Chapter 5: Regulating
Contents
1. 100 The Torque column in Table 5 allows you to compare fric tion values for different distances Conventional wooden parts shrink and swell and your readings will differ somewhat from season to season To reduce sideplay friction may need to be higher in parts with softer bushings and lower in parts with firmer bush ings Consult the manufacturer s specifications if avail able Steinway amp Sons for example recommends torque on the low end of the ranges in Table 5 242 Repeat the measurement in the opposite direction If the resistance is off by more than 50 mm grams check for debris and microscopic splinters between parts Just slid ing a piece of paper a few times between the parts may help If it doesn t remove the center pin and smooth the bird s eye a circular protrusion around the center pin hole on both sides of the part with a few light circular passes with 1000 grit or finer sandpaper If the wood is smooth the center pin itself may turn more smoothly in one direction than the other Install a new center pin one half size thicker as explained in Repinning Action Parts on page 244 Shank Center Pin Friction Affects Tone High friction in hammer shanks dulls the tone by increas ing the amount of time the hammer remains in contact with the strings Reducing shank friction aside from mak ing the action perform better can open up the tone appre ciably 241 http ww wessel Inickelandgross com m2. and soon the string is vibrating in all directions When the damper falls on the string it pushes the string down causing the vertical vibrations to quickly subside Vibrations around the hori zontal plane however cause the damper head to move left right You can observe this when loudly playing low bass notes the damper head flutters horizontally side to side when it touches the string By itself the damper can t stop horizontal vibrations that s the job of the damper bushing The bushing damps horizontal excursions of the string by limit ing side to side travel of the damper head The tighter the bushing the more effective it is However the adjustment of the damper wire can make the bushing even more effective Suppose that the string is deflected from its rest position by mm to the left and mm to the right Also suppose that the damper wire is mm thick and the opening in the bushing has a diameter of 3 mm leav ing mm of room on each side of the wire If the damper wire is in the middle of the bushing the string will move it equally in both directions for a total motion of 2 mm But if the wire leans against say the right side of the bushing the excursion to the right will cause almost no damper movement whereas the excursion to the left will bring the wire to only the middle of the hole The total motion will be only mm half of what it would be with the wire centered The degree of the lean must be very gentle
3. for example regulating the key dip let off blow distance and jack gap of a few guide notes may reveal dis crepancies in aftertouch between the bass and treble in just minutes If guide notes require excessive turning of regulating screws and buttons or you run out of range of adjustment check to ensure that the action rails have not moved the brackets are intact and fastened down firmly and the ac tion geometry is satisfactory see Chapter 9 Touch Ge ometry Playability on page 273 In a grand piano if ham mers block on strings or drop screws bind on the pin block suspect expanding action brackets page 149 Friction Since every part of the piano mechanism is affected by friction this is one of the most important and most over looked aspects of piano regulation The main sources of friction in the mechanism are e Metal and felt parts e g between center pins or key pins and their bushings e Metal and wood e g between key frame glides and key bed Wood and felt or leather e g between jacks and knuckles key end felts and damper underlevers Wood and wood e g between key frame and key bed Addressing friction between strings and their bearings is discussed in Lubricating String Bearings on page 113 238 The Grandwork Regulation Station is protected under U S patent no 8 227 674 2012 Sample page from Pianos Inside Out Copyright 2013 Mario Igrec Friction is
