LOOK AFTER YOUR PIANO HAMMERS
If you are considering buying a second hand piano, always check the HAMMERS
The piano hammers are oval shaped, and the part that strikes the strings to give it the "piano" sound.
The TOP of the hammer has special cream-coloured felt surrounding the inner wooden core; this part has coloured cored felt for the larger (bass/ tenor) hammers. It is then glued to a wooden shank, which (lower down) is glued to the hammer butt and various materials such as felt & leather glued to it. Grand piano hammers work on the same principle, and operate by means of a leather roller or leather knuckle near the flange. (See top of image above for rollers/ centre of image for hammer head).
At the base of the hammer, it swings backwards and forwards on a pinned flange - like a hinge. (c)
We are going to mainly look at the HAMMER HEAD >> the most important and expensive part of a piano mechanism.
The hammer felt is mainly responsible for the rich tone that the piano produces, along with the piano sounding in tune and also the condition of the strings. To change the tone of a piano (called 'voicing') requires expert work to readjust the fibres inside the hammer felt by using a needle tool along with re-facing/ skimming the heads. This also changes the 'touch' of the piano - combined with replenishing the fibres inside the front key washer baizes to give the keyboard more depth. The general sound and tone of a piano is predominantly down to the condition of the hammers, combined with the strings they strike. "Tinny" sounding pianos will be discussed later.
The hammer head is often overlooked when buying a piano, yet it is quite easy to spot if we look carefully.
Here is a diagram of an old piano mechanism, showing the hammer (b) under the damper.
The mechanism will need to reclined towards you to view the hammer head striking area >>
DIAGRAM 01
The piano hammers are oval shaped, and the part that strikes the strings to give it the "piano" sound.
The TOP of the hammer has special cream-coloured felt surrounding the inner wooden core; this part has coloured cored felt for the larger (bass/ tenor) hammers. It is then glued to a wooden shank, which (lower down) is glued to the hammer butt and various materials such as felt & leather glued to it. Grand piano hammers work on the same principle, and operate by means of a leather roller or leather knuckle near the flange. (See top of image above for rollers/ centre of image for hammer head).
At the base of the hammer, it swings backwards and forwards on a pinned flange - like a hinge. (c)
We are going to mainly look at the HAMMER HEAD >> the most important and expensive part of a piano mechanism.
The hammer felt is mainly responsible for the rich tone that the piano produces, along with the piano sounding in tune and also the condition of the strings. To change the tone of a piano (called 'voicing') requires expert work to readjust the fibres inside the hammer felt by using a needle tool along with re-facing/ skimming the heads. This also changes the 'touch' of the piano - combined with replenishing the fibres inside the front key washer baizes to give the keyboard more depth. The general sound and tone of a piano is predominantly down to the condition of the hammers, combined with the strings they strike. "Tinny" sounding pianos will be discussed later.
The hammer head is often overlooked when buying a piano, yet it is quite easy to spot if we look carefully.
Here is a diagram of an old piano mechanism, showing the hammer (b) under the damper.
The mechanism will need to reclined towards you to view the hammer head striking area >>
DIAGRAM 01
DIAGRAM 02
<<<<< Piano Hammer (modern under-damped mechanism)/ hammer OVER the damper
Always check the striking surface of the hammer felt for deep grooves (5).
(Look over the top of the hammer head to see the striking surface condition)
Over many years, piano hammers strike the strings millions of times.
The strings are like cheese wire and cut away at the hammer felt
Eventually deep grooves are cut into the hammer head felts
This part can be serviced many times over, but in extreme cases, if the head is worn or damaged,
they will need to replaced.
Other main components cannot be replaced, but the hammer head can.
During a piano tuning, if the hammers are in good condition, they can be lightly re-faced to reduce
excessive wear and tear.
DIAGRAM IMAGE 03
<<<<< Piano Hammer (modern under-damped mechanism)/ hammer OVER the damper
Always check the striking surface of the hammer felt for deep grooves (5).
(Look over the top of the hammer head to see the striking surface condition)
Over many years, piano hammers strike the strings millions of times.
The strings are like cheese wire and cut away at the hammer felt
Eventually deep grooves are cut into the hammer head felts
This part can be serviced many times over, but in extreme cases, if the head is worn or damaged,
they will need to replaced.
Other main components cannot be replaced, but the hammer head can.
During a piano tuning, if the hammers are in good condition, they can be lightly re-faced to reduce
excessive wear and tear.
DIAGRAM IMAGE 03
Image above showing the hammers - Bechstein upright piano. Unrestored/ good condition/ refaced every 12 months.
WHAT IS REFACING?
Hammer refacing (on the piano) is carried out annually when the felt has light grooves caused by the strings.
The felt is gently skimmed and sanded using garnet paper and a wooden board, to partially remove the grooves - a general wipe..
This also helps to preserve the soft touch and tone of the piano - all responsible of the hammer head.
The full refacing technique is only partly carried out here, as the hammers are installed and 'working'
REFACING 1 hammers is the first stage of the hammer preservation process, and it usually included in most upright piano tunings.
