The Fascinating World Inside of a Piano

I've been playing the piano for over 20

years now and I realized that beyond

understanding the very basic the very

surface levels of how a piano works I'm

quite clueless so recently I decided to

change that and I tagged down one of the

best piano technicians I know his name

is Damon groves and I asked him a bunch

of questions so this video will be

organized by the questions I asked him

so I suggest that you use the time

stamps that I will provide in order to

navigate the different sections of the

video so without further ado here's

information and I hope it's as useful to

you as it was for me

so I'm here with Damon and he's going to

show us some things about


okay so the key key has a front rail

mortise the front rail bushing is got a

key top it's got key led it has a

balance hole mortise of balance whole

balance bushing as a capstan the key end

the cushion as a jack as a jack Center

Jack regulating screw repetition lever

repetition spring repetition Center

repetition height adjustment and let off

button the leadoff rail hammer rail

hammer flange hammer shank a knuckle

hammer flange Center the hammer has

never felt in the hammer core the back

check in that check buckskin you have

the damper lever damper weight so you

have a damper capstan you have a soft

NATO tab you have a damper block a

damper screw a damper wire damper felt

damper head and the drop screw something

like that


the key is one lever the wippen is

another lever this black piece and then

your hammer

and hammer shank is another leaver so

it's basically three leavers the key the

wippen and the hammer shake so this

brass capstan of the key pushes the

weapon up which in turn pushes the

hammer shank up towards the string the

voicing is essentially working with

hammers and strings to better optimize

sound so you want clarity projection and

power you want dynamic range you you

want to have the triple peas and the

triple FS and hopefully everywhere in

between and then there's also evenness

so you want to go from note to note or

from you know base to treble and have a

balance and evenness you have the hammer

that strikes the string the flatter it

is the more issues you probably have

with tone it's not very clear you don't

have dynamics and a lot of times it

becomes pretty harsh one of the things

that we do is reshape the hammer and we

use either strips like this sandpaper or

we can use files like this and we're

removing felt in order to sort of

restore the original shape of the hammer

because it's been distorted through

planes sometimes little shoe shine

so that's shape and of course the hammer

needs to be flat because when it strikes

the strings it needs to strike all three

strings the other thing we do as far as

voicing is needling so there are a lot

of voicing tools that have you know like

torture tools needles these are sewing

needles but it's in a tool and I can

adjust the length of the needles some

tools have one needle some tools have

you know six or seven the felt on a

hammer is under a lot of tension and

compression it's the sort of natural

design of the hammer so if say we had a

piano that was really harsh and bright

usually the Hammers too hard and a way

to solve that is to needle the hammer so

we can we can needle the hammer here in

the lower shoulder or the battery and

what I'm doing is changing the tension

and the closer and closer we get to what

we call the strike point which is where

the hammer strikes the string the more

drastic our needling becomes as far as

tone it's like almost giving the hammer

to massage if if a hammer is too dense

too rigid it doesn't put its energy into

the string it'll basically just hit the

string and rebound off the string what

you want is that hammer to sort of

compress and then push energy into the

string that's where power is from powers

not from like having something really

hard it's from having the proper energy

being sort of transferred into the

string and you occasionally you break a


and you'll have to retrieve it from the

hammer yeah at first so there there's

reshaping there's needling there's

fitting so we're making sure that when

this hammer strikes the string it's

striking all three strings at the same

time most notes have three strings and

there is you could add chemicals or

hardener so if a piano wasn't dense or

sorry if a hammer wasn't dense enough

and didn't have enough tone built up and

it was really muffled you can add a

chemical like lacquer or plastic

dissolved in acetone and you could add

it to the hammer on top ah it depends

you can add it right on top of the

strike point which will give you that

attack that's the immediate attack or

you can if the hammer is really soft and

lacking some backbone you can put the

chemical in the shoulders of the hammer

we call it


as you can see I'm pushing the key down

and the hammer is rising towards the

string but just before the hammer

touches the string it escapes in there

and that's crucial if that didn't happen

the hammer would touch the string strike

the string and then stay in contact with

the string which is not good so there's

some mechanism that creates this

escapement or let off we call it where

it dips back down yeah and if you do

this on a piano and upright or and you

key down very slowly you can feel that

you can feel the escapement it's a

little bump for lack of a better term so

the jack is actually pushing the knuckle

up which pushes the hammer up the jack

touches this we call it a let off button

which causes the jack to pivot which

causes the hammer to escape or drop away