4. and aftertouch How Measure blow distance as depicted in Figure 345 To reduce shim the hammer rest rail or half blow rail with felt paper or cardboard shims In the case of a rest rail place the shims between its felt blocks and the action brackets Figure 346 Do not glue the shims in place yet To increase the blow distance remove the shims or cut the rail felt blocks this is unusual do this after step 5 In most studio uprights the blow distance should be 134 174 45 47 mm in spinets and consoles with compressed ac tions as little as 1 2 39 mm Ultimately adjust the blow distance and gap next step for optimal aftertouch step 5 4 Jack gap is the distance between the jack and the ham mer butt that ensures the jack s repositioning under the hammer butt after the key is released This distance should be as small as possible but sufficient for the jack to return consistently under the hammer butt In new actions the gap is less than 0 004 0 1 mm whereas it may need to be double that in worn ones The measurement how ever is unimportant you will adjust the gap by feel If the butts sit on the jacks no gap notes may bobble and miss You must regulate jack gap whenever you alter blow dis tance or key level How Depress each key lightly at the very top of its travel a few times and observe when the hammer begins to lift relative to the motion of the jack and wippen There should be a very small amo
5. and carpets and make sure you do not damage the piano case Never put your tools or parts on a finished surface without padding it with cloth felt or a mover s blanket Always put a sheet or mover s blanket under the keyboard or action on the floor the lubricants on the bottom of the key frame could transfer to the floor and get contaminated Remove all fragile objects from the Recommendations e Condition Parts must be in good condition or the regulation will not hold Clean and lubricate all contact points Do not realign worn action parts unless they rub against each other Light Use a dispersed strong source of light for general work shine a pointed light at an angle when shadows help you deter mine distances e g when regulating let off in the piano Use visual and tactile checks If you need to remove any parts e Mark the numbering and label the parts with masking tape for example before removing them e Take notes and photos that will help you realign the parts later Don t mix wood screws even when they appear to be the same small imperfections and burrs can wear out the wood piano and near it and be sure you have enough space to comfortably remove the keyboard and action Puta mover s blanket under the piano bench to protect the floor If you need to perform any repairs during the regula tion turn to Chapter 7 Repairs I suggest wearing thin cotton inspection gloves for most pi
6. or ridges temporarily affix a piece of tape to the flange if necessary Read the highest value dis played and compare it with the values in Table 5 Because you re measuring the force needed to over come the resistance to circular motion you really are measuring torque The advantage of expressing center pin friction as torque is that you can compare measurements taken at different distances from the center pin WNG for example measures flanges at 20 mm 2 while Steinway s 240 Gregory Graham provides instructions for building a jig that main tains the angle between the gauge and the part Search http my ptg org for Gram Gage Jig Instructions Friction 143 Table 5 Acceptable Friction Values for Center Pins P Distance from Friction Torque art 3 center pin g mm g Hammer shank flange 25 mm 1 5 4 0 37 100 Repetition lever Buckskin at drop 2 0 6 0 120 360 spring disengaged screw 58 mm Wippen flange 25 mm 1 5 4 0 37 100 Underlever flange 25 mm 1 0 4 0 25 100 Underlever top flange 25 mm 1 0 4 0 25 100 Sostenuto tab Tip 15 mm 1 0 6 0 15 90 spring disengaged Jack spring disengaged Tip of tender 0 5 4 0 12 100 25 mm Vertical damper lever ca 50 mm 1 0 8 0 50 400 specifications assume approximately 32 mm To calculate torque use the following formula 31 Torque Force x Distance At the radius of 25 mm for example a measurement of 4 grams indicates a torque of 100 mm grams 32 25x4
7. or the added friction will offset the benefits of this technique by making the damper less effective in the vertical plane The lean also makes damper movement when lifted with the pedal appear more precise because there is no fore aft movement of the damper heads own weight then lightly tap down the damper head or the underlever a few times You should feel resistance and see the tool tipping forward a little If the underlever knocks more than very softly against the tool lower it 10 Adjust pedal lift on guide dampers Sit at the piano and press the damper pedal slowly while observing the guide underlevers ignore the underlevers between them Adjust their capstans if so equipped or re move add shims under the tray felt under guide under 192 Regulating Figure 337 Wippen flange screws are usually in the back of the action Yamaha U3 Figure 338 The jack spring should be positioned in wip pen and jack notches and the jack base must be firmly attached to the wippen Jack spring notch Jack base Oxidation and wear will make that interface noisy and creaky First make sure that all springs are seated in their notches they often get dislocated when a pencil is re moved from the action To test the lubrication and wear of the springs and notches disconnect the bridle tape and lift the catcher very slowly If the motion is not smooth or you hear any noise remove the action and place it on a cradle then