Grand piano re-facing 1 involves removing the mechanism & keyboard, and there may an additional charge, depending on the technician's policy.
If the piano is very old, deeply grooved hammers, flat "sawn off" or pear shaped looking hammers, (other components worn) then the refacing process may not work, and so the next stage should be considered - REFACING 2 - off the piano.
There are four categories when considering hammer preservation >>
1. REFACE (on the piano) 2. REFACE (off the piano) 3. RECOVER 4. RENEW
2 REFACE OFF THE PIANO
When the hammers are past normal wear and tear, or if you are considering a mechanism refurbishment, along with other processes, the hammers are removed from the action, and set up in the workshop for a fuller refacing job. This process applies to most upright and grand pianos, and costs in the region of £150 (without voicing).
When other components (leathers/ tapes/ felts) are removed, the hammers are clamped together in a vice for refacing.
The refacing process is more rigorous than 'on the piano' - and greater detailed work done for finishing and toning the hammers.
If the hammers are removed for other work (e.g. leathers) - then they all must be REFACED 2 as part of the work. Hammer grooves never line up with the strings a 2nd time, and if fitted without refacing, can cause serious damage to the hammer felts.
The following images show part of the fuller refacing process (some processes are omitted) >>
<1> Preparation for refacing hammers to remove grooves caused by the strings.
<2> Pre-voicing hammer felt using toning needles tool. (Final voicing is done on the piano/ hammers assembled).
<3> Restored hammers showing their original shape and profile, albeit - about 1mm smaller in diameter.
DIAGRAM IMAGES 04
WHAT IS REFACING?
Hammer refacing (on the piano) is carried out annually when the felt has light grooves caused by the strings.
The felt is gently skimmed and sanded using garnet paper and a wooden board, to partially remove the grooves - a general wipe..
This also helps to preserve the soft touch and tone of the piano - all responsible of the hammer head.
The full refacing technique is only partly carried out here, as the hammers are installed and 'working'
REFACING 1 hammers is the first stage of the hammer preservation process, and it usually included in most upright piano tunings.
Grand piano re-facing 1 involves removing the mechanism & keyboard, and there may an additional charge, depending on the technician's policy.
If the piano is very old, deeply grooved hammers, flat "sawn off" or pear shaped looking hammers, (other components worn) then the refacing process may not work, and so the next stage should be considered - REFACING 2 - off the piano.
There are four categories when considering hammer preservation >>
1. REFACE (on the piano) 2. REFACE (off the piano) 3. RECOVER 4. RENEW
2 REFACE OFF THE PIANO
When the hammers are past normal wear and tear, or if you are considering a mechanism refurbishment, along with other processes, the hammers are removed from the action, and set up in the workshop for a fuller refacing job. This process applies to most upright and grand pianos, and costs in the region of £150 (without voicing).
When other components (leathers/ tapes/ felts) are removed, the hammers are clamped together in a vice for refacing.
The refacing process is more rigorous than 'on the piano' - and greater detailed work done for finishing and toning the hammers.
If the hammers are removed for other work (e.g. leathers) - then they all must be REFACED 2 as part of the work. Hammer grooves never line up with the strings a 2nd time, and if fitted without refacing, can cause serious damage to the hammer felts.
The following images show part of the fuller refacing process (some processes are omitted) >>
<1> Preparation for refacing hammers to remove grooves caused by the strings.
<2> Pre-voicing hammer felt using toning needles tool. (Final voicing is done on the piano/ hammers assembled).
<3> Restored hammers showing their original shape and profile, albeit - about 1mm smaller in diameter.
DIAGRAM IMAGES 04
HAMMER HEAD WEAR & TEAR
It may be interesting to note - Image 1 (above left); the hammer head on our left seems to have slightly deeper grooves (caused by the 2 bass strings) than the rest of the hammers, as seen by the shadow. The 'middle' hammer has similar grooving to the left hammer, but the other hammer heads have less wear?
This is usually caused by the 'key of the music' we play our music in. The left hammer belongs to the note C (technically C28), one octave below Middle C. Certain hammers played in easier keys like C, G and F major get more wear than hammers played in F sharp major. Major and minor keys also have notes in common - so the grooves for each hammer will be at different depths.
When the hammer heads are refaced in bunches of five, all the heads are refaced to a point where the deepest grooves are removed, so the lighter grooved hammers may have lost their grooves prior to the worn hammers. This ensures that when the hammers are installed, they are all at the same profile and thickness to be regulated later. The hammers are then reset ready to play in any key - despite C major being the most popular.
A good piano technician can sometimes predict what keys the pianist plays in by the wear, tear and grooves caused by certain hammer heads. Generally speaking, an accomplished pianist will play in all keys, so the hammers will be likely to have even wear and tear throughout.
VOICING HAMMERS
There are several ways to 'voice' hammers. <1> Soft tone <2> Medium tone <3> Hard (percussive) tone
'Voicing' can also be used with the term 'toning' - the 2 words mean the same.
