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Failure of Kemble Bass Bridge & Repair

The Kemble Piano Company was established in 1911 by Michael Kemble in Stoke Newington, North London, and became one of Britain's most well-regarded manufacturers. The company is best known for its innovative, modern instruments which boast a warm, rich tone with a superb dynamic range.

Robert Kemble took the business over in the 1950s and, with sales growing rapidly, moved the company to a new factory in Bletchley, near today's city of Milton Keynes. The new factory boasted state of the art, modern equipment which allowed Kemble to satisfy the ever-growing demand for their pianos with a steady supply of new instruments.

Kemble became a household name and subsequently a desired stock item for dealers across the UK, and indeed the world.

The Kemble Company was so efficient at manufacturing pianos that they also made instruments for other iconic brands, in addition to their own range. These brands included Broadwood & Sons, Chappell, B.Squire, John Brinsmead, Cramer, Dietmann and more.

 

Common fault on the bass bridge in Kemble pianos


Kemble pianos of certain vintages have a common fault on the bass bridge which is always addressed during our reconditioning process of affected instruments. After the proper repair, the pianos can leave our workshop to perform faultlessly for many years to come.

 
Kemble Bass Bridge

The following photographs illustrate the failure and subsequent repair of a defective bass bridge in a Kemble piano.

The bridges are a very important component of a piano's construction as they are intrinsically linked to the piano's tonal quality, volume, and sustain. The bridges transmit vibrations from the strings into the soundboard and must be in good condition for optimal efficiency and to resist the tension of the strings.


Modern pianos typically have two bridges, namely the long bridge and the bass bridge. The long bridge spans the tenor and the treble sections and runs diagonally across the soundboard and the bass bridge sits in the bass section. Long bridges are usually comprised of two pieces of wood, the cap, and the root. The root of most bridges is usually constructed from vertically or horizontally laminated hardwood and the caps are generally made from solid hardwood such as maple or beech. Bass bridge construction varies tremendously between manufacturers as different methods of construction yield different results, which is a contributing factor in the range of different characteristics between makers.


This defect in certain Kemble pianos is caused by a faulty batch of glue which was used on the bass bridges for a limited period of time. Kemble was never aware that the glue they were using during this time period would ever present such issues. Unfortunately, these mistakes do happen from time to time in large scale manufacturing operations.

 

The first step of carrying out this repair is to [carefully] release the tension on the bass strings and remove them from the hitch pins.

By releasing the tension from the strings and moving them out of the way, our technicians can now remove the defective bridge, shelf and bridge root.

 

The glued joints between all the components that make up this bass bridge had failed.

In this particular Kemble piano, the bridge shelf was constructed from four pieces of plain-sawn beech wood. The quality of the wood is exactly what we would expect from a Kemble of this vintage and only the glue which holds it together had failed. We would like to point out that there was no defects in the wood itself.

 

On one of our trusty workbenches, which has seen the components of hundreds of different pianos over the years, our technician prepared the pieces of beech for re-gluing whilst maintaining the proper thickness of the individual pieces, so the original height of the bridge was preserved.


After the glue had cured and the four pieces were securely fastened together once more, the bridge was re-glued to the reconditioned shelf, and the shelf was glued to the reconditioned root.

 

After the glue between the shelf and the root had cured, the root was then glued to the soundboard in the original position. In the Sykes & Sons' workshop, we use a specially formulated glue, far stronger than the original, allowing us to guarantee our work for many years. The glue that we use for these repairs is a non-organic compound which has been especially developed to ensure the strongest possible joint.


We are very confident in the quality, strength and longevity of our specialist glue, as tests have shown it to be among the strongest wood adhesives available.

 

After all the glue had cured, we temporally reattached the original strings and brought them up to pitch.


We did this to firstly test the repaired bridge and then to take a sketch of the original string position over the bridge in order to make new, bespoke strings for the piano.


Generally speaking, modern pianos have approximately 230 strings, all of which need to be able to maintain the correct tension and produce a pleasant and 'healthy' sound.


The strings generate vibrations when they are struck by the hammers, which are then transmitted into the soundboard through the all-important bridges. In the tenor and treble sections of modern instruments, there are three strings per note. These strings are usually made from polished, round music wire. The bass strings consist of a steel core which is wrapped in soft copper.


Every string must perform exactly as expected and if they don't, like these ones didn't, then they are replaced.

 

We use high-quality industry-leading music wire and bespoke bass strings which are carefully crafted by master string makers in the UK and Germany.


In the photograph (from a different piano) you can see one of our piano technicians carefully attaching new strings which have been made especially for the individual piano.


New strings initially lose tension when they are first installed, as the metal stretches and they require several adjustments before they begin to retain the correct pitch. In some workshops, newly fitted strings are pulled above their elastic limit to stabilise them quicker, which saves time (and therefore money) but this can permanently damage the strings and reduce their life expectancy.

At Sykes & Sons, we attend to new strings over many careful sittings, which takes longer but is better for the strings over the long term.

 

Here is the finished article. An invisible bridge repair in a piano, with brand new bass strings, that can go on to serve the new owner without fault as soon as we finish reconditioning the rest of the instrument.

We could not possibly detail every single aspect in the craft of piano restoration on the website, nor can we provide a blanket list of all work that is carried out on every piano that passes through our workshop, because every instrument is different, but you will find an overview of some (not all) of the most crucial elements of preparing our stock on our workshop page.


We are more than happy to provide an itemised list of works done on any specific piano within our inventory upon request.

 

Every piano offered by Sykes & Sons has been carefully prepared in our fully equipped, climate-controlled workshop, where our own specialist technicians work with every instrument individually to maintain the high level of quality and finish that we are known for. Our aim is simple. High-quality pianos, an exemplary level of service, and ultimate customer satisfaction. Whether we are preparing a piano for professional or domestic use, our intention is always the same; for every piano to leave our workshop looking, sounding, and feeling just as it should. We can only guarantee that our pianos will provide many years of faultless service by meticulously finishing every instrument in-house, using only the finest parts and materials available in the trade.

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