Key Covers

Updated June 8 2011

 

English square pianos almost invariably feature ivory naturals and ebony sharps, (with a few exceptions from the first years of production where the keyboard is reversed), with sycamore (maple) wood fronts cut as an ogee molding. Occasionally American squares will be seen with mother of pearl naturals, but I am unaware of any English piano with this cover material. Broadwood pianos in particular sported a premium ivory cover, between 2.4 and 3 mm thick, and of choice select ivory. Beyer, Ganer, and others also chose the finest ivory for early instruments, and Tomkisons are found to be excellent as well. Longman and Broderip on the other hand used ivory that probably looked great new, but was thinner and of less quality, the consequence of which is that these ‘trade’ pianos can be found with ivory in poor condition or missing, where the thin material curled with moisture and popped off the key lever, or cracked and split, discolored, etc.

Early key covers are always two pieces, and head that is the width of the key lever front, and a tail piece, also the width of the key lever tail.

Once missing, it is a shame not to replace the covers with something that looks and feels correct, but our challenge is not small. For obvious and valid reasons, new ivory is difficult to come by. International Piano Supply can provide new ivory sets cut from museum ivory for a price, but that is only in the USA and difficulties remain to be solved regarding the width and length. Recovered ivory from scrapped pianos can service, but we have some particular requirements that make this problematic. Bone and plastics will be considered in this space, so please return for additional material that will be added. 

The first problem, and easiest to solve, is length. Modern pianos have natural heads that are 49 or 50 mm long, early pianos from ~39 to 43 mm and nominally about 42mm. Width may vary slightly as well, though generally modern covers will match the early heads nicely, or need only a small trim. The tails are another matter however. If you need to do a complete replacement, your early square piano almost certainly has what are known as ‘wide D’ tails. In laying out a key board the C, D, and E keys are bordered by two sharps, the F, G, A, and B by three sharps. A well known expert on early pianos presents the problem in a well reasoned manner below:

“We have to make some ‘rules’ before designing a keyboard.  The usually accepted ones are:

1) all the naturals are the same width (at the front).  Let’s call this a Unit.

2) all the sharps are the same width

3) the design will be symmetrical; e.g. G# sits centrally between G and A, and F is a mirror image of B.

 I have never seen a keyboard where these rules do not hold*.  But note that C is not necessarily the same as F.

 From now on, there are choices, because at the tails, we have five keys to go into three units (C-E) and then seven into four units (F-B).  3/5 is 0.6, but 4/7 is 0.57, therefore there is more space for the five keys C-E.  You could make all the tails just this, i.e. C-E 0.6 units, and F-B 0.57 units, but rule 2 says that all the sharps have to be the same.  Making the F#, G#, A# the same as the other two makes the gaps uncomfortably narrow, so we usually choose the 0.57 as the sharp width, and then distribute the extra amongst the tails of CDE. 

The Broadwood method does make the C the same as the F, and hence the tail of the D very wide, whereas the ‘Continental’ way makes the tails of CDE about equal.  There are other possibilities, such as choosing this for CDE, keeping the sharp width at 0.57, but displacing the F# downwards and the A# upwards, to make the gaps easier for the fingers.  This tends to be a ‘modern’ trick, as in the old days we didn’t play on the tails of the white notes.  So even following the rules, there are infinite possibilities!  Then allow for the fact that the keys were cut by hand, and there is a certain amount of error – e.g. not all the C’s are exactly the same.  But it’s fun trying to work out what the intention was!”

 *Editors note – Frederick Beck chose to alter the width of the sharps, leaving all the natural tails the same width!

What this means to the restorer is that you must find wide D tails, and that is tough. The low A of a modern piano has a wide tail, so 5 of those trimmed to width will work. The treble f3 or c3 is full width, similar to the top c of a modern piano, so one of those. A 5 octave square has 36 naturals, 25 sharps, a 5.5 has 40 naturals and 28 sharps. Modern pianos have 52 naturals and 36 sharps, so plan ahead when doing a full replacement.

Recovered ivory is available from various sources on the web and occasionally through E Bay, though quality varies between acceptable and useless junk. Beware! Ask questions and get answers before ordering any quantity. Your local piano store may be of assistance in providing or locating a source for you. Avoid ivory that is curled and/or discolored, and please refrain from wholesale replacement unless it is really needed. There is a  Broadwood grand in South Carolina that has had all the covers replaced with more modern ivory many years ago, with the result that the original material might have still presented well, whereas the replacement material looks like a wreck!