8. the key depressed legato tenuto Typically backchecking is adjusted to between 12 and 12 to 15 mm from the strings The shorter this distance the less time the ham mer spends returning to the strings on restrike Without Regulating Sample page from Pianos Inside Out Copyright 2013 Mario Igrec Adjusting Damper Wires Viewing the damper wire from the front the segment under bend and the segment between bends 2 and 3 should be parallel to the plane on which the underlever moves up and down which should be vertical Bends and 2 abridge the misalignment between the under lever and the guide rail bushing These bends should be mirror images of each other and should allow the damper to move freely If they are angled too much the wire will rub against the left side of the bushing and the underlever will be pushed to the right Con versely if the bends are not angled sufficiently the wire will rub against the right side of the bushing and the underlever will be pushed to the left The wire should lightly rub against one side of the bushing consistently within each section see below a Side view b Front view Figure 327 Side and front views of a typical grand damper assembly Numbers indicate the bends in the wire page 402 Loosen the screw in the underlever top flange and set the underlever to rest on the tongue of the tool and the damper to sit on the strings then tighten the screw If the damper head
9. twists out of alignment with the strings loosen the screw twist the head slightly in the op posite direction and tighten the screw If that doesn t work lift and twist the damper wire under bend 2 with a pair of linesman or similar pliers while holding the under lever top flange with parallel pliers Lift the underlever and let the damper head return to the strings under its Bends 3 and 4 must be adjusted so the damper head is vertical and centered to the string s Viewed from the side the wire should be vertical except between bends and 2 and the felts at both ends of the damper head should sit on the strings with equal force Lifting and lowering the underlever should not change the alignment of the damper head Aside from observing the bends and the amount of side bearing that damper wires exert on guide rail bushings a good test is plac ing a small ruler on top of the damper heads If they are aligned cor rectly their tops will be parallel with the ruler To Center the Wire in the Bushing or Not If the damper wire bears against the bushing with significant force the bushing will wear out prematurely The logical conclusion is to adjust the wire to be centered perfectly in the bushing However the damper is actually more effective if the wire is slightly off center Here s why Let s look at a single bass string Although the hammer excites the string to vibrate in a vertical plane the vibrations change direc tion
10. Sample page from Pianos Inside Out Copyright 2013 Mario Igrec 135 Chapter 5 Regulating 6 6 We are Sancho Panzas to pianistic Don Quixotes 9 9 Benjamin McKlveen RPT In pianos the term regulation applies to adjusting the func tioning of the mechanism which consists of the action keyboard damper system and pedals The mechanism is regulated by repositioning aligning or shimming parts by turning their regulating screws or buttons and or by alter ing the thickness of various felts and leathers Every piano should be regulated periodically In mod erately used pianos the action should be regulated every few years and the keyboard as part of every other action regulation Regulate the pedals as part of every tuning The damper mechanism remains in regulation for a long time but should be regulated if the initial regulation was poor or when the damper system is rebuilt If the piano is used heavily or is exposed to adverse climate conditions check its regulation as part of each tuning Although this chapter is presented in sections that fo cus on one subsystem at a time keyboard action damp ers pedals I suggest reading the entire chapter first to get a sense of how these systems interact with each other For specifications and procedures specific to the piano you are regulating consult the manufacturer s service manual Protection When you work in a customer s home be careful with the furniture rugs
11. a huge factor in the performance of the ac tion keyboard and dampers Excessive friction causes premature wear and noises throughout the piano and negatively affects touchweight and the piano s overall playability Too little friction on the other hand makes the action feel bouncy and may cause the hammers to bobble double and triple repeat on hard blows see side bar Myth Truth Inconsistent friction makes the action feel uneven Evening it out is a prerequisite for adjusting touchweight and improving playability Friction affects not only the performance of action parts but also their wear Keeping friction within its nor mal range increases the life span of key pins bushings knuckles key end felts key frame glides and trapwork leathers Friction increases as parts wear out and felts and leathers harden The increase is especially pronounced between the jack and the knuckle which need to be lubri cated periodically Center pins tend to bind in their felt bushings due to the oxidation of the pins and the swelling of the felt especially in high humidity climates Lowering friction is discussed below If ends of center pins are green see Verdigris on page 246 Myth All action centers should have as little fric tion as possible without looseness Truth Until recently this view has been widely held even among physicists see for example W V McFerrin The Piano Its Acoustics p 153 but friction in fa
