When pianos are built, the builders concern themselves with lubrication of moving parts in a rather fundamental way. They are concerned with new material assembled under controlled atmospheric conditions and lubrication is a very minor consideration in construction process. Obvious friction points such as those in the trap work are greased or graphited. In that complicated mechanism called the action, many friction points are treated with a permanent lubrication such as burnished graphite or were designed to be self-lubricating through use of felt against metal or, more recently, teflon against metal.
When the pianos are completed and shipped, further thought is not given to lubrication since factory people generally have no other contact with the instruments. Once the pianos are sold, however, a whole new set of problems begins to develop, including wear and tear, atmospheric extremes, abuse, and neglect. Lubrication is also one of these problems.
The word “lubricate” comes from Latin lubricare, which means “to make slippery.” The trick with piano friction points is to make them slippery and keep them slippery for extended periods of time. A lack of lubrication creates two general problems - sluggish response of moving parts and noise in the form of squeaks.
The anatomy of the piano creates other problems. There are no reservoirs to store lubrication such as oil pans or grease cups. Instead, the lubricants often must function between dissimilar materials, usually as thin films while exposed to accumulating dust and dirt. They must hold well through periods of use, must break down during disuse, and must not react with the host materials by creating any chemical change.
With the above criteria in mind, let examine the materials used as piano part lubricants. They fall into two general categories: (1) Solids and powdered solids include soapstone, talc, graphite, and teflon. (2) Liquids include tallow, grease of various kinds, and liquids that utilize some of the powders in suspension. The list of liquids must be expanded to include the sprays available today that have proven to be useful and time saving.
Many years ago one of the standard lubricants for piano parts was mutton tallow into which was stirred a fair amount of talc or baby powder. With the demise of the neighbourhood butcher shop, mutton tallow has been difficult to acquire. However, if you know a butcher who can get you some mutton fat, you can make a life-time supply of mutton tallow lubricant very inexpensively. Simply put the raw fat in a frying pan and fry it at low heat until it turns to a liquid. Skim or strain the liquid so as to separate it from any fiber residue and allow it to cool. The tallow will be a white waxlike grease. An additional reheating and skimming will improve the quality by leaving behind any missed residue or poor-quality fat. Into this refined tallow stir as much Johnson’s baby powder as it will hold without losing its consistency as a grease.
A contemporary substitute for mutton tallow and talc is...
Read more at:
https://www.professionalpianotunerlondon.co.uk/post/lubrication-of-piano-parts
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