Wire

The subject of wire choice for early pianos ranks with that of leather for ‘World’s Most Controversial Topic’ among early piano restoration and copy builders. However, we will plunge into the heart of the subject and let the arrows fly as they will!

What is at stake here is that the metallurgy of early wire was variable and changeable, and neither the iron, nor red and yellow brass wires are produced in quite the same way as they were. While this may not seem important on first revelation, one has only to string up an octave or so on an early piano with the appropriate gauge of a modern high strength steel such as supplied by Roslau to hear that the sound is overly ‘bright’; filled with partials (harmonic overtones inherent in a struck string) that are too pronounced to be pleasant.

There is debate on why this occurs, but the general consensus seems to have formed around the crystalline structure of modern high strength steel producing less damping action on partials, allowing them to be more readily heard. The additional stiffness of the  modern string advances the inharmonicity induced by the captive ends of the string, whose thickness acts to raise the frequency of the partials slightly above the mathematical values they should normally have. Also, as we will discuss in a moment, a string always sounds best when near its plastic elongation point, and with modern high strength steel wire, if we use a string at the right diameter (gauge) it will be very far away indeed from its plastic deformation point, so false beats can be introduced.

Old iron is a detailed subject, and you are recommended to read an excellent tract on the subject by Stephen Birkett, but we can state in general that using the appropriate wire on a piano can and does go a long way towards recreating the correct sound of the instrument. Happily there are some suppliers out there to help with this, and perhaps more coming with time.

Stephen Birkett has now completed the bulk of his researches in early iron and is in the process of starting to draw wire for pianos, having successfully drawn wire for harpsichords, now strung up and in use on instruments built or returned to currency by Owen Daley and Anne Acker among others. The results were extremely pleasing when I heard them in Cincinnati at the North American Historical Keyboard Society meeting this March. Several of us now have orders in for Birkett’s “P-Wire”, which closely follows the original metallurgy of including phosphorus as the alloy to lock the crystal grains together and provide strength and resonance. The wire is very slow to rust, stretch is almost eliminated, and a medocre instrument becomes alive under this new wire. Quantity will be limited for the next few months but write Stephen at stephen@fortepianos.com

Results to date with P-Wire and Birketts ‘Berlin’ wire are very satisfactory. On the Andrew Reuss piano, the wire gave one early stretch then was stable and reamins so. The liveliness to the sound that often develops over perhaps a month with Rose wire was there from the start wit Birkett’s new wire. While none of us who have now compared them believe that the Birkett approach is overwhelmingly distinct from the Rose wire, I do like the extra stability, immediacy of ‘brightness’, and in subtle ways, the wire offers a new tone color to our pallet. As with all subjective comparisons, trial towards a personal preference is the only adequate approach.

Malcolm Rose is perhaps the best known supplier of wire to the builder and restorer, with a full range of iron and brass wire, along with overspun type wire, suitable for the early and mid 19th C pianos. I have used Rose wire for some 12 years now and largely with success in all applications. This is a lower carbon wire but the exact metallurgy is not discussed in detail, and may be something we can talk about later here.

There are 4 types of iron wire offered, A-D, with A suitable particularly for harpsichord use, B for our early squares and grands to perhaps 1820, and C & D for later squares and grands. I have had excellent success with Rose B, and mostly good success with Rose D, though I did get one spool that was extremely brittle, to the point that a successful hitch loop could not be formed. It was replaced at once without question, and the next spool was correct.

Some pianos have fairly aggressive scalings, meaning that the length of the wire for a given diameter and intended pitch is long, which takes the wire to nearer its breaking point. In general, a wire sounds brightest and clearest just before it experiences plastic deformation and breaks. Realistically, designing a scale up to that point would result in a lot of broken strings during performance and tuning would be a nightmare, so most scalings take the wire up to a few half steps of the breaking point. If we use a wire that is naturally lower in strength, a scaling that works for one wire type might well break another type, and variations in the wire manufacture will show as brittle stings. A Collard and Collard grand from 1844 compared to a Broadwood from the same year can reveal a fairly large difference is the scaling of the treble. Fortunately, our little squares generally follow a similar scaling which is not particularly aggressive, so broken strings on a late 18th to first quarter 19th C piano are not usually a problem.

Malcolm Rose and David Law have produced a Handbook of Historical Stringing Practice that should be in your library if you are thinking of embarking on the practice of restoration. Additionally, early Broadwood pianos have their keys inked or stamped with the gauge number of the string for that note, which can be converted into a wire diameter easily.

Broadwood gauge markings

1793 Broadwood square showing gauge in treble

It is critical to replace a string with the proper diameter! It will not sound right otherwise, and can badly damage the instrument if too heavy a gauge. I would insert that being off by a single gauge number either way is unlikely to be catastrophic, but a full set of strings several gauges too thick will quickly wreck a wrestplank or case connection to the baseboards, or worse!

