grip. Luna says, ‘It is easier for a player to control more weight in the hands than it is to control less. There are two things that successfully make players more consistent putters – adding more weight and making the grip larger.’

To this end, SuperStroke has created an extra large grip with an adjustable weight plug at the butt end, whereby golfers can add an extra 5g, 15g or 30g.

What are your golf grips made from?
Golf grips are made from a range of materials including leather, rubber and thermoplastics. In olden days, leather grips were wrapped around the shaft. Nowadays, grips comprise one-piece sleeves that are pulled onto the shaft and held in place using a long-cure adhesive.  

Imagine swiping an apple from a tree branch, first using a bat made from lead and then another of bamboo. You will find the bamboo bat can be swung more quickly, but the lead version will be more accurate. Ideally, you would swing a bat with the attributes of both materials. Similarly, club shaft manufacturers are looking to develop materials with greater stiffness for accuracy and lighter weight for added swing speed. In recent years, shafts were made from relatively stiff stainless steel or lighter, whippier graphite alternatives.

Alex Dee, Vice President of Fujikura Composites America, explains that shaft materials can now combine these coveted attributes. ‘Materials have come a long way. Carbon fibres with greater stiffness, strength and elongation and filming technologies have allowed us to use ultra-low resin contents for lighter shafts with the stiffness and strength of heavier designs.’

To do this, Fujikura has devised a cage-like construction that surrounds the graphite shaft fibres of the outer walls. This rigid structure means that lighter, thinner walls can be made with the same feel of a heavier shaft. The company also uses Triax – a honeycomb-structured material made by weaving carbon-fibre in three directions – to provide stability without adding weight.

To create maximum swing speed and accuracy, different parts of the shaft need to work in various ways. Dee explains, ‘We want butt and middle stiffness to allow bending during the downswing that is large enough to store potential energy, but not too large to make the club feel loose. Going into impact, we want the tip and middle stiffness to promote a forward kick, but we also want the tip stiffness firm enough to position the clubhead at an optimum orientation to achieve proper launch conditions.’  

The wedge
For a game of such technical rigour, it is unusual to hear golfers mention the word feel so often. Manufacturers will tell you that some players prefer forged irons to cast irons because the softer metals used in the forging process are more pleasing to the finger.

Adam Barr, President of Miura Golf, says, ‘A forged golf club transmits more information to the player’s hands and body because it conducts a truer set of frequencies – that is, it vibrates more pleasingly at impact. There is a quality to a well-struck shot that players can identify immediately but find hard to describe. It’s like they’re discussing wine. You hear “soft” and “buttery” and “solid but not clanky”. Unlike casting, forged clubs can be made more effectively with a fine, uniform grain structure, free of the piping and voids that can create bad vibrations.’

Arguably, an area where tactile feedback is at its most important is in wedge play, which includes deft chip shots from heavy grass, bare lies and sand. These shots, which are at various distances within 120 metres of the green, require subtle spin- and trajectory control.
But even within the forging gamut, the choice of material is important. Miura uses steel in various combinations with low levels of carbon and trace elements for the forging process. ‘We create a density of molecules more akin to a jar of sand than a jar of marbles,’ Barr notes. ‘If you pack marbles closely together, they will still have some space between them because of their very structure. Grains of sand, being smaller and firmer, have less useless space between them.’

However, even if you have the butteriest wedge in town, there are certain design elements the club must include for it to function properly. If you look closely at the sole of a club, you will notice how it curves as it sits on the ground. This curving is called camber. Barr explains, ‘Rarely will you see a club whose sole is completely flat. This design element allows a player to stand beside the ball and hit it cleanly. If there were no such camber, the corners of the clubhead would catch the turf, pushing or pulling the ball off line.’  

The driver
The driver is the longest club in the bag with the steepest loft, making it the hardest to hit. When hit well, however, it goes farther than any other club in the bag. The driver originally had a large wooden head (it is sometimes still referred to as a 1-Wood), but the latest models tend to be made from titanium, as it combines light weight with high strength.
While the abiding objective of driver R&D is to create a club that clatters the ball as far as possible, many recent efforts have focused on reducing the sidespin that sends balls careening off line like badly flung frisbees. Several manufacturers, including Callaway, have introduced adjustable perimeter weighting technology to mitigate bad shots.

This system involves sliding a weight to different parts of the clubhead to encourage different shapes of shot. So, if you are afflicted with an uncontrollable slice, you can compensate by sliding the weight towards the heel of the club to affect a draw – a shape of shot that spins the other way. The net effect, theoretically, is a straighter shot.

Irons are generally used for shots of less than180 metres (or 230 metres for elite golfers). The latest technology for these clubs focuses on encouraging a consistent strike and healthy launch angle. To do this, manufacturers use perimeter weighting to stabilise the clubhead at impact, and design irons with more weight at the back and bottom of the clubhead to create a better launch angle.

Irons tend to be cast rather than forged, using stainless steel and a smattering of other metals such as chromium, nickel or tungsten. Casting is preferred as it allows manufacturers to create a greater range of design features. Sadly, these design elements fall victim to the worst marketing speak. That means your average duffer will play with Speed Pockets, Variable Muscle Bulge technology and RocketBladez.

The golf ball

The pearly white, dimpled golf ball is unrecognisable from its predecessors. The first balls were made from hard woods (such as beech), before graduating to semispherical leather pouches filled with goose feathers.

Today’s golf balls combine materials such as polyurethane and urethane with rubber-based materials. Several hundred dimples grace the surface to make the ball more aerodynamic. Cranky former champions bemoan the spectacular development of the ball. In their day, a ball was engineered to give you maximum distance or maximum spin control, but never both.
Multilayer golf balls can fulfil both criteria, while reducing pesky sidespin. This was achieved by understanding the impact angles of different clubs. Flatter shots with less-lofted clubs (such as the driver) compress the ball right to its firmer core for maximum distance, whereas shots with more lofted clubs (used nearer the green) tend to hit the ball at a far steeper angle. The club abrades the softer covering without striking the ball’s core, resulting in a softerlanding shot with more spin.  

As of 1 January 2016, the professional golfer will be banned from jamming the end of the putter into the belly button or anchoring it in the armpit’s nape. Every now and again, the golfing gods implement rule changes to uphold the spirit of the game. Essentially, this means scuttling technologies that make the game significantly easier. And so, after several players won golf’s biggest prizes in a short space of time using anchored putters – broom-handle and belly putters – the game’s governing bodies decided to outlaw anchoring.

In the wake of this ruling, counterbalanced putters have become more popular, as they promote a heavy pendulous stroke, much like their outlawed brethren. Bettinardi Golf makes its counterbalanced putters by lengthening the putter shaft by 7.6cm and adding 45g to the putter head. Sam Bettinardi explains, ‘People are looking for alternatives to the anchored putting stroke, and the counterbalance method is a great way to promote a smooth, stable stroke. The extra length on the putter adds weight, and the weight in the head counterbalances this.’

Bettinardi Golf uses various other methods to help twitchy golfers hole out with minimum anguish. Perimeter weighting is used to keep the putter head steady for a longer period of time, and honeycomb milling is used to optimise the actual strike. He notes, ‘We found that that by milling the face on a horizontal computer numerical control machine, the face of the putter becomes flatter than the typical milled face. We use a different tool to remove around 55% of the material from the face of the putter, which provides a soft feel at impact.’

It is easy to understand why you would need the flattest surface possible for putting, but why focus efforts on a soft face? ‘Golf balls are becoming harder so players can hit the ball farther,’ says Bettinardi. ‘We offset this by using the softest metal, which is carbon steel, before milling the face to produce the best response possible.’  

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