The better quality hammer usually produces a soft or medium tone - this is because a softer hammer felt is used, with a good quality core felt. Many German/ UK/ Korean pianos use this kind of hammer felt.
Yamaha pianos are well-known for their harder and percussive touch - producing a brighter tone; this is because the hammer felt is harder - not necessarily less in quality, just a different design of hammer.
High-valued pianos always use high quality/ expensive hammer heads
Budget pianos use average quality / less expensive hammer heads
Within reason, the tone may be adjusted and changed on any piano - but there are risks involved..... customer satisfaction being the main area. If the tone is wrong, you may be considered to upgrade to a better quality piano.
Remember: You cannot change radically the general characteristics and sound of a piano, only improve it.
SOFTEN THE TONE
The hammers are repeatedly 'injected' with four needles, deep into the felt - the surrounding edges of the hammer only, with very light injections to the face of the hammer. Along with re-facing, the needling tool is forced into each hammer up to around eight times. More needling is carried out to get a softer tone as requested.
HARDEN THE TONE
If the tone is too soft, the hammer felts may be 'doped' with a solution, or a hammer iron used to harden the sound.
Re-faced, recovered and renewed hammers must also go through this toning process.
If a set of hammers change their tone - from hard to soft, once they have reached the correct tone, it is difficult to go back to the original tone, should the new tone be unsuited.... so there are risks involved. If several attempts are made to constantly readjust the tone, this may RUIN the hammer felt, and beyond the skills of a technician to rectify it - there is no going back, and once a decision has been made, the customer will need to stick to it. These are the risks involved with hammer voicing.
THE TOUCH OF A PIANO
The touch of a piano is predominantly how much the hammer head has been serviced. Steps are also taken for 2nd hand pianos to invert all 88 front washer baizes (under the keys) that may have become compact with dust over many years of play. This improves the "depth of touch". All pianos must undergo full tuning and regulation for toning and touch to be successful.
The 'softness' of the touch is determined by a combination of good hammers, good voicing, good strings and good servicing.
Although it is generally unheard of to 'tone' and needle baize washers under a piano keyboard - however, we have tried this out and made various comparisons with new/ old/ dusty & compact washers - and there is a difference. For very old pianos, by simply turning these washers over helps to give the piano a better feel and touch. Plumped up cushions on your sofa will give your back a better 'cushion' rather than leaning back on an old scrunched up cushion.... think about it? Piano 'touch' works in the same way.
3. RECOVER
Depending on the condition of the hammer head felts, if they are badly worn/ deeply grooved more than 3mm/ sawn-off looking, insect damaged.... then they cannot be refaced. The next stage to consider is recovering.
This is a process whereby the whole of the hammer heads & shanks (stripped) are sent away to a hammer specialist.
New felt is T-riveted and glued on by machine, back onto the older existing wooden hammer core. The shank is used as a guide for the machine to align the hammer heads correctly. The shanks are not restored.
This is just like having a new tyre put back onto the existing wheel on your car.
These hammers were so badly insect damaged (moth invasion), they were beyond refacing, so had to be recovered.
The piano was dated around 1930, and the shanks/ glue joints were in good condition for the machine press.
DIAGRAM IMAGE 05
It may be interesting to note - Image 1 (above left); the hammer head on our left seems to have slightly deeper grooves (caused by the 2 bass strings) than the rest of the hammers, as seen by the shadow. The 'middle' hammer has similar grooving to the left hammer, but the other hammer heads have less wear?
This is usually caused by the 'key of the music' we play our music in. The left hammer belongs to the note C (technically C28), one octave below Middle C. Certain hammers played in easier keys like C, G and F major get more wear than hammers played in F sharp major. Major and minor keys also have notes in common - so the grooves for each hammer will be at different depths.
When the hammer heads are refaced in bunches of five, all the heads are refaced to a point where the deepest grooves are removed, so the lighter grooved hammers may have lost their grooves prior to the worn hammers. This ensures that when the hammers are installed, they are all at the same profile and thickness to be regulated later. The hammers are then reset ready to play in any key - despite C major being the most popular.
A good piano technician can sometimes predict what keys the pianist plays in by the wear, tear and grooves caused by certain hammer heads. Generally speaking, an accomplished pianist will play in all keys, so the hammers will be likely to have even wear and tear throughout.
VOICING HAMMERS
There are several ways to 'voice' hammers. <1> Soft tone <2> Medium tone <3> Hard (percussive) tone
'Voicing' can also be used with the term 'toning' - the 2 words mean the same.
The better quality hammer usually produces a soft or medium tone - this is because a softer hammer felt is used, with a good quality core felt. Many German/ UK/ Korean pianos use this kind of hammer felt.
Yamaha pianos are well-known for their harder and percussive touch - producing a brighter tone; this is because the hammer felt is harder - not necessarily less in quality, just a different design of hammer.
