Because bass strings are made according to a piano’s specific scaling, ordering a new one is not as simple as picking up the phone and asking for a new string. The most accurate way to duplicate a bass string is to send the original string to the manufacturer. However, in the event of a time constraint, you can order an accurate duplication of a bass string by taking specific measurements for the manufacturer. Make sure to include the make, model, serial number, and string number with the order. (Pro tip: have the measurements ready before you call the manufacturer.)
You will need:
Tape measure in millimeters
A. Hitchpin loop to hitchpin wrap
B. Hitchpin loop to copper winding
C. Hitchpin loop to opposite end of copper winding
D. Length of copper winding
E. Steel core diameter
F. Copper underwrap diameter
G. Copper overwrap (if present) diameter
A: Loop to Wrap
Measure from the tip of the hitchpin loop to the end of the hitchpin winding.
B: Loop to Winding
Measure from the tip of the hitch pin loop to the beginning of the copper winding, either with calipers or with a tape measure. (Protip: if there are kinks in the steel wire from the bridge pins, use wire bending pliers to straighten the wire before measuring.)
C: Loop to Opposite Winding
Measure from the tip of the hitch pin to the opposite end (closest to the tuning pin) of the copper winding.
D: Length of Copper Winding
Measure the whole length of the copper winding with a tape measure.