You walk into a golf shop and admire the latest club offerings in the bags and on the wall. You check out the look of the clubs, you waggle the club, you take note of the price. Ever wonder how the club ever got to the shop in the first place? Where was it made? How was the club designed? What kind of metal makes up the head? All of these factors, and many others, are key elements in the design and production of a golf club head. When these elements are successful, an excellent performing, best selling club is produced; just how is that accomplished?

The vast majority of golf clubs made today - woods, irons and putters - are made through a process known as "lost wax investment casting." Basically this involves pouring (or investing) metal into a mold in order to produce a large quantity of heads that will have the same characteristics and specifications. Investment casting is used to make many other products in addition to golf clubs, some of which include auto and marine parts, medical equipment and other precision instruments. Most foundries that produce golf heads do exclusively that; their expertise is in the design, form and function of a golf club head.

Golf clubs start out as ideas in a club designer's head. The initial sketches might be done on a drawing table, paper napkin or on a cad-cam computer. From these first ideas, modifications are generally made and a model made of epoxy is produced. This model may be produced by hand or by computer, but is nearly always "tweaked" by the designer filing, sanding or grinding it until it is exactly as desired. Once a sample model is produced, it, along with the drawings detailing the specifications (loft, lie, weight, face angle, bounce, etc.) are sent to the foundry.

The foundry may be located here in the US, or it may be in Taiwan, China or Thailand. More and more companies, be they major OEM golf companies or component companies have their heads produced overseas. The main reason is a cost versus technology issue. The overseas technology is as good as it is here in the states, but the cost of producing a club in the Far East is less than half the cost of producing it here in the US. While there is a decided advantage in shipping time from domestic foundries, not to mention a language advantage, the lower costs of producing a head overseas outweighs these disadvantages. At least 90% of golf club heads made today are manufactured offshore.

Once the golf company chooses a foundry, the actual manufacturing process begins. From the drawings and/or models, the foundry creates a piece called a "brass master". Each golf club head in the set requires its own master. That is, there will be a master for the #1 iron, #2 iron, etc. (Keep in mind that woods, irons and putters will be made in the same manner.) This master will be an exact duplicate of the final club head, right down to the name, number, specs and scorelines. It is made by a combination of lathe, electro-etching machine and hand filing, sanding and grinding. Once the club head shape is correct, the name is engraved in the cavity and on the sole, the club number is etched on the sole and the scorelines are engraved in the face, following specific template patterns. The master goes through countless quality control checks prior to final approval; even the smallest flaw, in either grinding or specification in the master, will mean that every club head that is manufactured will have that exact same flaw. Creating a correct master is the key to successful investment casting.

Upon completion and approval by both the foundry and golf club company, the brass master is used to create an aluminum mold of the club head. The master is placed inside a cavity in between two pieces of aluminum or steel that form an enclosed shell. Liquid aluminum is then injected into the cavity, creating a negative image of the club head. When the aluminum cools and hardens, the brass master is removed. A perfect duplicate of the club head is now in the aluminum mold. The master is placed in storage at this point. The only time it will be used again is to create a new mold should the current one become somehow lost or damaged.

The next step in the casting process is wax injection. In this step, the closed aluminum mold is placed in a special machine that melts wax (This was is similar to paraffin wax) and injects it into the cavity of the mold. This creates another exact duplicate of the head, this time in wax. The waxes are carefully examined for any defects, and, once inspected, are affixed to a holder known as a "tree". This tree allows up to a dozen clubs to be cast at the same time. The wax tree is then coated with a ceramic slurry mix. Several layers of this mix are applied, with each layer being force dried at least overnight. The slurry hardens, forming what looks like a plaster cast when it dries. These dried slurry mixes are called "shells." When complete, the shells will be nearly 1/4" thick, providing much protection for the waxes inside.

Next the ceramic shells are heated, melting the wax from inside. The wax will be recycled for use in future mold injection. This initial heating and wax removal is the basis for the term "lost wax" casting. These resulting shells, which are now hollow, will be heated and will have molten metal, typically 431 or 17-4 stainless steel, poured into them to form actual cast club heads.

Before moving on in the casting process, a discussion of the various metals used in club heads deserves a mention. There are many types of steel that may be used in casting, 431 and 17-4 being the most common. 431 is a bit softer than 17-4; a higher nickel content makes the latter harder (stronger). 431 is used exclusively in irons and putters; it is not strong enough to make thin-walled metal heads. 17-4 is used in woods, irons and putters. There are few, if any, golfers who can actually tell the differences in metal hardness in golf clubs; differences are more psychological than in actual feel. The past couple of years have seen the evolution of other metals used to make metal wood heads. Among these which are harder and lighter than 17-4 are 15-5 stainless and  maraging steel, a mixture of any number of heat treated alloys that are stronger and lighter yet. Titanium has its place in casting as well, but it must be cast in a vacuum environment due to the nature of its molecular makeup. Its hardness is very similar to 17-4 stainless; the reason you see many jumbo ti woods is due to titanium's lighter weight and higher strength to weight ratio.