High-valued pianos always use high quality/ expensive hammer heads
Budget pianos use average quality / less expensive hammer heads
Within reason, the tone may be adjusted and changed on any piano - but there are risks involved..... customer satisfaction being the main area. If the tone is wrong, you may be considered to upgrade to a better quality piano.
Remember: You cannot change radically the general characteristics and sound of a piano, only improve it.
SOFTEN THE TONE
The hammers are repeatedly 'injected' with four needles, deep into the felt - the surrounding edges of the hammer only, with very light injections to the face of the hammer. Along with re-facing, the needling tool is forced into each hammer up to around eight times. More needling is carried out to get a softer tone as requested.
HARDEN THE TONE
If the tone is too soft, the hammer felts may be 'doped' with a solution, or a hammer iron used to harden the sound.
Re-faced, recovered and renewed hammers must also go through this toning process.
If a set of hammers change their tone - from hard to soft, once they have reached the correct tone, it is difficult to go back to the original tone, should the new tone be unsuited.... so there are risks involved. If several attempts are made to constantly readjust the tone, this may RUIN the hammer felt, and beyond the skills of a technician to rectify it - there is no going back, and once a decision has been made, the customer will need to stick to it. These are the risks involved with hammer voicing.
THE TOUCH OF A PIANO
The touch of a piano is predominantly how much the hammer head has been serviced. Steps are also taken for 2nd hand pianos to invert all 88 front washer baizes (under the keys) that may have become compact with dust over many years of play. This improves the "depth of touch". All pianos must undergo full tuning and regulation for toning and touch to be successful.
The 'softness' of the touch is determined by a combination of good hammers, good voicing, good strings and good servicing.
Although it is generally unheard of to 'tone' and needle baize washers under a piano keyboard - however, we have tried this out and made various comparisons with new/ old/ dusty & compact washers - and there is a difference. For very old pianos, by simply turning these washers over helps to give the piano a better feel and touch. Plumped up cushions on your sofa will give your back a better 'cushion' rather than leaning back on an old scrunched up cushion.... think about it? Piano 'touch' works in the same way.
3. RECOVER
Depending on the condition of the hammer head felts, if they are badly worn/ deeply grooved more than 3mm/ sawn-off looking, insect damaged.... then they cannot be refaced. The next stage to consider is recovering.
This is a process whereby the whole of the hammer heads & shanks (stripped) are sent away to a hammer specialist.
New felt is T-riveted and glued on by machine, back onto the older existing wooden hammer core. The shank is used as a guide for the machine to align the hammer heads correctly. The shanks are not restored.
This is just like having a new tyre put back onto the existing wheel on your car.
These hammers were so badly insect damaged (moth invasion), they were beyond refacing, so had to be recovered.
The piano was dated around 1930, and the shanks/ glue joints were in good condition for the machine press.
DIAGRAM IMAGE 05
ASSESSING THE RECOVERING PROCESS
During part of the recovering process (previously), the hammers are assessed to see if they can withstand the enormous pneumatic pressure of the machine. Remember that all wooden glue joints from the hammer head to shank must be in good condition for a recover to be successful. If the hammers are generally in poor condition, the specialists will overrule any request made by us, and may refuse the recovering process. This is for the following reasons: >>
# Weak and insecure glue joints between head & shank (any)
# Cracks appearing on the wood
# Several hammers, shanks or both missing from the order
# Odd hammer heads included in the order
# Brittle wood/ pianos older than 70 years of age
# Size and design of the hammer cores becoming obsolete
The following piano failed the recovering process (and any hopes of refacing aswell) >>
DIAGRAM IMAGE 06
During part of the recovering process (previously), the hammers are assessed to see if they can withstand the enormous pneumatic pressure of the machine. Remember that all wooden glue joints from the hammer head to shank must be in good condition for a recover to be successful. If the hammers are generally in poor condition, the specialists will overrule any request made by us, and may refuse the recovering process. This is for the following reasons: >>
# Weak and insecure glue joints between head & shank (any)
# Cracks appearing on the wood
# Several hammers, shanks or both missing from the order
# Odd hammer heads included in the order
# Brittle wood/ pianos older than 70 years of age
# Size and design of the hammer cores becoming obsolete
The following piano failed the recovering process (and any hopes of refacing aswell) >>
DIAGRAM IMAGE 06
(Above) Erard Grand Piano Mechanism - dated 1904.
# Hammers missing/ broken/ odd sets
# Hammer size & design obsolete
# Risk of insect damage spreading to Germany/ hammer specialist's workshop
.... the list continues!
The last resort is to renew the hammer heads (and several shanks).
4. RENEW
For full piano restorations, it is always advisable to renew the hammer heads and shanks in one go.
This will add greater value to the piano and offer better warranty.
The decision may be taken out of your hands, even if you agreed to a reface or recover earlier.
If the shanks are still in good condition (except Erard), they may be reused with new hammer heads.
The whole of the hammer heads are replaced onto new maple or mahogany wooden cores.
