Side play refers to the side-to-side movement, rocking, or ‘wiggle’ that occurs on keys when the key bushings have loosened over time. Adjusting it is a part of keyboard regulation along with key spacing, key squaring, and key height and key dip adjustment.
On new pianos there should be very little side play of the key. Over time however key bushing felts become worn and a gap can form between the bushing and the balance rail pin and front rail pin. This can lead to the key moving around when played, at best looking uneven and at worst rubbing against other keys or causing keys to stick.
Sideplay is adjusted on acoustic, Rhodes and Wurlitzer pianos; and can be adjusted in one of three ways:
- Using a key spacing tool twist the front rail pin either clockwise or anticlockwise to increase the amount of pin diameter that touches the key bushing. If turned too far, this will cause a sticking key. Turn the pin back until the motion is slight and not sticking.
- Using a pin tightening tool to tighten the mortise of the key. This is done by inserting the tool into the key mortise and tapping the top of the tool with a hammer. This will reduce the size of the mortise and therefore tighten the gap. Again, if overdone this can cause a sticking key. Ease the key with key easing pliers if this occurs.
- If some keys are really bad, then rebushing keys is the most effective option. This is also essential if key bushings are missing. This process is discussed in a seperate post.
Sideplay issues can be frustrating for pianists as it can cause keys to rub and make unwelcome noises. Correctly adjusting it will aid in a greater responsiveness of the key.
