Hi Wim, Find out who the manufacturer is/was and if there is a stringing scale for the instrument (it may be written on the nut (agraffe position) or the bridge or hitch rail or pinblock. Do not substitute steel for brass. Phosphor bronze is use form making wippen springs in grands. It should have a high breaking % point but I am no expert of that matter. I followed the scales on the instruments. A Martin, and WIlson and the fp was by Regier. Newton
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