Moving away from ivory, our next choice might be bone. It feels right, and looks good, though somewhat more uniformly white and without visual texture when compared with ivory. It soils more easily, is much more porous, and does not have the right grain  appearance. It is not inexpensive, and a whole recovering of a 5 octave instrument will cost between $250 and $350 for high grade bone cut to size. It does not provide a good match to existing ivory when used side by side. Bone is available from European sources, and from Lutz Bungart at the Instrument Workshop in the States (see links). Both Ivory and bone can be had at John Nelson Woodworking Catalog which also features recovering entire keyboard services. Guitar Parts and More sells head and tails, separately or in sets, in bone and ivory.

It is a shame that ivory is such an excellent choice for this application, for the harvesting of ivory is an activity of which we as a species should be deeply ashamed. In almost all cases the entire elephant is sacrificed for one or two tusks, and the removal process is the stuff of horror stories. The replacement of ivory on our little square pianos is not sufficient to cause more than a fleeting flicker of interest to this trade, but fundamentally, demand is demand, ladies and gentlemen. Though the legitimate market has ceased, a black market remains, and several metric tons of ivory leave Africa yearly. Recycling old ivory or ‘museum’ ivory seems harmless, as the elephant paid the price long ago. I am mindful of unintended consequences though, and at prices of between $9 and $40 a head/tail set for new ivory, a subtle market can still cause the demise of elephants. Therefore, we will consider synthetic alternatives with an eye towards adoption.

Ivorine (pyralin)is a plastic that has been around for years, and is used for the better modern pianos. It looks and feels well enough, but is unconvincing on early pianos. However, a full set can be acceptable if you want to get something on without too much work, and it is available in sheets so the wide D tail is accommodated. Vagias is another plastic commonly in use, though it comes in modern sizes pre-cut. Schaff Piano Supply in the US carries these products, but requires you to contact them directly and plead your case as they are wholesale only.

Elforyn is yet another synthetic developed for the pool cue market. It comes with and without simulated grain, but the keytops are currently available only in ungrained.

David Hackett and I have recently explored two synthetics from the UK, and he has posted these on his web site for review. As this site is dedicated to retaining information as it passes through, I have taken the liberty to re-post this information below:

Substitute ivory key tops keytops casein

“All English square pianos had ivory natural keys.  These do wear, though (some can be worn right though to the wood) and the front parts especially are frequently chipped, damaged, or missing.   Most restorers working in England find replacements from ‘recycled’ pianos, but even then, there can be problems with thickness or quality: later Victorian  uprights (the usual source of recycled ivory) had rather thin ivory.  And those wide D tails (not to mention the top F or C tails) can be a problem.  There’s also the point that export of ivory to other countries can be interesting (even though CITES criteria may be met).
 
  However, our Friend Tom Strange recently requested samples of two possible alternative materials, and these were sent to Square Pianos HQ.  They are from GPS Agencies in Chichester (my old Home City) and are  ’Casein Grained Ivory’ (the B key) and  ’Polyester Grained Ivory’ (the C key).  [I made up sample keys for fun and experience.]  Both are nominally 3mm (piano keys are seldom more than 2mm, but spinet and harpsichord keys are frequently thicker).  But whereas the polyester was flat and uniform, the casein sample was variable in thickness, and far from flat.  
  From the point of view of working, edges could be planed in both cases, or sanded of course. When band sawing to width, both were a bit ‘chippy’ on the underside of the cut, but not excessively so.  The big difference was that the polyester, being flat and uniform, could easily be shaped in one piece, but the casein was more easily handle for two-piece tops – just like real ivory! So better to cut rough heads and tails, and then thickness to 2.5mm or whatever on the band saw.  
  As received, the polyester had a particularly ‘plasticky’ surface, but it could easily be sanded and polished (0000 steel wool suggested to finish) to something more sympathetic.  For colour, the polyester was perhaps slightly ‘pink’, but the casein was a more green/yellow shade of white, and nearer to most of my ivory.  The casein also finished beautifully (even better) with steel wool, and the ‘feel’ was excellent.  The grain appearance also more convincing.
  You’ve probably gathered by now that my strong preference was for the casein, even though it’s more work.  My Big Harpsichord has recycled ivory from a nineteenth-century American organ, but otherwise I would be very tempted to go for the casein from GPS!”

www.ivoryalternative.com

ivory alternative piano

Alternatives on white paper

Ivory substitutes Broadwood keyboard

Ivory substitutes compared against Broadwood keyboard

 Since March we have continued our quest for the best substitutes out there, and our conclusions are about the same, though David and I feel the cream Elforyn is a better side by side substitute for ivory than Casein, but casein does have a texture that is attractive, if a bit overdone. Below are the best examples of these alternatives finished into keys, and shown at maximum contrast. In real applications the graining is somewhat more subtle.

Ivory substitute

4 ivory substitutes on a flatbed scanner for maximum contrast

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