from the string what about this part

here so at the end of the key that's the

end of the key here and that's called

the key NFL and it's a job is to lift up

the damper so the damper obviously

silences the string when it's not in use

but when you play the key the back end

of the key actually lifts the damper off

the string so that the string is free to

vibrate and of course when you let go of

the key the key end goes down the damper

lever goes down

and your damper then does its job and it

dampens the string I'm vibrating and in

this picture here where's the pedal this

aluminum piece on this peon is called

the damper tray and it moves every

single damper up and down so when you

push the damper pedal you're a lifting

every single tamper with the tray with a

tray so every damper is lifting off the

string anywhere where there is some sort

of fell to cloth the hammer this hammers

brand-new it has a nice shape to it

after thousands and thousands of

repeated playing the top of the hammer

actually get flat so when it hits the

string so much the shape of the hammer

becomes flat on top and you lose some


you probably have a harsher tone the

knuckle also kind of flattens out

because you see here it's being pushed

up so the knuckle gets flat how would

you fix that place it you can replace


ya can do some maintenance but you can

you can replace knuckles yeah the

Hammers you can put new hammers on if

you file them and remove too much felt

after years you can put Amazon you can

put new hammer shanks your knuckles you

can replace weapons this is a hammer

rest cloth you can replace that and you

see anywhere where there is a piece of

cloth it'll compress due to wear and

tear and so that's why making these

adjustments here is really important as



regarding maintenance what's the ideal

temperature for a piano to live in

humidity level so the ideal situation is

in room temperature and somewhere around

40% humidity the temperature is assuming

it's you know not extreme like 30

degrees or 120 reason it is not as

important as humidity okay

relative humidity so in depending on

where you live in the seasons and the

cycle if you have really humid summers

and really dry winters where the heat

comes on that's an issue

it's those seasonal extremes that will

really cause havoc on your piano don't

cause you can to go out of tune it might

cause structural issues because this

instrument is mainly comprised of wood

get a hydrometer that's a really good

it's usually a digital readout of your

relative humidity okay so high-drama

hygrometer oh yeah it'll tell you the

temperature and humidity don't put your

piano near like a heat register or

something that pumps out a lot of heat a

fireplace air conditioner um I think

that's okay only because again if the

space isn't being usually teet sources

that we worry about because they dry the

piano out a lot a radiator

we know he's register windows it's up

and down meaning as sunlight is is one

thing that doesn't affect the tuning and

instability as much it might fade the

the case like your black piano you'll

to get after years like faded smokey

look something that I noticed in

friend's apartment in small studio type

apartments where perhaps the kitchen is

in an open space and the piano is in the

other side of the room but it's pretty

close and they like to cook or they like

to fry things it affects the air and it

affects the piano it does

thank you boy making a big pot of water

for posture so kind of that you're

making that humidity like spike and I

have seen some pianos that are kind of

greasy and oily like yeah this ladder

like it's you know five feet away from

the kitchen yeah and it's a little gross

which I see though the oil

yep yep so there's a brass pin the metal

part and then there's a cloth Center

around it and it's like a hinge or a

bearing mm-hmm those are where all the

parts pivot there's one here for the

jack they can get worn out they can

actually they can seize they can be

tight too tight and that would cause the

piano action to be heavier or they can

be too loose and have too little

friction and it could cause the action

to feel lighter and you lose a bit of

control what would you do to make it

have more friction or less friction so

if say this Center was too tight and it

was too too difficult on you you're

having to put too much force to lift

this hammer

there are basically two options you can

lubricate it so the you can lubricate

the felt or this pin you can replace

with a bigger one

yeah bigger or smaller yeah how do you

take that with it

a tool that kind of looks like a torture

device I don't have it with me but I

could show you it's it's a punch so it's

got a tiny little pin on it and you

punch the brass center pin out another

way to make it heavier is to add weights

right yes we're talking about weight

I mean friction is a big part of how the

action feels so if you if your friction

the parts that create friction are all

adjusted almost every key and a piano

has some sort of lead weight so this key

has to lead weights and it's to counter

the weight of the hammer essentially you

could have larger hammers or well

lighter hammers are heavier hammers and

it's usually counter balanced by weights

in the key so if you wanted to have a

lighter action you could put a lead

weight add a lead weight which would

help you play the key

the only concern is that when I played a

key and I want the key to come back up

which you do very quickly in order to

repeat to know if you have too much lead

here the key is going to be a little

sluggish coming back up so it's heavier

