Tuning a piano is only the first step in ensuring its proper function and performance. A piano action is made up of thousands of parts, all of which form a system that must be timed or regulated, like a clock or a car engine, if the parts are not adjusted correctly, the result will not be satisfactory.
Regulation includes a number of adjustments and could include, but is not limited to:
Bed key frame, adjust endblocks for proper hammer strike point
Regulate keyframe glides
Square and space keys
Level keys
Regulate key dip
Travel hammers, shim as needed
Align hammers to strings
Regulate the una corda pedal (soft pedal)
Align whippens to hammers
Regulate jacks to knuckles
Regulate height of repetition levers
Regulate hammer height
Regulate hammer rail height
Regulate letoff
Regulate hammer drop depth
Regulate dampers
Regulate backchecks
Regulate height of damper stop rail
Regulate damper pedal and sostenuto pedal (middle)