New T- rivets, glue, heads drilled & bored to correct angle. The inner coloured felt is preserved if possible
Images 1 + 2 showing the return of a set of new grand piano hammer heads and installation.
Image 3 showing anatomy of a grand piano hammer head
DIAGRAM IMAGES 07
# Hammers missing/ broken/ odd sets
# Hammer size & design obsolete
# Risk of insect damage spreading to Germany/ hammer specialist's workshop
.... the list continues!
The last resort is to renew the hammer heads (and several shanks).
4. RENEW
For full piano restorations, it is always advisable to renew the hammer heads and shanks in one go.
This will add greater value to the piano and offer better warranty.
The decision may be taken out of your hands, even if you agreed to a reface or recover earlier.
If the shanks are still in good condition (except Erard), they may be reused with new hammer heads.
The whole of the hammer heads are replaced onto new maple or mahogany wooden cores.
New T- rivets, glue, heads drilled & bored to correct angle. The inner coloured felt is preserved if possible
Images 1 + 2 showing the return of a set of new grand piano hammer heads and installation.
Image 3 showing anatomy of a grand piano hammer head
DIAGRAM IMAGES 07
The hammers have been pre-voiced in the workshop - re-facing is obviously unnecessary as the hammers are new.
Even though we requested a "medium tone" hammer head, they all must undergo full voicing and toning.
RE-VOICING MY PIANO (Scenario)
Mrs Smith has just bought a second hand upright piano - Yamaha U3..... dated 1995.
The piano plays well, nicely in tune, but the sound is generally brighter/ tinny than her sister's piano - Yamaha U1..
What can be done?
Well, first of all, it is impossible for any piano technician to replicate the identical sound of the U3 with the U1. Also, we will never know the exact requirements of Mrs Smith, and how she wants the voicing/touch to become.... this is purely down to the customer. Remember that you can never change the general characteristics of a piano.... even after major voicing work. There will be improvements, but the margins may only be minimal. The general voicing/ touch of a piano is always down to personal taste.
We can always "go through the motions" and help to improve the tone/ touch, but we will never know exactly what the customer wants in terms of touch/ tone/ voicing.... unless they try out and buy a different piano.
Piano hammers also vary greatly, even if we had two U3s standing next to each other. Nor can we use the U1 as a template.
This is the fixed procedure & costs we consider for re-voicing hammers on a good 2nd hand piano.
<1> Move the whole piano to our workshop. (Yes, this may involve a second removal)
<2> Assess the hammers for their condition/ mild - medium grooving is expected.
<3> Remove all 88 hammers from the action/ number & stack.
<4> Replace hammer butt leathers/ bridle tapes if needed (check butt springs & loops and advise)
(We also replace the hammer rest baize if needed, due to refaced hammers).
<5> Re-face hammer head felts to remove the grooves/ profile hammers - workshop.
<6> Pre-voice/ needling of hammers with toning needles in workshop (this is guess work at this stage)
<7> Assemble/ realign/ spacing of hammers/ travel (camber) shims added to flanges.
<8> Complete action regulation/ keys, hammers, undercarriages and dampers.
<9> Test ring-on with strings/ mute string with hammer head to determine 'flat spots' on hammers.Adjust.
<10> Full voicing and toning of hammers in the piano/ invert and plush-up front rail washers.
<11> Tune piano to C523.3Hz/ further tests.
<12> Return piano to customer.
Cost = £500 - £600 estimated (ex. carriage fees/ upright piano only)
Grand piano = £700 - £900 (ex. carriage/ storage fees)
Even though we requested a "medium tone" hammer head, they all must undergo full voicing and toning.
RE-VOICING MY PIANO (Scenario)
Mrs Smith has just bought a second hand upright piano - Yamaha U3..... dated 1995.
The piano plays well, nicely in tune, but the sound is generally brighter/ tinny than her sister's piano - Yamaha U1..
What can be done?
Well, first of all, it is impossible for any piano technician to replicate the identical sound of the U3 with the U1. Also, we will never know the exact requirements of Mrs Smith, and how she wants the voicing/touch to become.... this is purely down to the customer. Remember that you can never change the general characteristics of a piano.... even after major voicing work. There will be improvements, but the margins may only be minimal. The general voicing/ touch of a piano is always down to personal taste.
We can always "go through the motions" and help to improve the tone/ touch, but we will never know exactly what the customer wants in terms of touch/ tone/ voicing.... unless they try out and buy a different piano.
Piano hammers also vary greatly, even if we had two U3s standing next to each other. Nor can we use the U1 as a template.
This is the fixed procedure & costs we consider for re-voicing hammers on a good 2nd hand piano.
<1> Move the whole piano to our workshop. (Yes, this may involve a second removal)
<2> Assess the hammers for their condition/ mild - medium grooving is expected.
<3> Remove all 88 hammers from the action/ number & stack.
<4> Replace hammer butt leathers/ bridle tapes if needed (check butt springs & loops and advise)
(We also replace the hammer rest baize if needed, due to refaced hammers).
<5> Re-face hammer head felts to remove the grooves/ profile hammers - workshop.