Alternates to Rose wire include Stephen Paulello wire which comes in various strengths similar to Rose, but is reportedly less prone to stretch with time and so comes to a tune more rapidly, and with very good results. Arno pianos carries this wire in the States. http://www.arnopianos.com/paulello.pdf

 Also spoken of is a stainless steel wire from Puresound which has been used and favorable reports received. It is certainly not anything like the historical wire we encounter in old instruments, but with a lower strength it appears to perform well, and it won’t rust, so the strings stay nice and bright. I have not yet used it but would welcome reports specifically from square piano restorers on its merits.

Marc Vogel supplies Westphalion iron and a brass wire, which as I understand is popular among the harpsichord builders and some piano restorers.

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Stringing an early piano from scratch can be slightly daunting to the beginner, as there are usually no holes in the tuning pins, and certainly there were none originally. Having selected our wire type, and with the proper scaling at hand to see where the diameters will change over, we can begin with setting up the wire to remove from the spool. Rose wire comes on convenient plastic spools which I prefer to simple coils, but perhaps not as convenient as the dispensers that bulk modern wire can be provided on. The wire was straight, and is now coiled and wants to return somewhat to being straight, so once we release it from the anchor on the spool it will begin to rapidly unwind and tangle within the spool, a disaster for getting it back off again without considerable fiddling and perhaps kinking, which is to be avoided at all cost.

A wire brake is the commonest approach, with any number of ways to make it work. Below is my version, which services well.

Wire brake spool

The wire is fed through the leather lined brake pads, which are screwed down to create a tension so that the wire is PULLED through under some tension, so that when we make the hitch loop no more is pulled out in the process. It helps to lay out a work surface as long as you will need to pull the wire to, for staging the measuring tape and cutting tools.

With the wire pulled out at least 6 feet from the brake, we can start the loop. Spooling off too little wire results in possibly putting a twist into the wire, which will reduce the tension it can carry and risk creating false harmonics. You need a tool to make the loop, such as the combination tuning hammers that harpsichord tuners use with an open loop at the top, or taking a cup hook and cutting away enough so that it is easy to put wire on and remove it. The diameter of the hook should be at least as big as the hitch pin diameter, and perhaps a bit more.

Tuning wrench and loop hook

Early square pianos feature separate strings, two for each note over the whole compass. The technique for stringing is to make a loop at the end of the string which will go over the hitch pin, then cut to length and wind onto the tuning pin. Both ends need to hold without slipping. For the hitch loop, I began as I was taught for harpsichords by David Way; make the loop, followed by a few spiral twists, then a series of close turns and wiggle off or cut the last inch or two of the loop. You can see this demonstrated by Carey Beebe in this YouTube video (LOOPS).

The trouble is that while this works nicely for tinned harpsichord wire, it is really not so good for piano wire. Unless you make a LOT of close turns, wrapping REALLY tightly, the loop starts to slip. The loop collapses, making it hard to ever get off, and may begin to unravel. A dot of super glue stops this cold, and I have seen very old, possibly original wire, with what appears to be rosin dots on the loop, so this has been a problem for awhile.

The deal is, you can make the loop featuring what seems to have been the ‘shop standard’ style loop simply and effectively, and never have a loop slip again. Below are pictures of several original loops from three different pianos, as kindly supplied by David Hunt:

Broadwood string loops

Broadwood loops ~1812

Longman and Broderip

Stodart string Loops

Stodart, 1785

The technique is simplicity itself; make the loop, followed by 8 to 12 spirals, then double back on the spirals about 1.5 turns, pulling a bit hard, and crank off the last bit. Loop won’t slip! And, “you’re doing it like the early professionals”.

Putting the wire onto the pin can be done in several ways. To begin with, if this hurts your hands or fingers, or you stick yourself more than once or twice at most, you are trying too hard. This is not a job where we wrestle grim death to the ground! The old guys stood and strung these things all day long, and went home happy. So can you, with a little practice.

Carey Beebe again demonstrates putting the wire on a harpsichord pin (HERE). This technique works well for the lighter weight harpsichord wire, but as the wire gauge passes about 0.55mm it will tend to wind back off the pin quickly, leaving little of the spiral in place. However, if you will catch it at the bottom and continue as shown, the basic technique works the same. You want to have the top of the pin where the flats (to fit the tuning wrench) catch the wire, also catch part of the spiral. Wind down 5 or 6 turns, crank off the remaining bit of wire, and continue to wind neat coils until the pin is positioned over the hole, then keeping tension, push in the pin, twist slightly to again keep tension, and drive the pin in. Keeping everything under tension is the key to success here, but a very little tension is all you need.

An alternative approach is to wind the coil of wire on a mandrel smaller than the pin, leaving a coil and spiral tail that is loose enough to just allow the pin to be inserted into it, but tight enough such that with finger pressure it will grab the tuning pin on tightening. This can work, as demonstrated below by David Hackett, with the advantage that if a pin must loosened, the whole winding is not lost at once.

Winding square Piano pin

Making the spiral catch

square piano pin winding

Starting the coil on the mandrel

winding pin square piano

Inserting the tuning pin

square piano pin winding coil

Coiling onto the pin

inserting tuning pin square piano

Ready to insert into wrestplank

 

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