Friday, March 18, 2011

FINAL STEPS

The frog illustrated in some previous posts has been mounted on a stick and the bow is nearly finished. This bow is for Antonio Anselmi, a violinist in Rome who is concertmaster of the I Musici chamber orchestra. The selection of the stick was critical for this bow as it always is for the bow maker. Anselmi plays on a late Amati with a Tourte weighing about 57 grams and he wants a soprano vocal quality to the sound. So the challenge was to find a stick with the right tonal potential of low to medium density wood. One such stick was found but ended up being set aside well into the process because intuitively it lacked too many other requisite characters. So a stick of very responsive wood of medium density was chosen and the projected weight raised slightly to 59 grams. The stick is quite powerful but much of this is placed in reserve through the cambering approach to give the stick flexibility. Several earlier bows I made with the same wood proved to have a pure, singing upper register.

In the picture you can see the unlined frog while the screw and evelet are lubricated. An unlined frog should not swing laterally on the stick as this can weaken the edges. So the frog is carefully adjusted for a snug fit. Finally the bow is measured and the camber recorded so I have the record of the bow and can duplicate aspects of it in future bows if need be. The diameter of the stick is measured in 12 places and also the height of the frog and head are noted.

Now the bow is photographed and the basic work is done. But the bow is not complete; it is now rosined and played for a day or two. If there are any final adjustments to be made to the camber they will be made before the bow is shipped.

Wednesday, March 9, 2011

REHAIRING

Rehairing may be the most common work done on bows but it is not the easiest. Since the most delicate parts of a bow are open during rehair, both skill and care are necessary to avoid damage. It also requires a lot of experience to select the correct amount of hair and ensure that it is of even tension. There is also a wide range in hair quality and the conscientious rehairer will use only the best, which can easily cost three times as much as ordinary hair. The good rehair person is also checking over a bow to make sure no problems arise like a frog that becomes too loose or an eyelet that needs replacing. More serious problems like an enlarged screw hole can be brought to the attention of the player. That way the problem can be repaired before the bow becomes weakened.

In addition there are two basic methods of rehairing, one in which the hair is secured first in the head and the other where the hair is started in the frog. In France the hair is always started in the frog, which ensures that most of the work takes place with the frog mounted securely on the stick. When the hair is started in the head, the frog is loose and must be placed on an often ill-fitting jig to press in the wooden wedge that secures the hair. So while a competent person would no doubt do a good rehair with either method, I think the latter method is preferable, especially for a bow without a silver under-slide on the frog.

It’s rare for a bow to be damaged in general use and more damage occurs during rehair by poorly trained people. Although the frog is quite durable as long as it is securely mounted on the stick, it must of course be removed for rehairing. Then the under-slide or channel between the frog and stick is exposed as well as the knife-edged dovetail where the pearl slide fits. These edges are sharp and delicate, especially when there is no silver underslide. They are easily chipped of damaged. This makes the selection of a really competent and conscientious bow rehairer of importance. Too often in even well known shops the bow-person is under a lot of pressure and must work at top speed. It’s a very good idea to know the person rehairing your bow and their credentials. Every player is the guardian of their bow for it can be of use for generations of musicians.

Thursday, March 3, 2011

THE UNDERSLIDE.

The last step on the frog before polishing is to cut the underslide channel or coulisse where the frog slides on the stick. This is done freehand with a narrow chisel. Normally when it is completed we stamp a piece of thin silver in a press and glue it into the channel. This strengthens the area.

In this case we are leaving the coulisse unlined as Tourte and his contemporaries did in the late 18th and early 19th centuries. This is for several reasons. For one thing we want to minimize the weight of this bow and the silver lining weighs nearly one gram. In addition we want the tonal effect created by a frog of the lowest possible mass. And lastly the unlined frog enhanced the style of this bow, which is rooted in the early 19th century. Contrary to some opinions, this frog is quite durable with one exception. When the bow is being rehaired the fine edges of the coulisse are exposed and easily chipped. This bow should only be rehaired by a craftsperson with the required experience.

The stick, which has already been cambered and planed down to oversized dimensions, is then planed to match the frog’s underslide in such a way that the frog is in exactly the same axis as the head. Then the mortise is cut and the stick drilled. Finally a hole is drilled for the eyelet. At this point I have outlined the whole process of making a bow starting about two months ago. So rather than repeat myself I’ll cover the following steps in more general terms and write more on other areas of importance to bowmaking. Anyone who would like to know more can go back to the earlier posts.