The next adjustment is called the Let-Off adjustment. The purpose of this adjustment is to regulate the point at which the hammer head stops moving forward towards the piano strings. When correctly adjusted, the hammer will move to within 1/8" of the strings and then 'retrace' -or move in the opposite direction (back towards the hammer rail). Making this adjustment requires a 'light' and 'controlled' touch on the piano key. Begin by depressing the key very slowly while watching the hammer closely. Continue pressing the key down until the hammer retraces, and note the distance. (BTW, most hammers will have groves in the face of the hammer from years of striking the strings. When making this adjustment, it's important to consider this fact because the 1/8" space is measured from the string to the point where the hammer makes contact with the string, not the face of the hammer.) Turning the eyelet screw marked 'Piano -Let-Off' in a counter clockwise direction will increase the distance that the hammer travels before achieving let-off.

   Now we get to the player adjustments. First, the lost motion adjustment. Unlike the piano lost motion adjustment, you DO WANT a small amount of free play between the striker finger (marked 'B' in the diagram). When correctly adjusted, there should be no more that 1/16" and no less than 1/32" of free play between the capstan on the striker finger and the point where the capstan contacts the wippen. Here again, turning the capstan counter clockwise decreases the lost motion. To see a video of this adjustment being done, click here.

   Lastly, we come to the Stop-Rail adjustment; which might be the most difficult adjustment. Theoretically, it's purpose is to limit the throw of the striker pneumatic such that the pneumatic will not travel any further than the piano key travels. Note the words 'Key Dip' and 3/8" at the front of the piano key. This is how far the key should move to allow the piano action to go through its complete range of motion. Practically speaking, the stop rail adjustment should mimic the key dip. If the striker pneumatic is allowed to travel further than the key travels, this puts undue pressure on various parts of the piano action, which will eventually damage the parts. Fortunately, this adjustment rarely needs attention because it's set at the factory when the piano is assembled and tested, and the felt pad on the adjuster doesn't wear out because there's no friction at that point. It merely stops the striker finger from traveling any further. However, since the stop rail has to be removed when the stack is rebuilt, it's possible that it won't be put back in exactly the same place. The only way to make this adjustment is to compare the action of the keys to the action of the striker fingers. First, press the key all the way down to see where the parts in the action end up. Then pull the striker finger all the way up, and see where the parts in the action end up. The parts should end up in the same place. If not, adjust the stop rail adjustment accordingly. .