Belly edge thickness - corners 4.5 4.7 5.8 C bouts 4.3 4.5 5. As viola neck and fingerboard lengths are variable, the width at the bottom end also varies. The actual width at the bottom is a projection from this point. These thicknesses are for new fingerboards, old ones well below them, as well, new ones may be made well over size to compensate for thin necks whose replacement is not justified. Thickness across bottom of fingerboard is same as edges for violins and violas.
Cello fingerboards have a bevel on the C side.
Width of the C bevel at the nut is about 9mm, and 22mm at the bottom. The angle of the C bevel is about 55 degrees. The underside of the fingerboard at the bottom should have a constant radius of about 45 mm. Under edges are feathered to zero beginning approx. For instruments with a high abrupt arch allow more height so that the bottom of the fingerboard clears the table by at least 2.5 mm at the closest point.