Next comes the procedure that defines investment casting. The now-empty shells are heated to temperatures approaching 1,000 degrees Celsius. The foundry term for this is obviously enough - "heat." The shells are turned upside down and molten steel (at 1,500-1,800 degrees) is poured inside. This process somewhat resembles a satanic ritual, complete with fire, smoke, and masked and goggled workers! The amount of heat generated by the casting process is tremendous; it is this high heat that permits the molten metal to penetrate to all of the inside areas of the ceramic shells. Immediately after metal pouring (investing), the ceramic shells, now containing actual metal club heads are set aside to cool for at least 24 hours.

Once cooled, the ceramic must be removed from around the club heads. A sledge hammer is hit against the trees, effectively breaking most of the ceramic away. It doesn't take much to break away the ceramic as it has been subjected to such high heat only a day or two ago. The heads are now cut away from the tree with chop saws.

They are next placed in large tumbling machines in order to remove any remaining ceramic from the scorelines and engravings. If these machines should fail to remove all of the ceramic material, a worker with a dental pick must pick away any remaining ceramic - a decidedly slow, tedious process. The clubs are then taken to a grinding machine, where the piece that held the club onto the tree is ground off to match the contour of the club head. This step is the only place where the club actually touches any type of grinding or sanding machine; the fact that all of the clubs are made from one mold eliminates virtually all hand shaping of the heads, adding to product consistency and decreased labor and machine costs.

The heads are now the proper shape, but two key steps are yet to be performed. The hosels of the clubs are precision drilled utilizing a holding vise designed specifically for each head. This ensures accuracy of hosel size and depth. A club drilled on a standard drill press could have substantial hosel bore differences, effectively making the finished clubs play quite differently than designed. The final step prior to a finish being applied to the head is that of a check/adjustment of any loft or lie variances of each head as compared to the desired spec. When working with metal heads, the soleplate, which is cast as one piece, and the top part of the metal wood, known as the "topshell", are welded together. If a wood was cast in one piece like an iron, it would weigh too much as the inside of it would be solid steel. Minimal specification alterations are usually necessary for any cast club head due to the consistent nature of casting, but as quality control is important in making a top-notch product, all heads go through this check/adjustment step.

At this point in the casting process, we have a club head in which all specs are correct, but the club is most likely a dark gray-blackish color. The cast iron heads will be either polished on a series of belts or will be placed in a large tumbler for finishing. It is here that woods may undergo another step that differentiates them from irons. Some woods are foam-filled. That is, they are injected with an "insulation type" foam that is designed to help the club achieve a desired weight or to help the club dampen vibration and sound. Larger heads are not foamed as this would most likely add excessive weight to the heads. 

Regardless of foam-filled or foamless, the wood heads will either be painted or tumbled. Many times a urethane finish will be applied as a protective coating, adding a gloss finish to the head. If the heads are irons or woods that require a tumble finish, the heads will be placed in an open tumbler amidst various types of tumbling stones, or "media." A solution is often mixed with the media to create one certain type of tumble finish as compared with another. The amount of time in the tumbler also has an influence on the final finish as well. A head that is finished in this manner is labeled as a "tumble finished" head. Ping irons and Callaway woods (These also have a urethane coating.) are probably the most common examples of tumble finished heads.

If an iron is not tumbled, it is either stain finished or high polished. Skilled technicians use a series of belts on machines similar to belt sanders to create these finishes. Depending upon the grit and speed of the belts a satin finish, which looks much like brushed aluminum, or a high polish finish, which looks shiny like chrome, is imparted to the head. Satin and high polish are not used on the top of metal wood heads as it is very difficult to use belts on the curving surface without creating visual waves in the finish; thus satin and polish are used on the soles of metal woods only. A metal wood may receive a painted finish. Painted finishes are applied in the same manner as a finish is applied to your car. Such finishes are not used on irons due to the fact that they are not as wear resistant. Putters may be finished in any of the three manners, tumble, satin or high polish.

The iron heads now need to be masked, as typically the cavities of the heads and the faces are either painted or sandblasted. In any event, the surfaces not to be further finished are masked with strong vinyl tape and the cavities and faces receive their required finishes. All heads, be they woods or irons, are given a close cosmetic inspection; any heads not meeting requirements are rejected and will not be sold. Paintfill is the final step in the making of a head. The engravings are filled with the appropriate color paint, either through the use of a hypodermic needle filled with the paint or by applying paint with a brush and wiping away the excess with a towel. The heads are now inspected one more time for cosmetics, a spot check of head specifications is completed and the heads are packaged for shipment to the golf club manufacturer for whom they were produced.

The investment casting process is complete. From drawing to model, from master to mold, from wax to metal, from unfinished to brand new heads, the lost wax investment casting process is used to produce over 90% of the golf club heads in play today - that's several million heads each year. The entire process takes close to six months, not counting and research and development or hit testing that may take place between first head samples and final production. That means that next year's hottest new deign may very well have been someone's club head design doodle on a napkin at last year's New Year's party... In other words, what may be the 21^st Century's hottest design may already be in progress, only time and investment casting will tell.