Some early piano makers attached instructions for maintaining their instruments inside the piano. John Broadwood fixed a small label on the inside of the spine of the instrument giving instructions in both English and French. William Rolfe and Muzio Clementi attached instructions inside the left hand compartment. Longman & Broderip fixed a page of instructions, one in English and another one in French both about A4 size on the underside of the internal cover. Although many Longman & Broderip square pianos have survived from the late 18th century, the majority of them are now missing their internal cover, a green silk covered board that rests in the instrument covering the internal parts. Therefore it is infrequent that these instructions are found. The picture below shows an example given in Longman & Broderip square piano of about 1791.
“Directions for the management of Longman & Broderip’s patent Piano Fortes sold at 26 Cheapside and 13 Haymarket London.
If the hammers, by use, get unequal, take out the fore board and turn the brass screw in the sticker, fixed in the key, with small pliers. It will cause the hammer to strike softer; the contrary will of course make the instrument louder.
Care must be taken that the screw is not turned in so far as to cause the hammer to remain up to the strings. If they rise up to an eight of an inch it will be sufficient. By paying a little attention to these directions you may regulate the tones to the greatest exactness.
To take a key out, press it down in front and lift up beyond the centre pin and it will come out with ease.
Longman & Broderip manufacture and sell, retail, wholesale and for exportation of all sorts of musical instruments with every article appertaining thereto on the most reasonable terms: also engrave, print, import and sell all the musical publications of this Country and every other part of Europe”
Note the use of the word “sticker” instead of “jack” in these instructions. The term “jack” would be used today.
Longman & Broderip were actually resellers and contracted piano makers to produce instruments on their behalf rather than make their own instruments. In particular they had contracts with John Geib and Thomas Culliford to make square pianos for them.