Strings for early keyboard instruments

Stringing is a very delicate part of the conservation of early keyboards as departing from a not too wide margin of string tension can lead to a poor sound or to a twisted instrument with possibly irreversible damage to the soundboard, bridge or nut, and also broken strings. Apparently, instrument makers did not calculated scientifically the gauges they used in their instruments, as we do now. They must have used trial and error to come with the right gauges, and passed that experience on to their apprentices; and this situation lasted probably until the first quarter of the ninteenth century.

As metallurgy and science in general developed, improvements in the wire making industry resulted in a much stronger iron wire. For example, the discovery of the addition of manganese to the alloy allowed the possibility to have a wire that will stand higher loads. While this was welcomed by engineers, it came with a cost to the musical instruments making. In order to have a pleasent sound, strings have to be tightly stretched, but the wooden instruments were not capable to hold such load without twisting or breaking. Then the race to have stronger cases in the instruments began, and only in the second half of the nineteenth century a balance between the needed tensile strength in the strings and the construction of the cases was reached, mostly by the introduction of the cast iron frame. This is basically the period when the modern piano started. Harpsichords, clavichords and spinets were left behind even before this race began, as people favored the fortepiano. The last harpsichords made in England date from the first decade of the nineteenth century.

String calculation charts.

Even today, conservators (sometimes referred to as restorers, techincians, etc.) struggle to find the right strings for an instrument. There are a few causes for this, being one that the original strings are not present anymore and have been replaced with more modern ones, sometimes at the point that modern piano wire was used, ruining the instrument. Another one is the lack of experience. There are different string calculators, but they will give you information about the diameter of a string necessary to obtain a certain pitch, given a density. But the calculator cannot predict if a specific instrument will twist (or re-twist) or not under such a load. Also, there were typical stringing guidelines in different periods. For example, square pianos by Beyer or Beck (around 1780s) had red brass cores in the wound bass strings. Another frequent problem is when new strings break. Was it due to a miss-calculation of the strings, the wrong alloy, errors in the measurements of the speaking lengths, a poor manufacture of the eyes, too much bending of the wire when fitting the wrest pin, or was a defective wire? Sometimes a newly restored instrument seems fine with the new strings and after a few weeks the bridge is tilting or detaching, the soundboard sinking, or the whole instrument is twisting. The result is that the strings have to be removed, the damage repaired, probably by taking out the soundboard and/or bridge, and restring it again. If the instrument is in another city or country, the cost of bringing the instrument back to the workshop has to be added. I guess all restorers had at one point one of such issues, and that's when they decided to work only with an informed calculation. Such calculations can be obtained from a few restorers who have a big enough database and experience in stringing, and usually they cost less than one hundred pounds (110 euros, or 120 american dollars). If you want to have a string calculation, please send us an email to the following address and we will contact you: cesarhernandez1967(at)


Also, we can attend enquiries in Spanish, Italian, French and Russian.

We can also provide covered strings for grand and square pianos, and also plain strings in either whole sets or individual strings. Also, strings for harpsichords and clavichords. We can replicate probably any metal string (for sitars, psalteries, etc.), if you can send it, or its specifications.


Covered strings for square pianos: £15.50 for open wound, £17.50 for close wound. Close wound for grand pianos: £19.00.

Individual plain strings: £6.00 for brass or red brass, £5.00 for iron. All prices include the 'eye' (the loop for hooking the string in the hitch-pin) to your specification. Please send the string if you can, or a photograph.

For other less common types of strings, please contact me. The postage is not included in the price. For whole sets of bass and plain strings, I can make a small discount. I have not seen any problem to send strings to the continent due to Brexit, but you may have to pay some taxes.

Payments can be made through PayPal (we will add 4% comissions) or bank transfer, but bank transfers from North America will require an extra comission of 5%.