Les 5 types d'aciers

5 types of wires

  • To harmonize the stress throughout the stringing in modern instruments
  • Because using a steel with optimal stress load makes the sound richer, equalizes the tones, reduces the stringing’s stabilization time, facilitates tuning and improves its holding.
  • To restring XIXth century pianos with wires comparable to those used originally


  • To those who have to solve a problem of strings breaking in the trebles or of over-stressed  wound strings in the bass.
  • Breaking load superior to Type M, i.e. superior to current standard wires.
  • Polished or nickel-plated finish - 500g or 2 kg rolls

TYPE M (or Modern)

  • Fine, bright treble and excellent spectral balance
  • Mechanical characteristics corresponding to current standard wires
  • Polished or nickel-plated finish - 500g or 2 kg rolls

Type 0 (Zero)

  • For post-romantic instruments or in hybrid stringing on modern instruments over-stressed in the medium range : use type 0 in medium, associated with Type M, possibly Type XM, in the trebles.
  • Rich and complex tone
  • Similar to French wires produced in Firminy around 1880
  • Breaking load inferior to Type M
  • Polished or nickel-plated finish - 500g or 2 kg rolls


  • For romantic instruments or in hybrid stringing on modern instruments under-stressed at the break: use Type 1 associated with Type 0 and Type M
  • The warm, deep sound of a ‘cello
  • Breaking load inferior to Type 0
  • Polished or nickel-plated finish - 500g rolls

Type 2

  • Romantic Movement instruments
  • The year of construction is not a pertinent criterion for the choice of wire types
  • Breaking load inferior to Type 1
  • Inappropriate for instruments posterior to 1880
  • Polished finish only - 500g or 250g rolls.

What are the differences ?

The 5 types of STEPHEN PAULELLO wires result from two different aspects of their manufacturing:

  • choosing raw material according to its composition
  • perfecting methods of wire drawing which modify several mechanical or chemical parameters: speed  through the dies, rate of metal deformation, temperature, lubricant …

This results in 5 degrees of mechanical  performance, from highly traction resistant steel (Type XM), to almost pure, less resistant iron, resembling early XIXth century stringings (Type 2).

Breaking loads extend from 3000 N/mm2 (type XM’s small diameters) to 1000 N/mm2 (type 2’s large diameters) modern stringings

Tables of characteristics of the 5 Types of wires

3 ways to choose the most suitable types of wire

  • Consult the stringing instructions corresponding to the make and model of the piano
  • Use the TYPOGRAM, a calculation sheet which can be downloaded;  enter the dimensions of the piano strings and choose the type of steel to use for each note.
  • Ask for a personalized optimization of the scaling : in addition to prescribing the best type of wire for each note, this service includes recalculation of the wires’ diameters (€300).

You will notice that most instruments, ancient or modern, require hybrid scaling, combining several types of wire


Packaged in 2Kg rolls of 23 cm in diameter, the wires have less residual tension, thereby limiting the risk of impure strings.