Removing/Installing Actions of Earlier Pianos
Removing/Reinstalling Actions without Support Sleds
Earlier Viennese pianos with ranges of from 5 to 6 octaves do not have a removable batten holding the action in place. What appears to be a batten is actually the front of the action itself. With this type of action, the brass acorns are indeed to be used to pull the action out, but only to get it started moving. Notice how the fingers are used to restrain the action while the thumb pulls on the acorn.
As soon as the action begins to descend, you should support it by slipping your fingers under the front rail. In this manner, you can control the descent of the front, making sure the action doesn't rapidly drop, in which case hammers will bounce up and break on the wrestplank. Once the action has descended to the bottom of the keywell, you can proceed in the same manner as with the larger, later actions.
Removing/Reinstalling Actions with Support Sleds
Many south-German instruments and some Viennese pianos have a separate sliding framework - called a sled - which sits underneath the action. To remove these actions, you must first pull the sled out completely, allowing the action to drop to the bottom of the keywell.
Here, harpsichordist/fortepianist Siebe Henstra demonstrates how to remove the sled on his original anonymous 5 octave instrument. Begin by pulling the sled out from any place you can get a good grip upon it. It you have to reach under the keys, be careful not to actually lift a key up, or its hammer will surely catch on the underside of the wrestplank when you slide the action out later. Note also how Siebe is keeping the action itself in the instrument by pushing against the end blocks with his thumbs.
When the sled has come out far enough that the back of the action can drop, it is especially important to keep the action in the instrument while the sled is removed. When the sled is almost out, grab the front rail of the action to hold it up while removing the sled with the other hand. Then the action can lowered, and after checking for any hammers which are not resting on their keys, the action can be slid out of the instrument.
To get the sled back in, simply lift the action at the front and slide the sled in underneath it. The sled is pushed in until it jams against the action, at which point the end blocks are pushed downward, rotating the back of the action upward, after which the sled can be pushed in all the way.
Note
If you choose to follow any of the advice or instructions given here, you do so COMPLETELY AT YOUR OWN RISK. Paul Poletti assumes no liability whatsoever for any damage to any instrument nor for any injury to yourself or others.