upright pinblock replacement.

[Newton Hunt]

"Why the 7º angle on the tuning pins?"

In a grand piano the angle for drilling a pin block is determined by the
height of the bearing bar such that the pin is at 90 degrees to the
string when the bottom coil is 1/8" from the plate.

In a vertical piano this is complicated by the unknown height (unless
carefully measured before hand) of the pressure bar when assembly and
tuning is complete.

If the angles are wrong the string will tend to want to ride down the
pin or ride over the next coil up.

Hope this mystifies all.

        Newton