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.

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