but it's not it's a it's a weird thing

yeah the the touch might feel heavier

but the key might actually be slower and

returning so the best way to make it

feel heavier would be to address things

here you can't thank you yes you can add

weight to your hammer head I could do

that how would you do that you could get

a new hammer that's heavier or you can

and I've done this you can actually

drill a hole in the hammer molding which

is the wooden part of the hammer

and insert a piece of lead solder solder


you're not soldering it's just lead okay

so you drill a little you put this piece

of lead in there you kind of squeeze the

lead so that it doesn't wobble out and

you've added you know half a gram or

something to your hammer which

translates to it's like a five to one

ratio so if you add half a gram to your

hammer you're going to add about two and

a half grams to your touch weight or

your down weight because the way it

works is basically like a five to one

ratio this piano is clean this this is

like as good as it gets don't clean the

piano but inside the piano like leave

the strings and the dampers alone you

can wipe off the keys and the case and

stuff like that but I don't you don't

need to clean the strings or get in

there and dust is like when you bring

your tuner your technician over have

them do that we have special tools I

wouldn't want a piano owner to mess

something up take a towel yeah yeah dust

it off dust it off damage your dampers

or you know clean the strings with some

sort of liquid cleaner or something like

gonna win taxes what about outside of

the piano um the best thing is just to

well to dust it if it gets dusty with

like a feather dozen or something soft

if you have streaks like handprints or

something on it you can use a soft

cotton cloth

you can wet it with just a little bit of

water like damp okay not wet but damp

and even a little bit of like a hand

detergent thinking this is something to

kind of cut the you know the grease and

stuff like that it depends so I think

certain factories put more effort into

the finished product where you wouldn't

have much to do in the first couple

weeks or months or something depending

on how much it's being played but other

other pianos have maybe a little bit

more finishing work to do or say you

play a piano in a showroom or somewhere

and it sounds really really nice you

bring it home and to put it in a corner

of a room and it sounds different that

happens a lot so oftentimes pianos do

need to be voiced for their environment

so if you have a really really big piano

in a small room it could be overwhelming

and you can try to sort of mellow it

down give it a little sweeter tone you

don't need like it certo piano in yeah

yeah unless your living room is

ridiculously big

you do have to realize that a certain

instrument in a certain space has its

intrinsic qualities that you don't want

to change too much yeah so there's

there's a line they sometimes you can't

cross but there are there are things

that you can do to make every one of

those pianos feel more comfortable buggy

cute not mine

yeah I mean I took a pencil out of this

earlier and my thumb

sandwiches and uncooked pasta there's

two paper clips in there yeah there yeah

yeah sure

yeah ain't hurt nobody yeah I have it

tuned regularly uh-huh like every year

maybe once a year yeah oh we well that's

not a piano you don't maybe use so much

like if it's kind of a piece of

furniture and you're not playing it

every year like once a years fine okay

for you uh-huh

more often I don't know twice a year

three times a year four times a year

something like that but regularly so it

doesn't skip a whole year or most

seasons without being maintained

the challenge in designing pianos is

with designing smaller pianos because

you're compromising with the length of

the keys with the length of the strings

that's a compromise designing a really

good nine-foot piano is well it's a

challenge but it's not compromised say

say you ever like this is a fairly small

grand piano and if you were to compare

this to a nine foot a concert grand

piano your highest notes 88 - probably

somewhere over here so just above middle

C that hardly changes mm-hmm so the

string lengths are really very similar

mhm it's when you get you know to middle

C and below that you get much longer

string lengths and much longer bass

strings that the three factors of pitch

are length diameter and tension mm-hmm

so to compensate for a shorter length

you have to have more mass or thicker

yeah it would affect a little bit of the

action because smaller piano smaller

grand pianos the keys are shorter so if

you have larger pianos like 7 foot 9

foot pianos the keys are longer which is

a distinct advantage to the pianist okay

because there's you have more leverage

and when you look at your hand position

you're playing some keys much closer to

the balance point oh because it's easier

to play always on the edge yes yes so if

you have a shorter key then the

difference between playing here versus

playing here is quite drastic because

you're moving much closer to the balance

point of the key if you have a longer

key where the balance point is further

away yes and the difference between here

playing here in the key in here in the

key is less because you have a lot more

leverage does that make sense yeah okay

like there's light that one I never

thought of it yeah so if you play small

tiny little upright pianos hmm the keys

are like the entire key is really short

but if you up to a 7-foot piano you have

longer keys and a 90-foot piano probably

