A cello bow is now in process and as with the violin bow we make the fog first. This is because the frog needs to ready to mount on the stick very early on in the process. Since I covered the frog making process in earlier posts I’ll only cover what is unique to a cello frog.
The cello frog has a rounded heel or ‘talon’ so this necessitates a different approach in that area.
The amount of curve or radius of the heel varies quite a bit between bow makers and in general the earlier 19
th century bows have a bigger radius or are more rounded. There is an aesthetic and stylistic relationship between the curves of throat and the curve of the heel.
Since the length of the flat area on the bottom of the frog determines the length of the pearl slide, the rounder heels have a shorter slide all things being equal.
In this case our radius is relatively large. The tighter heel curve of late 19
th century makers like Lamy was a bit easier to make and made possible a longer pearl slide since the flat area on the frog was longer.
Once the frogs heel is rounded we fit the eyes in the frog sides and in this case we are using a eye ringed with silver or ‘grain et cercle”. . To receive the ring, a narrow groove is cut with a special drill bit, which cuts the recess for the pearl eye at the same time. Each bow maker makes these bits themselves to the requirements of their taste and style. Francois Tourte was probably the first to make this type of eye and to begin with the ring was fairly heavy, getting finer during the course of the 19th century. To make this eye a thin strip of silver is cut, bent into a ring and soldered. It is then put on a tapered rod or mandrel and hammered to the correct diameter. It is then filed until it fits snugly into its groove. The pearl eye is filed to fit and glued into its recess followed by the ring, which is hammered lightly into place. When the glue is set, any silver sitting proud can be filed off flush with the sides and the eye is completed.
