<P> The manufacture of bows is considered a demanding craft, and well - made bows command high prices . Part of the bow maker's skill is the ability to choose high quality material for the stick . Historically, Western bows have been made of pernambuco wood from Brazil . However, pernambuco is now an endangered species whose export is regulated by international treaty, so makers are currently adopting other materials: woods such as Ipê (Tabebuia) and synthetic materials, such as carbon fiber epoxy composite and fiberglass . Carbon fiber bows have become very popular, and some of the better carbon fiber bows are now comparable to fine pernambuco sticks . </P> <P> For the frog, which holds and adjusts the near end of the horsehair, ebony is most often used, but other materials, often decorative, were used as well, such as ivory and tortoiseshell . Materials such as mother of pearl or abalone shell are often used on the slide which covers the mortise, as well as in round decorative "eyes" inlaid on the side surfaces . Sometimes "Parisian eyes" are used, with the circle of shell surrounded by a metal ring . The metal parts of the frog, or mountings, may be used by the maker to mark various grades of bow, ordinary bows being mounted with nickel silver, better bows with silver, and the finest being gold - mounted . (Not all makers adhere uniformly to this practice .) Near the frog is the grip, which is made of a wire, silk, or "whalebone" wrap and a thumb cushion made of leather or snakeskin . The tip plate of the bow may be made of bone, ivory, mammoth ivory, or metal, such as silver . </P> <P> A bow maker or archetier typically uses between 150 and 200 hairs from the tail of a horse for a violin bow . Bows for other members of the violin family typically have a wider ribbon, using more hairs . There is a widely held belief among string players, neither proven nor disproven scientifically, that white hair produces a "smoother" sound and black hair (used mainly for double bass bows) is coarser and thus produces a "rougher" sound . Lower quality (inexpensive) bows often use nylon or synthetic hair . Rosin, or colophony, a hard, sticky substance made from resin (sometimes mixed with wax), is regularly applied to the bow hair to increase friction . </P> <P> In making a wooden bow, the greater part of the woodworking is done on a straight stick . According to James McKean, "the bow maker graduates the stick in precise gradations so that it is evenly flexible throughout". These gradations were originally calculated by François Tourte, discussed below . In order to shape the curve or "camber" of the bow stick, the maker carefully heats the stick in an alcohol flame, a few inches at a time, bending the heated stick gradually to the proper shape . A metal or wooden template is used to get the model's exact curve and shape while heating . </P>

How many horse hairs are on a violin bow