<6> Pre-voice/ needling of hammers with toning needles in workshop (this is guess work at this stage)
<7> Assemble/ realign/ spacing of hammers/ travel (camber) shims added to flanges.
<8> Complete action regulation/ keys, hammers, undercarriages and dampers.
<9> Test ring-on with strings/ mute string with hammer head to determine 'flat spots' on hammers.Adjust.
<10> Full voicing and toning of hammers in the piano/ invert and plush-up front rail washers.
<11> Tune piano to C523.3Hz/ further tests.
<12> Return piano to customer.
Cost = £500 - £600 estimated (ex. carriage fees/ upright piano only)
Grand piano = £700 - £900 (ex. carriage/ storage fees)
REGULATING HAMMERS TO THE PIANO MECHANISM (after reface 2) / X+Y RATIO
If the hammers have been seriously refaced (2) - caused by deep grooves / uneven and flat hammers, and should the re-facing process be successful, depending on the depth of the grooves removed (on average, say 2-3mm), the hammer head in effect is now smaller in size and profile than it used to be by 2-3 mm. Although this reface 2 option is the quickest and cheapest to do in the workshop (no waiting of 6 weeks for new hammers, no additional gluing & hanging hammers etc.).... unfortunately this is just the start of a long regulation process ahead, when the hammers are installed onto the action rail. If the hammers have been recovered or renewed, there is still a lot of adjustments to make later, but by far not as much as reface 2.
For a piano mechanism to work correctly and to be perfectly synchronised with all other components such as the undercarriage lever, jack, damper, set-off buttons etc., the hammer head must be at the correct distance from the string at rest.... this is critical. The first two set-up regulation procedures is to check the hammer distance [X] simultaneously with the key dip [Y] - the distance it takes for the key to be pressed down. The ratio must be 5:1 (or 1:5) - whichever way you look at it, and most piano mechanisms in the world (upright & grand) are set up using this ratio before any other adjustments are made. If not 5:1, the action will not work correctly. The number 5 = X (hammer). The number 1 = Y (key).
Why not quiz your local piano tuner, and ask them.... "what are the two most critical components to be adjusted first on a piano mechanism?" .... and if they know their stuff, they should reply "hammer and key" (of course).
i.e. when the key is pressed down, the hammer moves five times its distance.
The following diagram demonstrates this (see red arrows) >>
DIAGRAM 08
If the hammers have been seriously refaced (2) - caused by deep grooves / uneven and flat hammers, and should the re-facing process be successful, depending on the depth of the grooves removed (on average, say 2-3mm), the hammer head in effect is now smaller in size and profile than it used to be by 2-3 mm. Although this reface 2 option is the quickest and cheapest to do in the workshop (no waiting of 6 weeks for new hammers, no additional gluing & hanging hammers etc.).... unfortunately this is just the start of a long regulation process ahead, when the hammers are installed onto the action rail. If the hammers have been recovered or renewed, there is still a lot of adjustments to make later, but by far not as much as reface 2.
For a piano mechanism to work correctly and to be perfectly synchronised with all other components such as the undercarriage lever, jack, damper, set-off buttons etc., the hammer head must be at the correct distance from the string at rest.... this is critical. The first two set-up regulation procedures is to check the hammer distance [X] simultaneously with the key dip [Y] - the distance it takes for the key to be pressed down. The ratio must be 5:1 (or 1:5) - whichever way you look at it, and most piano mechanisms in the world (upright & grand) are set up using this ratio before any other adjustments are made. If not 5:1, the action will not work correctly. The number 5 = X (hammer). The number 1 = Y (key).
Why not quiz your local piano tuner, and ask them.... "what are the two most critical components to be adjusted first on a piano mechanism?" .... and if they know their stuff, they should reply "hammer and key" (of course).
i.e. when the key is pressed down, the hammer moves five times its distance.
The following diagram demonstrates this (see red arrows) >>
DIAGRAM 08
After re-facing 2, should the hammers have lost 3mm of felt (which would have been 3mm in any case caused by the grooves), this will increase the hammer distance to the string by 3mm. The average distance for X on most pianos is 47mm. This is measured either wilth a hammer block tool, or Vernier calipers. If Y (keyboard/ key frame/ key tops) has not been restored, this is likely to be a little deeper than the optimum 9.5mm - perhaps 10mm due to wear.... this key dip distance is often acceptable and liked by piano technicians and pianists (most grand pianos have a key dip of 10mm). Key dip is measured with a key dip tool.
Should the hammer not rebound correctly (often it may 'bubble' backwards & forwards several times) - then the distance which is presently 50mm must be reduced back to 47mm to allow the back check to "catch" the hammer on the rebound. The most common task to build up the hammer rest rail baize is with thin strips of felt (glued between the wooden rest rail (e) [wavy lines], and the hammer rest rail baize [criss-cross pattern]. Should the key dip need any final adjustments, paper or card washers are added or subtracted underneath the round baize front washers (about 6mm in thickness) - to the left of double arrow Y.
