We don’t know too much about Antonio Stradivari, but we do know that he first sat down at a workbench as a journeyman luthier sometime in the mid-1600s. By around 1680, Stradivari had built a reputation as one of the world’s premier designers of musical instruments – not just violins, but guitars, violas, cellos and harps.
And while the techniques Stradivari used in his masterpieces may never be replicated, the basic methods of instrument-making have remained relatively consistent over time. This is particularly true of violin bows, which are still made of wood and horsehair. When horsehair is used in the manufacture of violin bows, it is called bow hair.
The choice of material for the bow’s handle is important. Though some designers use synthetic material, the best bows are made from Brazilian pernambuco wood, a dense reddish-orange timber used specifically in making instrument bows. But the bow hair is the most important aspect of this part of the instrument; without it, the musician would have nothing to drag across the strings.
Violin bow hair is usually made from Mongolian horsetail hair, but Argentine bow hair is also common. The bow hair is attached to the wood at the far end of the bow, and to the frog – the adjustable piece of ebony allowing the musician to fine-tune the bow’s tension – at the near end.
For a violin bow, an instrument maker will often use between 150 and 200 strands of bow hair. The process of affixing the bow hair to the handle and the frog is called – perhaps unsurprisingly – hairing. This is actually an issue of routine maintenance as well as initial construction, since bow hair eventually wears out and must be replaced periodically. A truly dedicated violin player will know how to hair his or her own bow.
Horsehair for the bow is purchased in uniform lengths to allow relatively simple installation. From this bundle of bow hair, the artisan draws the proper number of strands, and uses a very strong thread to knot the bow hair together at one end. He affixes one end of the bundle into the mortise, a gap at one end of the bow suited to this purpose.
Then, with the frog pushed all the way forward, the artisan measures the bow hair to length, cuts off the excess, and arranges and combs it until it’s perfectly straight. Finally, he attaches the remaining end to the frog. After applying some rosin to the hair, he’s finished the process.
While every component of the violin is vital to a good performance, bow hair is perhaps the most demanding of quality and maintenance. Cheap, low-quality bow hair will result in a poor sound, and without regular maintenance even the highest grade of horsetail hair will eventually falter. Stradivari knew this, and throughout history, many other instrument makers have followed his example.