Hocus pocus All your DW measurements are based on wacking the stack with your hand Tolerances no more refined than + or- 5 grams

I've never used this method myself - nor have I ever seen this done in this this way before. Moreover, my copy of the piano tuner's 'bible' - Reblitz - makes no mention of this either. I guess I'd have to try it for myself in order to see if it actually works. My own method is as described by Arthur Reblitz, using a hand-held sanding block. I should add that I have 46 years' experience working as a piano tuner/technician.

I belive, Steinway T-short may help to make good job!

This is a brilliant video!

Tienes las medidas para reproducir?

Your Magic line is wrong, on the line it's not the half capstan, but it should be the point of contact between the capstan and the wippen heel cushion.

Love it. Looks great and I can see you have a lot of experience. But still I wonder why so many people use this method while having such great jigs (like the hammer hanging jig of spurlock).

This was the most throughout and ordered explanation I have seen of this marvelous mechanism. Many thanks to you, for explaining so well something that was making me scratch my head so much.

Be cautious about adding too much weight to the keys. It not only changes key weight, it also increases the mass of the key. This affects inertia and slows repetition. There are other techniques for changing touch weight without increasing key mass.

Really fascinating. I own a Bluthner X (230 cm) and its action needs to be adjusted, so I am looking for information what will be done by the technician. I just like to get a general idea, what they have to do. Your method seems to be really interesting and precise. The up-weight is 28 g, the down-weight is 46, the exact center is the balance weight of 37 g. The distance from up to ballance or from down to ballance is 9 g and that is the friction. Here is what I do not fully understand. As far as I (a rather untalented hobby player) know from personal experience, the down-weight must be perfectly even (either exactly the same weight everywhere or - as Steinway does it with a very small decrease from base to trebble). But the up-weight is actually a result of the desired down-weight, let's stick with the 46 g you set up here, and the friction. At a quick glance I saw numbers of 8 to 12 g friction written on your hammers. So looking at the 12 g friction key: with your down-weight of 46 g you would have an up-weight of 22 g, resulting at a ballance weight of 34 g At the 8 g friction key you will have a down-weight of 46 g, an upweight of 30 g and a ballance weight of 38 g. In the end I do not understand, why the ballance weight is so relevant, if it still is different from key to key based on different friction. If of course your method would be to even out friction first (equal friction = equal ballance), I would understand the ballance purpose. My piano technician btw told me, he will replace at my action what needs to be replaced. Then he will adjust it as well as he can. And then he will adjust the down-weight to my liking with leading with the general restriction, that no up-weight must be below 20 or 22 g.

Hello, how many meters of keybushing felt do you use to replace all of it?

Thank you for the great description. That is really interesting , The person who made this mechanism several centuries ago was really a genius

Fantastic presentation. Wish I had this much detail given to me 10 years ago. Thank you Sir !

what do you use to measure the friction of the hammer ??

1:15 Absolutely valid point, but there are still some remarkable pianists that I have spotted doing this, Seong-Jin Cho for example comes to mind. Tremendous technique and I highly doubt he doesn't know it's pointless for achieving "vibrato". I reckon some might do it to force the finger to be relaxed instead of tensing up when holding a note?! Just an idea 😄 Thank you for this video!

Nooooo! All 3 legs on FIRST, pedals on AFTERWARD. Tipping a piano over on the lyre is the lazy way and harmful to the mechanism and structure.. I'm glad these movers are nowhere near where i live.

let s say alleluha to the Lord cause of you and your epic tutorial🎉

An obvious question: Does this work for upright pianos? Not everyone has a grand piano.

Hi Bob! Great videos! I worked with you and Ken Sloan in the tech shop at Oberlin in 1984 as Steinway began the hammer updates. Good to see you again!

WOW, this is so fine. With this knowledge, one could build the pyramids! Thanks for posting. I was just looking for info (I found) on replacing ivory/plastic key tops and saw this 'Weighing' video related. I'm glad I watched - with your enthusiasm and clarity, I now want to get into 'weighing' my good ole Kawai upright! This makes it interesting and clear. Many thanks!

Good video Robert! Have you tried Durhams hard putty? I just plugged a set and it was very fast. I’ve always used wood plugs but this seemed to work well and didn’t shrink. Weight is similar to wood and it looks good. Very good videos by the way! Thanks. J

Getting my regulating tools tomorrow and I'm going to be studying piano regulation and tuning. I need to get an action model. This was extremely helpful in understanding how a grand action works! Fascinating and very educational. Thanks for posting this.

300 years of piano building! Are You telling me, these parts, You have so nicely demonstrated, are, basically standard parts? Big or small pianos?

This video is great ! Thank you so much

This method is NOT about achieving even Down Weight. The point of this method is to achieve even Balance Weight! Also, I think you are basing your comment about the number of leads from your observation of those leads sitting atop the keys only. These are leads that I added to existing leads in the keys, so you don't get a picture of the even distribution of the leads at the conclusion of the effort. Additionally, lead plugs have different sizes and weights, so the total amount of lead is actually pretty consistent from key to key. The resulting inertia is pretty consistent from key to key. The bottom line is that if you achieve an even Balance Weight, the other physical considerations fall into line: a discernable key leading pattern and inertia naturally follow. Lastly, I should point out that this is a RE-leading job. I had to make certain compromises, such as the different sized leads, in order to not have to remove and plug an excessive number of original leads. This keyboard started out with 5 and 6 leads in the bass, four in the middle, three in capo #1, and and two leads in capo #2 all the way up to note 88! In the end, I balanced it such that the result was three leads in the bass, two leads in the middle of the piano, one lead throughout most of the capo section of the keyboard, and I only had to back-lead two keys! I did not have the option to replace the original keyframe and keys with a new keyframe and keys. Were that the case, I could have stuck with one size of lead and achieved a cleaner leading pattern from the start. I hope this helps you to better understand what I undertook to do with this particular set of keys.

