Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum DIY Grand Piano Action recondition and regulation

Wanted to see if I could potentially get some feedback or help. I've played the piano a few times this week to test things out. While I don't have much experience playing on a grand action, I feel like mine isn't perfect yet. One of the pieces I used to play is Beethoven Moonlight Sonata 1st movement. When playing the left hand chords soft / slow, I can feel the left off / escapement. This doesn't happen when playing the note/key every time. It seems to only happen when I play the key soft on very slow depress.

I double checked let off (a bit more than 2mm), checked that when moving the jack heel that the hammer barely moves and drop is around 4 mm.

Could it be possible that I need to move the jack a bit forward (towards the player)? I was also thinking it could be from the hammer blow distance being far from factory since the hammer felt has been shaved quite a bit and the knuckle leather was shaved down as well. I'm sure that changed the overall geometry. I do plan to purchase new hammers & shanks in the next few months. However, I would like to know if I have something a bit off in the regulation at this point.

Thanks for any help.

It's normal to be able to feel let off when you press the key slowly, whether you are on a grand or an upright. Try grabbing the front of the key top between your thumb and first finger and move the key all the way through its motion. As you depress the key, you will feel a tiny bit of lost motion (upright only) then you can feel the damper begin to lift, then you'll feel let off, and finally a little bit of aftertouch before the key bottoms out. If you do this slowly enough, the hammer will not even hit the strings. If you pull up on the key from its rest position, you'll get a little bit of motion before the key hits the key upstop rail (grand) or the nameboard felt (upright).

This all assumes the action is not too far out of regulation.

I would say that my action works as described in the above post. I slowly played the lower portion of the keyboard (A0 - G3) note by note. There are 4 keys that I labeled last night that don't play through as smoothly. While I did expect this seeing the level of work that I performed, I'm sure it's just a regulation step that needs a bit more attention on those keys. I'll pull the action out this weekend and take a look at those few keys that don't feel quite right.

Matt, I never notice letoff when I play soft passages. Could be you're more sensitive. Mechanically, I would think it has to do with the friction of the top of the jack against the bottom of the knuckle. Have you lubricated the knuckle? Rubbing PTFE powder onto the knuckles should smooth things out a lot.

I don't think that it's me. I play my other piano (antique Chickering) and don't feel it at all. The knuckles were treated with PTFE powder while I was re-assembling the action. I'm going to pull the action out in a few hours and inspect the few keys that I labeled. I have 4 that feel a bit different than the rest. I'll post my findings once I take a closer look.

I seem to remember that you sanded your knuckles to get rid of the groove/flat worn in by the jack tops.

It seems to me that sanding out the grooves in the knuckles would necessarily flatten the contact surface of the knuckle somewhat, resulting in a change from a perfectly round arc/path for the jack-to-knuckle contact point to a path more like a right angle. Even though the wear you corrected would have already done this somewhat, the sanding may have increased the loss of material from the knuckle surface. It seems like modifying the original contact point arc to a more flat-to-angle configuration could translate to a different feel during the keystroke. The initial part of the keystroke, where the jack top is traveling across the new flat, would be characterized by resistance. And this followed by a more sudden, letoff when the jack reaches the end of its new path. This might feel substantially different than the original, gradual movement of the contact point around the perfect arc of the original knuckle shape.

Perhaps, if your knuckles look noticeably flat from the sanding, you could exchange the wippen assembly with one from the end of the keyboard where sanding was likely a lot less (and the knuckle therefore, is much rounder, as original) and see if that does anything to restore the feel.

The knuckles are absolutely worn and need to be replaced. The hammers as well have surpassed their service life. At this point, my hope/goal was to get the piano to a point where it's far more playable than it was. With that said, I would say without a doubt that I have far exceeded my own expectations. The piano plays worlds better than it did when I purchased it.

So, at this point, I want to make sure that everything is as good as it will be until I can purchased and install new hammers & shanks. The noise is completely gone from the action which was pretty bad before. You could hear the mechanical aspect of the action over normal playing. Now the action is near dead silent and very smooth, aside from the few keys that have this odd let-off feeling, which very well may be the knuckles.

I have an appointment on March 23rd with Piano Craft to spend a few hours on the piano. I'm sure their tech will be able to put some solid work in and give me some feedback on how bad or good I did with the action reconditioning.

This post will most likely be one of the final ones in this thread. What a time it has been learning so much! First and foremost I would like to say THANK YOU(!!) to everyone that has helped me with this project. It has proven to be much more work than I initially thought. However, with the right DIY mindset and professionals to help along the way, anything is possible. So again, thank you!

Now to the update. Noah from Piano Craft came out for our scheduled appointment yesterday (March 23rd). When the appointment was set, we discussed that I would like a few hours of his time and if we make it to a tune, that would be good, however not necessary.

Noah arrived a few minutes early and we discussed the goals for the day. Noah is the tech who repaired my flange bushing so he was a bit aware of what was going on. Upon inspecting the action in the piano and measuring all of the critical items, I was pleased to hear that I did a really good job, especially for my first action. There were a few issues I left in place before the appointment as I didn't know what do. There were a few notes that were double striking and a few that felt clunky.

The first thing he noticed was I went a bit too tight on the key pin holes in the bottom of the keys. He eased most of the keys while showing me in great detail how it should be done. After that he pointed out the while I did work the knuckles, there were shot, which I knew. He bolstered one of them as a test and that particular key does play a bit smoother. He also pointed out the clunky feeling I feel in a few of the keys is absolutely the worn knuckles and no bit of regulation will make that feel right. Hands down it needs hammers and knuckles, again, which I knew.

The other thing he point out was I had a bit too much aftertouch on a majority of the piano. How he explained how you measure it made so much more sense than to just measure key dip. We measured around .070-.080 on a few test/sample keys. At which point he showed me how to properly set and check aftertouch along with key dip. The aftertouch being too much on a few keys was causing the hammer to rise too high after letoff, causing a double strike. That was resolved on the key where he showed me how to check and properly set aftertouch.

The last few things he mentioned was that letoff was perfect, drop was right and overall, everything looked really good.

So now I have a few items to set. Aftertouch will be set and done today. He advised that I soften up a few of the repetition springs as they were a bit too spirited. In the near future I will be purchasing new Yamaha shanks & hammers. I'm going to install them then have Noah come back for another appointment to voice the new hammers and tune the piano.

Thank again for all of your help!!
Matt

👍👍

Pwg

Matt, thanks for sharing your ongoing learning process. It has been incredibly valuable to me (and others, I assume).