even longer keys

the usual advice that I give to people

looking to purchase piano especially

secondhand pianos is I mean give

yourself a lot of time mm-hmm you don't

want to make a rushed decision and then

maybe regret it you want to try a bunch

of different pianos not to the point

where you get sort of overwhelmed and

confused but to the point where like

once you sit down and you and you play a

piano you you kind of know very quickly

this I like this piano so time is was

really crucial the other thing is if it

is a second-hand piano have a piano

tuner technician check it out so if you

really like piano you know and you're

going to spend whatever huh you know

hundreds thousands of dollars hire

someone for an hour whatever just to

look at the piano to make sure there's

no structural issues to make sure

there's something that you know you

maybe you'd have to replace the Hammers

in a year so just just so you know sort

of what to expect and there's no sort of

major flaws other things are hammers do

they need to be filed a tree shape do

they need to be replaced at some point

do the keys wiggle back and forth or the

key bushings worn and there's all of

this work worth it if there's too much

yes piano technicians rebuild and

refurbish pianos all the time a lot of

time it's worth it

to put new strings on a piano or new

hammers or new dampers felt or new key

bushings there are things that wear and

tear with lang and it totally makes

sense to replace those and it would be a

good idea to have an idea of the cost of

something like that so if you are

purchasing a second-hand piano well then

I also need to invest in the next two

years this type of work and how much is

that gonna cost and that could even be a

you know a bargaining you say

this piano I know I'm gonna have to

invest in some new in some sort of

refurbishing what about pills pedals

things that pianos should know about in

terms of what to do what not to do how

to identify what's wrong with a pedal

mm-hmm is it oftentimes the pedal itself

or something here that's a good question

the damper pedal the right pedal which

we use all the time it's a fairly simple

mechanism so if we have a problem with

pedals probably easy to fix and the same

with the left pedal of the does

different things on different pianos

there is fairly simple mechanism and

linkage that controls the UNA Corda

pedal or the soft pedal the middle pedal

again on different pianos does different

things on most quality grand pianos is

the sostenuto pedal I mean do you ever

use that pal I do

okay I do I use it a lot in things I

write kind of make it go out of my way

to write with it okay so the interesting

thing about that is the middle pedal or

the sostenuto pedal can be problematic

to work on and it's literally so if I

have a checklist know things that I'm

gonna do to a piano mm-hmm sostenuto

pedal very last thing how much does the

point where like that I mean some there

and because they're designed differently


different manufacturers and a lot of

manufacturers when it's set from the

factory it's gonna be fine okay there

are some other pianos where it's a

totally different design and depending

on the pianos mood that day it'll work

or it won't work


show you how it works just like that

just light it out these are all damper

levers so the back end of the key is

when we're playing it it just lifts the

damper lever and it lifts the damper off

the string and this is that big damper

tray so when we push the damper pedal

we're lifting every single damper at the

same time now it's a middle pedal

operates this and on the bottom here

there's like almost like a blade that

sort of rotates towards the dampers each

damper mechanism there is this tab which

is called the sostenuto tab and so if

none of the dampers or none of the keys

are being played and none of the dampers

are elevated the sostenuto rod

catching yeah it'll swing clear of the

sostenuto tabs play that note and I we

pushed down the sostenuto pedal yeah and

so yeah again all of the other notes you

will play

just like normal and that the dampers

won't catch yeah and it's hard to fix

because of the tabs themselves or the

rod the troubles with this are that some

pianos this sauce tenuto rod is on the

action so when you take the action out

the softer new rod isn't there and you

can't see how it interacts with the

damage I see so it's difficult to

identify the problem yes great yeah

while we're at it yeah I guess you know

treat treat them as not a piece of

furniture I guess but an instrument you

know to put your coffee cups on your

piano I may have done that to my piano

at home occasion but if something

happens to my piano I can fix it

Abby do treat them with respect and to

try your best to have them maintained

and do especially if you know you need

the piano to be as good as possible

develop a good relationship with someone

you trust a technician it may take a

while I don't like the idea of using

those services where you just you know

you go online or you call and they send

it's a big company they just send

someone your home because it's someone

different and you don't know them as

pianist do like technicians develop

relationships with the instruments and

they have their own little quirks

so yet you know have someone that you


tune your piano regularly take care of

your panels take care of your piano it's

just like you take care of yourself yeah

your family yeah thanks Damon

yeah thanks Ari this is amazing cool but

I have fun I like what we did here yes

well just let's go let's go have lunch

and leave it like this