12. ano work The gloves not only protect your skin but also protect delicate parts in the action keyboard and damp ers from the oily acids and moisture on your skin Tip When the gloves get dirty and only if they are not contam inated with chemicals turn them inside out to double their use time Avoid touching uncoated metal parts such as strings and springs with bare hands 2 3 142 Regulating Christopher Brown RPT available from TPR Tools LLC ww tprtools com Not only does this device allow you to reproduce the curvature of the key bed it is also a com prehensive jig for regulating the action hanging hammers adjusting shank travel and more see Figure 263 Guide Notes Guide notes are the notes you measure and regulate first to get a quick idea of the regulation in different sections of the piano Usually the end notes in each section and a middle note in long sections these notes provide refer ences for observing and regulating the notes between them For example if you first set the blow distance ham mer height at rest on guide hammers in a grand action you can visually adjust the hammers to form a line be tween them Guide notes are also useful in rebuilding guide hammers hammers on guide notes for example act as templates for gluing the rest of the hammers Figure 994 on page 392 Guide notes allow you to quickly test multiple interre lated regulation steps in several areas of the keyboard In verticals
13. creaking or crackling noises when playing softly and when pressing the damper pedal slowly The noises indicate excessive friction which im pedes performance and accelerates wear Sluggishness Pull the bottom of the damper lever away from the damper spoon or pull the damper away from the strings and let it go If it doesn t snap back is the spring intact and engaged Severely oxidized Is it jam ming in the worn notch in the lever especially if the notch is covered with cloth Next push the top of the damper lever toward the rail and return it a few times If the mo tion feels rough or you hear a faint creaking noise the le ver spring notches Figure 341 need to be lubricated If in a hurry lubricate them with Protek Prolube For more per manent lubrication clean polish spring ends and clean lubricate the notches using the techniques de scribed in step 34 To test the friction of lever center pins pull the spring away from the damper lever with a hook 254 Thanks to Fred Sturm RPT for this technique Sample page from Pianos Inside Out Copyright 2013 Mario Igrec 3 Blow distance is the distance between the hammer at rest and the strings It determines the amount of force that the hammer can deliver to the strings the greater the dis tance the greater the force As hammers wear blow dis tance typically needs to be reduced Blow distance is di rectly proportional to key dip and inversely proportional to jack gap
14. ct acts as a shock absorber and provides the needed amount of mechanical damping that reduces the unwanted movement of action parts Without fric tion shanks and wippens would continue bouncing for a prolonged period of time during which repeti tion would be unpredictable and the hammer might hit the strings several times Center pin friction decreases during the heating season due to low humidity 2 9 This may be accompanied by clicking noises caused by loose center pins or key pins These are separate problems that should be addressed be fore the piano is regulated Assessing Friction To assess the overall friction quickly measure down weight and upweight on a few keys and calculate friction see Static Touchweight TW on page 276 If the fric tion is outside the ranges in the Touchweight Worksheet on page 277 you will need to reduce or increase it Both cases are discussed below If the piano is in a humid climate and has not been played for a long time playing it will tend to somewhat re duce friction Move the shanks and wippens through their range of motion a few times before measuring friction 239 In low humidity the bushing holes actually shrink somewhat and tighten around the bushing cloth as the wood shrinks the bushing holes become elliptical shrinking in diameter across the grain Sample page from Pianos Inside Out Copyright 2013 Mario Igrec Traditional center pins are made of German