Such a cool technical video!

What a fantastic video. You are a great instructor. The pacing of each individual explanation of components was spot on. Thanks for taking the time to make this.

But it's NOT balanced. You can tell just by looking at the leads. For example one key has one lead and a neighbor has two leads. That means the inertia is all over the place too. So you might get the downweight even, but its at the expense of every other parameter.

Austin C. “the claim that you are only talking about vibrato” …… I think you should re-listen to that part of the video again. He says exactly that he is talking about the desire to add vibrato by wiggling a finger on the depressed key. I’m not sure why you are having difficulty hearing and remembering his exact words and then claiming he said something else. After all, you can re-play the video all you want to get the details down if you need to instead of twisting things to make your own unrelated claim.

The reason the design is what it is is due to evolution. Rather than start from scratch when there is a new problem or a new understanding one adapts. Through the process of evolution small changes can add up to a significant effect. One can easily accomplish the same effect fewer parts but requiring more complexity and modern tech. This is basic systems engineering. There are only two things going on, the hammer hitting the string(simple impulse theory which is extremely simple and straight forward) and then the performance aspects which is in the area of optimization and fine tuning. A lot of man hours were put in to adapt early primitive designs which handled the main effect(that of making a sound) in to adding a benefit to either sound quality or performance quality. In fact there were many extension that were lost yet were actually beneficial(but not popular to the masses) or detrimental. There's many ways to skin a cat.

A lot of this at the start is nonsense. One doesn't have to have a clue on how something works internally to know how to use it externally. Look at all the people who drive cars, 99% have no clue how a car really works. In fact, you don't have to know how something works to know how to use it. That is kinda the point in some sense. If we did we could never get anywhere in life as we would have to learn everything to the infinite degree just to use it effectively. Sure, knowing how something works internally can speed up learning in some ways and cases and such but given the amount of time a piano player practices it is almost surely that they will develop an internal feel for what is going on with never truly knowing the details. There really is very little a pianist can do to a key. He just moves his finger down. All the "action" is translated in to how he perceives the effect which we call "staccato", "legato", "accent", etc. Hence why a child can play a Mozart sonata extremely well without having any idea of mechanics. As far as "vibrato" holding down a key, as an example, it is irrelevant if a pianist thinks he is modifying the sound when he is not. If it makes him feel better then so be it. If he plays better thinking that way then so be it. If a person actually knew music performance they would know that anything that enhances performance, feel, etc is not silly and ineffectual. Don't get me wrong, I think it's always important to learn as much as one can as it can only help(well, almost surely). I'm simply saying that as humans we do not need to understand the details of how something works to take full advantage of it's capabilities. Practice teaches us how things work in "metaphor". With enough playing and awareness one can figure out the true nature of how the mechanism works for piano playing and understand it far better the an any engineer that does not know how to play even without a clue about levers, springs, escapement, etc.

I totally disagree that there is no function for holding a key down after the hammer has already struck. It helps the pianist to maintain the weight and force required to make the next note match. But... You master technicians like to claim that you are master pianists. And vice versa. We should all maintain some humility to accept that we don't understand everything.

Thank you so much! Every single time I am amazed at how incredibly all the parts of the action are interacting to create a flawless performance! Without all this effort being put into creating a perfect action, and without the technicians to make it work perfectly well, pianist would not exist! Thank you again!

Hi Robert my piano cant make repeated notes that well, Is there a way to make piano make repeated notes better?

Damn, this is insanely educational. I just bought a used piano off craigslist and want to renew it myself. This was a great, id-depth crash course in how piano action works. Cheers!

What is the purpose of the let off? The one part I don't understand.

Wonderful video. This musician turned engineer enjoyed it very much and learned a lot. (BFA Music Performance and BSEE) .

thanks...worked out great. Not sure why the RPT's scare people from doing this; although, it does take skill

Many thanks teacher.

Thank you very much the best online teacher.

Wow there sure is a plethora of useful information here for an aspiring piano tech.

Thanks! Great Video. I sneezed all the way through it just watching that felt dust!

Exactly what I was looking for....I am an engineer....so have to know how it works !!

I looked for the longest video about piano action hoping it would cover all the technical details and boy did you deliver. This is tremendous!

Hello Robert, thanks for your video. I am looking for information which I cannot find in any books or videos I have been watching, so I'm seeking your advice please. I am rebuilding a 6' Bechstein Grand. I had a company replace all the hammers and glued new shanks. Now that these hammer/shank assembly have been reinstalled, I need to check the travel of each hammer to the strings. Before doing this, should the hammers be vertical to the strng, then set the travel or is it more important to make sure that the hammers strike the string at 90 degrees? I have set the hammer AO vertical, but when lifting to the string, there is side travel. Before setting this hammer vertically, there was less side travel. This confuses me. Where do I start...? Thanks for your help

What is the standard length of the key are they varies concert piano grand piano and baby grand piano?

It's a butcher job without meat.

Why so complicated? what all the intermediate levers? couldn't you rest the hammer roller directly on the capstan, to create an up/down motion more directly?

That was incredibly insightful. You're a great teacher!

This is fantastic. An extremely lucid and thorough explanation of the mechanism.