These measurements often vary if the hammer rest rail is warped through age - it may be bowed in or out, so parts could be spot-on - 47mm, some 45mm (bowed inwards) or even over 50mm (bowed outwards). Certain piano mechanism rest rails allow you to add or subtract felt pads under each of the rest rail fulcrum points (e.g. Otto Higel actions), or sometimes washers may be added to the rest rail mounting screws to increase the distance.... however, this can be quite a long process. When X + Y are set up correctly "across the board", and all 85 or 88 notes are checked individually, this will have thrown out all previous regulation adjustments made to the piano mechanism inners. so all key capstan dowel screws / rocker grub screws (assuming not seized), back checks, set-off screws (assuming not seized) and a combination of about 20 adjustments PER NOTE must be made (regulation) by either bending wires, turning screws, adding or subtracting paper/ card shims and adjusting lift wires (lift wires mainly refer to over-damped pianos.... if not seized!) .... the list goes on.
Piano regulation is not covered here, however should you be interested in the process, please ask your local tuners (or me!)
Piano hammer care, regulation, repairs, renovation is one of our top priorities since the hammer head itself is one the most expensive components inside a piano mechanism. If the hammers are preserved and maintained regularly (servicing your piano), your piano will last for many decades to come. Many old pianos (with an average name) just become an item of furniture, or possibly end up on the scrap heap because replacing the hammers costs more than replacing your kitchen.
"TINNY" SOUNDING PIANOS
A piano with a tinny/ harsh sound to it usually means the hammers are past their best and need replacing. Some improvements may be done if possible, depending on the age, condition of the piano, and how frequently serviced (not tuned - this is separate).
Tinny pianos are caused by a few things:-
1. Hammers badly grooved & dented by the strings
2. Rusty/ corroded / old piano strings (especially the longer treble strings, just below Middle C area).
3. 'Dusty' hammer felts, caused by excessive damp/ moisture/ cold room, then room warmed up.
Hammer felts become moist, then dry out (repeated several times by on/off heating) = tinny sounding piano.
4. Various odd strings drifted out of tune (unisons)
If the piano is predominantly kept in a damp/ cold environment, only small improvements may be done.
Reducing tinny sounding hammers is not included with a piano tuning fee, but if item 4 applies only, this may be cured.
Re-toning the hammers will require a full piano tuning, then followed by service work done to the hammers.
Remember that if item 2 applies above, no matter how much is done to the hammers, this will never improve the tone if the strings are very old and rusty/ corroded. For a successful re-tone, the piano must undergo full restoration, and have new strings fitted combined with either a reface 2/ recover 3 or renew 4. Re-stringing a piano is quite expensive.
CHURCH PIANOS
Within the piano tuning trade, should a piano be kept in a cold/ damp/ moist environment such as a large room, garage, out-house, village hall, church, chapel, cathedral etc.... are given the nick-name "church piano". Regrettably, many acoustic pianos kept like this where there are sudden changes in temperature and humidity have little hope of re-toning to a good standard. This usually means that the hammer felt has deteriorated so much, to the point of no return. In cases like these, a reface 2 would be the minimum requirements. A standard piano tuning visit does not include re-toning, and so to improve this, the piano must first be tuned - then toned afterwards. By constant fluctuations of temperature and humidity (heating only on when a service is in progress, e.g Sunday service/ wedding), the hammer felts become damp, then dry out, then damp, then dry out over and over again, each time deteriorating the felt to a point where the hammer felt becomes a block of compact dust. Nothing can improve this, and the hammers will need to re covered or replaced.
"Church" piano hammers with this fault are often highlighted as the felt becomes brittle/ dusty/ badly stained, dark yellow and/or having mould deposits on the crown of the hammers - caused by damp. A piano kept in good condition (average family piano) will show that the hammer felts have mild discolouration, light cream/ ivory appearance to the hammer felts.
Old or neglected pianos might improve the tone after a reface 1 - depending on condition. In some cases, a full re-tone or recover might not be economical, and cost more than the value of the piano.
OVER-DAMPED UPRIGHT PIANOS (with overhead damper rail/ bird cage action) - see Diagram 01 or 08 for reference.
For any toning of hammers (reface 1) - the overhead damper rail & lift wires must be removed first, then relocated after the work.
This is subject to an additional charge, depending on design and level of difficulty to remove/ replace.
GRAND PIANOS
For any toning of hammers (reface 1) - the mechanism & keyboard must be removed first, subject to an additional charge.
MINI EAVESTAFF UPRIGHT PIANOS (1930s design)
For any toning of hammers (reface 1) - depending on condition, the whole piano may need to be shipped to the workshop.
On-site toning/ major repairs are seldom done to these pianos.