15. disengage the butt springs Clean bare wooden notches with a sharpened dowel and lubricate them with a dry film lubricant If the notches are covered with cloth punchings rub them with powder lubricant If worn replace and lubricate them see Spring notch cloth punchings on page 413 Polish the spring hooks end that presses into the notch Hammer butt springs are not noisy in Schwander actions but make sure their spring cords are intact and that all springs are engaged 35 Damper lift rod Lift the end of the damper lift rod hold the action rack with the other hand and observe the lifting of dampers If the lifting is uneven or tapers to ward either end inspect and repair rod hooks and hinges as necessary see Uneven Damper Lift on page 253 Sample page from Pianos Inside Out Copyright 2013 Mario Igrec Noise Lift the rod slowly If its motion is not smooth and you hear noises lubricate the rod its hinges and damper lever felts If in a hurry turn the action at a right angle to the floor apply Protek Prolube and let it run down the rod Apply at a few points along the rod s length Press the tops of the levers to keep the damper lever felts away from the rod as the liquid flows 2 4 Apply Prolube to the rod hooks and hinge bushings You can also brush Prolube on damper spoons unless you have a different plan for them see step 36 If you remove the rod clean and polish it and its bracket bushings then app
16. e the keyboard and action on top of the padded front lid Depress the key slowly controlling its movement and look for the vertical distance between the hammer at let off and the position to which it drops just af ter let off This distance is the drop Ignore the hammer s rise as the key continues moving toward the bottom of the key travel The rise may be substantial if aftertouch is ex cessive but if the hammer doesn t drop at all reduce the blow distance to increase aftertouch see step 4 Adjust the drop by comparing it to the neighboring hammer as shown in Figure 316 It should be ca 6 1 5 mm below let off Regulating Grand Action 173 Tip When regulating the action with the keyboard on your lap the front rail of the key frame bends upward and the key dip decreases Keys may reach the bottom of their travel be fore the hammers reach the let off let alone drop To increase the key dip move your leg sideways away from the area you re working on 4 Aftertouch is the amount of key travel measured at the front of the key from the highest point in hammer travel let off to the bottom of the key travel with moderate pres sure It is a function of let off hammer blow distance and key dip and should be adjusted to around 0 040 1 0 mm Excessive aftertouch wastes energy makes repe tition sluggish and can cause the hammers to get jammed by the backchecks Insufficient aftertouch on the other ha
17. edia pdfs gram_gauge_usage pdf 242 Steinway amp Sons Worldwide Technical Reference Guide Grand Preparation p 21 Photo by Allen Wright RPT Sample page from Pianos Inside Out Copyright 2013 Mario Igrec Grand Action and Keyboard Evaluating and Preparing for Regulation 157 Figure 282 Brushing the knuckles with a soft suede brush Figure 283 Applying powder lubricant with a cosmetics brush Figure 284 Rubbing a powder lubricant onto the knuckles with the top stack tilted forward page 145 This is easiest to do with the top stack re moved and tipped forward 90 Figure 284 Cover the sur face under the knuckles with paper towels to catch excess lubricant Apply the lubricant with a small brush Figure 283 a pipe cleaner or by dabbing it on with your finger wearing cotton gloves Figure 284 Work it in with the fin ger or a felt block If you are in a hurry use a technique taught by Andr Oorebeek work the lubricant into a felt block support the hammers so the knuckles form a line and rub the knuckles with the block from one end to the other in each section Burnish the lubricant with a small spatula or a metal shank e g a screwdriver Carefully re move and dispose of the paper towels Combined with the lubrication of other friction points a powder lubricant will reduce the overall action friction to very low levels 6 to 8 g For an even greater reduction you could mask every thing b
18. empera ture This will improve the stability of let off regulation Rub a small amount of powder lubricant into each cloth and burnish with a metal shank 49 Lubricate jack tenders Lubricating let off buttons is usually sufficient lubrication for jack tenders but if they feel rough or were treated with a greasy lubricant clean them with alcohol and apply liquid dry film lubricant to them with a bottle brush 50 Vacuum excess powder lubricant 5 Reinstall the shank rest rail if you removed it earlier and if you don t intend to regulate the keyboard fasten the top stack onto the key frame Regulating Keyboard Grands and Verticals Functionally the keyboard is part of the action and should be regulated with it I treat the two as separate units be cause the keyboard tends to stay in regulation longer than the action top stack If you re pressed for time focusing on the action will generally yield greater improvement for the player than perfecting key level and key dip or adjusting key spacing For ultimate results however the keyboard action and damper system should be regulated together For example if the aftertouch is shallow after you regulate the let off and hammer blow distance you will have to de cide whether to reduce blow distance action or increase key dip keyboard You can t adjust the damper stop rail before you define key dip and even the damper lift timing depends on the hammer blow distance and k
