The Action and Pads

          This is the typical condition of concertina pads in older instruments. At first sight it just looks dirty,
          but when you examine the pads more closely, you'll notice the felt is partly deteriorated.
          A pad consists of a card board, felt and leather sandwich. The (leather) disk, on top of the pad, is
          connected to the leather bead, which is screwed on the (brass) arm.
          The bead/disk connection is flexible and adjusts the seating of the pad. 
          The oxidation on the riveted brass action (this is a Wheatstone) will interfere with movement of the
          lever.
 

          Left old,  right new pad. Notice the difference in size. The felt in the old pad has deteriorated.
          You can even see a hole in the side. Sometimes you can spot worn pads without having to open
          the instrument by checking the key height. Uneven key height can be a sign of deteriorated pads.

          This is a view of the same instrument, but with new pads and oxidation free action.
          A 48 key concertina has the same number of pads,  varying in size from  about 11 mm for the high
          notes to 24 mm or more for the lowest notes, depending on the type of instrument.
          The lower the note, the bigger the air hole needs to be to supply enough air. The amount of  travel
          of the key when it is pushed down, determines how high the pad will lift of the board. If the key travel
          is too little, the reeds (especially the lower ones) will not get enough air to vibrate fully. As a result the
          reed will be slow to speak and will have little or no harmonic spectrum.

          This view shows the action, springs and keys with the (black)  key base circle and  peg hole bushings.
          Springs used to be made out of brass.
          In this picture you can clearly see the oxidation on the springs. Old springs can create a lot of problems.
          Because brass looses its strength, brass springs can easily break, causing a note to constantly sound.
          In this instrument all the bushing and springs will have to be replaced, and the action and keys polished.

          This shows the finished action. Although we sometimes still use brass for our springs, we prefer steel.
          The advantage of steel springs is that you can adjust the key pressure much more accurate. They will
          also keep the pressure constant much longer.
          The height of the keys has a lot of influence on the sound quality of the instrument. When the reeds
          get the air they need, even brass reeds can sound loud and and fast.
          We set our action to 60-70 grams of key pressure and key travel somewhere between 3.2mm and 4.0 mm,
          depending make, age and type of concertina.

          Rebuilding an action on a standard 48 key English means in parts: 48 pads, 48 springs, 48 leather beads
          and disks, 48 key hole bushings, 48 peg hole bushings, 96 key base circles. All parts have to be hand made,
          to the original specifications.

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