The Story of Repair 2 From the Steel Shaft to the Carbon Shaft
When Wakasugi first joined the company in the mid 1970s, Honma made a shift from the steel shaft to the carbon shaft as its main shaft type.
As the name indicates, the steel shaft is made of steel “HAGANE”. When the shaft was replaced, the hosel was heated to a certain point, and the bond melted without the shaft changing shape. This meant that the steel shaft could be taken out and replaced numerous times―and therefore that it could be re-used. In the mid 70s, on the day that the first carbon shaft was manufactured at the Tsurumi Plant, Wakasugi and the other members of the repair team witnessed the first carbon shaft persimmon wood right before their eyes. The task assigned to Wakasugi was how to remove the carbon shaft without damaging the persimmon wood. If this wasn’t possible, then neither repairs nor re-shafting would be possible. This was the one condition that had to be cleared in order to commercialize the product.
The carbon fibers comprising the shaft were fiber made of charcoal which, in contrast to steel, was not very heat-resistant. In addition, the plastic covering the carbon also melted under heat. It was therefore impossible to heat the material in order to extract it in the way it had been done with steel. First, Wakasugi simply cut the shaft from the head.
What was left of the persimmon head was the hole for the shaft and the hollow carbon shaft that lined inside. Wakasugi and his team heated a steel pole the thickness of the hole until it was bright red, and shoved the pole into the hole. The bond and the plastic melted, while the carbon got scorched. What was left of the shaft shrank and changed shape.
Leaving the steel pole inside, the hole in the persimmon began to smell of burnt wood. If the persimmon was scorched, there was no way to commercialize the product. Doing it just right was a difficult thing. At the end of a trial-and-error process, we realized that quickly inserting the burning pole in the hole three times resulted in just the right level of change in shaft shape.
Next, we had to figure out how to release the persimmon head from the shaft without damaging it. Taking the end of the shaft which had flown out of the hole and placing it in a vice, we pulled it out holding the head in both hands. If it was not pulled out all at once, the shaft would be broken in the neck, leaving some of it inside. However, if we pulled too hard the head would split. The process of replacing the shaft, which had been relatively easy when they were made of steel, suddenly became a skill requiring highly sophisticated technique.
There were fewer than 10 repair engineers at the Tsurumi Plant at the time, and from then on they would be in change of replacing the old shafts with the carbon shafts, which will later be hugely popular. The time required for each club was more than double that for steel clubs. Including overhaul and loft adjustment, the entire team could handle only 20-30 clubs daily. The repair room operated overtime day after day.