19. ey dip Please note that for purposes of regulation I treat back checks as part of the action not the keyboard Since the regulation of the keyboard is mostly the same in grands and verticals it is described for both designs un der this heading Procedures that are unique to either de sign are explained as necessary The regulation of the keyboard involves the following procedures in this order e Bedding the key frame e Spacing the keys e De slanting the keys e Squaring the keys e Setting white key level e Setting black key level e Setting key dip white and black keys In vertical pianos the key frame is affixed to the key bed with screws and the regulating is quite straightfor ward In most grands though the key frame shifts side ways with the soft una corda pedal and bedding it to the key bed is critical Poor contact between the two causes knocking or rattling noises and the accumulation of dust Sample page from Pianos Inside Out Copyright 2013 Mario Igrec Figure 315 Regulating the drop Steinway Let off Drop A Backchecked Figure 316 Regulating the backchecking against the drop of the neighboring hammer sistance that the pianist has to overcome toward the bot tom of key travel as the tip of the repetition lever pushes against the drop screw How To adjust the drop pull out the action and work either with the keyboard halfway on your lap see Tip below or plac
20. eys It s normal to have to add some weight toward the bass and reduce weight toward the high treble p A Figure 317 Testing the consistency of let off by playing off the jack against the repetition lever the friction between the repetition lever and the knuckle and even the friction of the repetition lever s center pin If the variations in hammer height are large lubricate the first three friction points and make sure that the center pin friction is not too low see Friction on page 142 Increase spring tension slightly if necessary step 6 on page 175 This test checks not only the consistency of let off and drop but also of touchweight friction and hammer inertia It is even more effective at revealing inequalities in ppp response than playing off the jacks Too close to the strings Depress the damper pedal and pound each note twice in rapid succession clear the pedal between the notes If let off is too close to the strings the sound will be harsh and distorted either on both strikes or on the second strike In either case set the let off a little lower turn the button clockwise and repeat the test If you are not sure what the note should sound like set the let off practically at the string and compare the sound with the let off set to 3 mm the latter will sound cleaner Strings have greater excursion in the tenor and bass sections there you should test whether the hammer touches them at le
21. lerating motion with a well de fined bottom and with very little free play after the drop Measured at the front of the key this will be achieved within 0 030 to 0 060 0 8 to 1 5 mm after let off Adjusting Adjust the aftertouch by changing the key dip step 7 on page 164 or making small adjustments to blow distance step 1 on page 170 Maintain a reasonably straight and even hammer line Don t alter let off or drop to adjust the aftertouch Testing Test the let off drop and aftertouch as ex plained in the sidebar on page 174 Note When adjusting blow distance bounce the key a few times you may notice that the hammer stops at a slightly dif ferent height each time This is because hammer height at rest is affected by the tension of the repetition spring its friction 174 Regulating Sample page from Pianos Inside Out Copyright 2013 Mario Igrec Testing Let Off Drop and Aftertouch by Feel The following tests supplement visual checks and are optional They require good finger control and a refined sense of touch The room should be quiet but you will make a lot of noise let the owner know what you are doing Playing off the jacks Playing with control in ppp dynamics requires let off and drop to be close to the strings and to be extremely consistent The following tactile check known as playing off the jacks allows you to refine the results Perform the following tests with the damper pedal dep