<< HOME
Should the hammer not rebound correctly (often it may 'bubble' backwards & forwards several times) - then the distance which is presently 50mm must be reduced back to 47mm to allow the back check to "catch" the hammer on the rebound. The most common task to build up the hammer rest rail baize is with thin strips of felt (glued between the wooden rest rail (e) [wavy lines], and the hammer rest rail baize [criss-cross pattern]. Should the key dip need any final adjustments, paper or card washers are added or subtracted underneath the round baize front washers (about 6mm in thickness) - to the left of double arrow Y.
These measurements often vary if the hammer rest rail is warped through age - it may be bowed in or out, so parts could be spot-on - 47mm, some 45mm (bowed inwards) or even over 50mm (bowed outwards). Certain piano mechanism rest rails allow you to add or subtract felt pads under each of the rest rail fulcrum points (e.g. Otto Higel actions), or sometimes washers may be added to the rest rail mounting screws to increase the distance.... however, this can be quite a long process. When X + Y are set up correctly "across the board", and all 85 or 88 notes are checked individually, this will have thrown out all previous regulation adjustments made to the piano mechanism inners. so all key capstan dowel screws / rocker grub screws (assuming not seized), back checks, set-off screws (assuming not seized) and a combination of about 20 adjustments PER NOTE must be made (regulation) by either bending wires, turning screws, adding or subtracting paper/ card shims and adjusting lift wires (lift wires mainly refer to over-damped pianos.... if not seized!) .... the list goes on.
Piano regulation is not covered here, however should you be interested in the process, please ask your local tuners (or me!)
Piano hammer care, regulation, repairs, renovation is one of our top priorities since the hammer head itself is one the most expensive components inside a piano mechanism. If the hammers are preserved and maintained regularly (servicing your piano), your piano will last for many decades to come. Many old pianos (with an average name) just become an item of furniture, or possibly end up on the scrap heap because replacing the hammers costs more than replacing your kitchen.
"TINNY" SOUNDING PIANOS
A piano with a tinny/ harsh sound to it usually means the hammers are past their best and need replacing. Some improvements may be done if possible, depending on the age, condition of the piano, and how frequently serviced (not tuned - this is separate).
Tinny pianos are caused by a few things:-
1. Hammers badly grooved & dented by the strings
2. Rusty/ corroded / old piano strings (especially the longer treble strings, just below Middle C area).
3. 'Dusty' hammer felts, caused by excessive damp/ moisture/ cold room, then room warmed up.
Hammer felts become moist, then dry out (repeated several times by on/off heating) = tinny sounding piano.
4. Various odd strings drifted out of tune (unisons)
If the piano is predominantly kept in a damp/ cold environment, only small improvements may be done.
Reducing tinny sounding hammers is not included with a piano tuning fee, but if item 4 applies only, this may be cured.
Re-toning the hammers will require a full piano tuning, then followed by service work done to the hammers.
Remember that if item 2 applies above, no matter how much is done to the hammers, this will never improve the tone if the strings are very old and rusty/ corroded. For a successful re-tone, the piano must undergo full restoration, and have new strings fitted combined with either a reface 2/ recover 3 or renew 4. Re-stringing a piano is quite expensive.
CHURCH PIANOS
Within the piano tuning trade, should a piano be kept in a cold/ damp/ moist environment such as a large room, garage, out-house, village hall, church, chapel, cathedral etc.... are given the nick-name "church piano". Regrettably, many acoustic pianos kept like this where there are sudden changes in temperature and humidity have little hope of re-toning to a good standard. This usually means that the hammer felt has deteriorated so much, to the point of no return. In cases like these, a reface 2 would be the minimum requirements. A standard piano tuning visit does not include re-toning, and so to improve this, the piano must first be tuned - then toned afterwards. By constant fluctuations of temperature and humidity (heating only on when a service is in progress, e.g Sunday service/ wedding), the hammer felts become damp, then dry out, then damp, then dry out over and over again, each time deteriorating the felt to a point where the hammer felt becomes a block of compact dust. Nothing can improve this, and the hammers will need to re covered or replaced.
"Church" piano hammers with this fault are often highlighted as the felt becomes brittle/ dusty/ badly stained, dark yellow and/or having mould deposits on the crown of the hammers - caused by damp. A piano kept in good condition (average family piano) will show that the hammer felts have mild discolouration, light cream/ ivory appearance to the hammer felts.
Old or neglected pianos might improve the tone after a reface 1 - depending on condition. In some cases, a full re-tone or recover might not be economical, and cost more than the value of the piano.
OVER-DAMPED UPRIGHT PIANOS (with overhead damper rail/ bird cage action) - see Diagram 01 or 08 for reference.
For any toning of hammers (reface 1) - the overhead damper rail & lift wires must be removed first, then relocated after the work.
This is subject to an additional charge, depending on design and level of difficulty to remove/ replace.
GRAND PIANOS
For any toning of hammers (reface 1) - the mechanism & keyboard must be removed first, subject to an additional charge.
MINI EAVESTAFF UPRIGHT PIANOS (1930s design)
For any toning of hammers (reface 1) - depending on condition, the whole piano may need to be shipped to the workshop.
On-site toning/ major repairs are seldom done to these pianos.
<< HOME
