Cellos have a concave shape and fitting a bridge accurately requires careful attention to detail. The feet of the bridge are sanded to match the curvature of the cello. The bridge plays an essential role in the sound quality of the cello because it is the mediating factor between the vibrations of the strings and the body of the cello. If the feet of the bridge are not shaped properly, the bridge won't be able to make firm contact with the cello and this will result in a diminished sound quality.
Place a large sheet of aluminium foil on the surface of the cello between the f-holes at the spot where the bridge will be located. The foil protects the surface of the cello as the bridge is sanded to fit the contour of the cello.
Tape a piece of medium-grit sandpaper to the foil with the grit side facing up and the smooth side on the foil.
Place the feet of the bridge on the sandpaper. Apply pressure while moving the feet back and forth on the sandpaper. Both feet should remain on the sandpaper at all times. The sandpaper and foil take the shape of the contour of the cello. Sanding the bridge on the cello helps to shape the feet to the contour of the cello.
Inspect the feet several times during the sanding process. The goal is to sand about 90 per cent of the bottom of each foot into a concave shape that fits the cello.
Remove the bridge from the sandpaper. Remove the foil from the cello and wipe off the dust from the cello with a lint-free cloth.
Place the bridge on the cello to check the fit. Lightly file the feet with a file until the bridge sits securely on the cello.
Insert the ball end of the C string into the tailpiece to lock it in place. Pull the opposite end of the string towards the headstock,making sure to place it in its groove in the bridge and the groove in the nut.
Pull the C tuning peg slightly away from the peg box. The tuning peg for the C string is the lower left side of the headstock. The G tuning peg is the upper left, D is the upper right, and A is the lower right. Thread the string through the hole in the tuning peg until it comes out the other side. Leave a short amount of slack in the string.
Turn the tuning peg counterclockwise to tighten the string. Gently push the tuning peg towards the peg box as the string is tightened. This allows the strings to wrap around the tuning peg as the string is tightened.
Repeat the process with the G, D and A strings. The D and A tuning pegs are turned clockwise to tighten the strings.
Slide the bridge onto the cello underneath the strings and stand the bridge upright and place each of the strings in the slot on the bridge.
Tune the strings to pitch once the bridge is in place.
The bridge lines up with the notches in the centre of the f-holes. The bridge should be halfway between the tailpiece of the cello and the fingerboard. The foil may be held in place by hand during the sanding process or secured with rubber bands or blue painter's tape. The bridge is held in place by the tension of the strings. This makes it necessary to install the strings first and the bridge second.