22. ly liquid dry film lubricant to the rod and inside hard bracket bush ings if the bushings are of cloth swab them with a pow der lubricant instead Refresh the lever cloths by brush ing them with a firm pipe cleaner or a small brass bristle brush if you can reach without scratching the lift rod or spoons Lubricate the lever cloths where they touch the rod and damper spoons with powder lubricant applied with a folded pipe cleaner Figure 339 Burnish the lubri cant and vacuum the area Reinstall the rod and the brack ets if you removed them 36 Damper spoons when deteriorated increase action friction accelerate wear of damper lever felts and can be noisy Visually inspect the spoons If the plating is flaking or rust is visible replace them or they will quickly wear out the damper lever cloths If the cloths are contami nated with rust or caked up lubricant brush them with a small brass bristle brush without touching the spoons or with a firm folded pipe cleaner then rub burnish them with a powder lubricant or replace them Lift and prop the damper lift rod Clean and polish the spoons with pieces of felt or cloth then coat them with dry film lubri cant in liquid form with a felt wedge or pipe cleaner Fig ure 340 Make sure the lubricant doesn t get on the lever cloths A quick alternative is to apply Protek Prolube to the felts and spoons 37 Damper springs levers and lever notches can be responsible for oinking
23. nd causes inadvertent double repeating when you play softly the hammer and shank bounce between the string s and the jack because the jack does not escape sufficiently from under the knuckle Dependencies Since let off is tied to the position of the strings aftertouch is adjusted by altering key dip and or blow distance In a precisely regulated action those two distances should be consistent throughout but in reality they vary slightly from note to note and can be compromised to a certain degree Many technicians give priority to blow distance because it affects the hammer line horizontal alignment of hammers at rest and a straight hammer line makes the action look regulated Blow distance also affects the acceleration of the hammers and the amount of force they deliver to strings which is one more reason to keep the blow distance consistent Measuring Aftertouch is very sensitive to the curva ture of the key bed bench and should be adjusted inside the piano Although you can measure aftertouch by com paring the key height at let off and at the bottom of key travel I prefer adjusting it by feel This way you will auto matically compensate for variations in the size and curva ture of the knuckle and other discrepancies in action parts Press the key slowly to the point of let off and while observing the hammer press the key to the bottom of its travel The hammer should drop then rise a little and you should feel a short acce
24. p repo AU Figure 347 Adjusting the jack to hammer butt gap by turning key capstans
25. r motions Rub a powder lu bricant into the felt Figure 285 and burnish it with a metal shank Vacuum excess lubricant 4 Lubricate repetition spring repetition lever notch This applies to Steinway and similar designs Remove the top stack from the key frame and turn it upside down Dis lodge all repetition spring hooks and reaching between the wippens scrape the old caked lubricant from repeti tion lever notches with a thin pointed hardwood dowel Figure 273 on page 151 If there is a lot of lubricant in the notches or the lubricant is still greasy wipe the notches with cotton swabs dipped in a 90 alcohol Allow to dry 158 Regulating Figure 285 Applying and rubbing powder lubricant into wippen heel felts with a cotton glove Lubricate Spring Notches with Film or Grease Spring ends and repetition lever spring notches traditionally have been lubricated with mutton tallow Manufacturers chose this heavy grease to act as a brake to slow the motion of the repetition lever Combined with the friction of the repetition lever center pins the grease allowed stronger adjustment of the springs thus improving the reliability of repetition see Increas ing Friction on page 148 Unfortunately this lubricant quickly caked up and oxidized the springs rendering the action sluggish or unplayable We cringe today as we clean it from the springs and notches of almost every grand made in America before WW II Modern synthetic g
