By Vince Mrykalo, Technical Editor of MPT
Remove action, vacuum out the key bed, tighten all screws, remove stack and keys, vacuum key-frame and blow out the dirt from the stack. Now travel every shank, checking all shanks that you remove to paper, for center pin looseness as well, and re-pin as necessary. Then straighten all leaning hammers by heating the shanks, also known as burning hammers. At this point, don’t worry about re-pinning other hammer flanges yet. Reshape the hammers and vacuum up the felt. Re-assemble and reinsert the action back into the piano.
1. Bed the key-frame
Bring all glide bolts up off the key-bed, and after bedding the back rail and then the front rail: Make sure all glide bolts are seated (not knocking). Do this by lifting up at the let-off rail with your fingers while tapping at each glide bolt stud. Do each glide boltone at a time while lifting near the glide bolt at the let-off rail. You should usemoderate lifting force before you hear a knock (which would be the glide liftingoff the key-bed). Each glide should require the same amount of force before youhear the knock. Start with the second glide from the left and work your way up andthen go back to the first one.
2. Take three key dip measurements
At C1, C4, and C7, write down the measurements. The reason for this is that whenyou have the action on the bench, you can fairly accurately recreate the key-bedprofile which is important for more accurate bench regulation. If the dip is too shallow with the action on the bench, put some cardboard punchings or strips under the glides until the dip is deep enough. Too shallow, and you can add punchings/strips under the front rail or front and back rail, until the desired dip is had.
3. Align hammers to strings
So that the left side of each hammer protrudes only 1/16” past the left most string.Test alignment with una-corda pedal depressed.
4. Regulate let-off
Let-off the hammers as close to the strings as you think is expedient.
Take action to shop (or if doing this in the home, remove action to a table).
- Check all action centers, especially the rest of the hammer flange centers. Usually many are too loose. A quick way to determine looseness is to bring about four hammers up off the cushions at a time and let them drop back to the cushions on their own. (I bring them up to about 70 degrees from level, then let them drop) Compare to those centers that have already been re-pinned. Remove the one(s) that bounced the most and test those for looseness (no more than 6 swings) and re-pin if necessary. Re-pin those that are too tight as well. In Steinways, older ones (pre-teflon) often have centers that are too tight, usually due to varying degrees of verdigris. If it is present, then you must clean all the verdigris out before you can proceed. Also check for verdigris in the jack and wippen flange centers if it is in the hammer flanges.
- You then MUST clean out any funky “lubrication” that is found in the repetition spring grooves in the butterfly-type underneath the repetition (balancier) levers. Otherwise regulating the springs is almost impossible! You can use a little soft pencil lead both to clean out the grooves and re-lubricate them all in one shot. Then polish the spring ends that ride in the grooves and you are almost finished with the preliminaries.
- Treat key bushings with Pianotek concoction (Get some. It really works. Call Pianotek for it). Also treat, if necessary, balance holes for chucking.
- Align wippens to knuckles, and tighten wippen flange screws.
- Two more things before starting your regulation: make sure all the shanks are up off the cushions, and the keys are level. Steinway likes to have a slight crown to the level of the keys, but that is not necessary.
Now, the Regulation
- Let-off (which has already been done).
- Jack-to-knuckle alignment.
- Back checks adjusted to check as high as possible without rubbing hammer tails on the way up.
- Springs strong enough for a sure hammer lift, but not jumpy.
- Jack height in window (check by winking). Jacks should rub slightly on knuckle, but must not hang up on return (don’t flip jack back in order to cause it to return completely; it should return on its own accord).
- Drop. Make it simultaneously happen when let-off happens.
- Blow. Do this step after returning to the piano. Adjust to 45-47mm, and at the same time, so that the shanks are not more than 7/32” off the cushions, or if hammers are worn, go by how high the shanks are off the cushions: they should be no more than 7/32” off.
- Dip/after-touch. This should be done as the last step while at the piano. Adjust dip so that you get desired after-touch.