More than a few piano technicians like to use hard blows. Hard blows are a good way to confirm a stable tuning, but they are damaging to ear, joints and piano. They also can annoy the customer.
This video shows how some technicians use hard blows; by tuning slightly sharp and then banging the pitch down.
The video also describes an embarrassing situation where my tuning was not stable and helped me to realize one important reason why you might need to use hard blows.
If you've watched lessons 10/11/12...