26. rease lubricants are much better they are stable and noncorrosive and promise great longevity However before you use one for this application consider that over time every grease lubricant loses effectiveness as it traps dust lint and wool fibers A dry film lubricant doesn t suffer from that problem Unless the friction of the repetition lever center pins is exceedingly low and hammers are particularly heavy the benefits of a grease lubricant may be outweighed by the long term effectiveness of a dry film lubricant then apply a dry film or grease lubricant to the notches with a folded pipe cleaner see sidebar Lubricate Spring Notches with Film or Grease Turn the top stack back up and clean old lubricant from the spring hooks with very fine steel wool 0000 dipped in alcohol or lacquer thinner then polish them with a rotary tool and a small buffing wheel use a chrome buffing compound or tripoli Wipe the buffing compound from the springs lubricate them with dry film lubricant and reposition them in the notches Squeeze each repetition lever If you feel in creased resistance at the start of the travel the springs have dented the notches if the dents are deep replace the wippens 48 Let off button cloth If the cloths on let off buttons are dimpled lightly brush the cloths with a brass bristle Sample page from Pianos Inside Out Copyright 2013 Mario Igrec brush sand them lightly then iron them at low t
27. ressed Depress a key until you feel increased resistance then depress it to the bottom of its travel with moderate force Figure 317 Reduce the force until the note barely sounds Repeat this test with the same amount of force on all white then black keys Each note should sound If a note doesn t its let off and drop are likely too low adjust and retest until the note sounds The more quietly you can play off the jacks the softer you will be able to play the piano with control If you feel markedly greater resistance on any of the notes those hammers may be blocking against the strings increase the let off and drop distances Slight discrepancies in resistance may be caused by the jack position at rest step 7 on page 176 Adjusting the jack slightly toward the player will reduce the resistance and vice versa Resistance also can be caused by wear and lack of lubrication on the knuckles lubrication of the repetition spring condition of let off but ton felts lubrication of the jack tender inconsistent force of the repe tition spring on the jack even a sluggish center pin Dropping the weight Assemble touchweight measurement weights to the total weight of approx 100 g Depress the pedal block the key with one hand and place the weights on a key with the other then let go of the key You should hear a faint sound Repeat on sev eral adjacent keys reducing the weight until notes start missing then add a few grams Test all k
28. silver and are not plated The plated center pins used in newer Asian pianos exhibit a reverse trend Moving the parts causes center pin friction to increase sometimes so much that the parts seize up The solution is to repin or rebush the parts page 244 Measuring Center Pin Friction Center pins contribute significantly to the overall friction in the action for an action to feel fast their friction should be toward the low end of the ranges listed in Table 5 Center pin friction also contributes to the even ness of action response and should be measured pre cisely when diagnosing friction issues and repinning or re bushing action parts Figure 264 Measuring center pin friction of a shank flange with a 10 gram tension gauge The photograph is taken from above The most precise way to measure center pin friction is with a 10 gram spring tension gauge for less formal meth ods see sidebar Other Ways to Test Center Pin Fric tion Hold the part e g a hammer shank or wippen so the center pin is vertical to eliminate the effects of gravity Push the part you are measuring e g the flange with the tip of the gram gauge probe at a spot that is as far from the center pin as indicated in Table 5 Hold the gauge lightly and follow the rotation of the part with it see Figure 264 To avoid a false high reading keep the probe pointed at the center pin Don t slide the probe and don t let it bind on grooves
29. t off Hold the damper pedal depressed and loudly play several quickly repeated octaves or big chords that include the note you are testing then quickly bring the hammer up but take it through let off very slowly If you feel string vibrations on the key or hear a zing indicat ing that the hammer is touching the string lower the let off a little turn the let off button clockwise and repeat until the hammer no longer touches the string Bump and aftertouch Hold the damper pedal depressed Press four adjacent white keys with the same hand and feel whether the bump in each key s travel starts at the same spot in the travel While holding the keys at the bump with the same force slide the fin ger of the other hand from one key top to another Figure 318 Slightly adjust the pressure of each finger and observe how the rela tionships between the keys change If the bump of one of the keys is higher either the let off and drop are lower the blow distance shorter or the action leverage higher than on other notes due to geometry inconsistencies That note is also likely to have greater aftertouch Correct the regulation and retest a Figure 318 Testing whether the start of the bump on adjacent keys is level 5 Backchecking height As explained in The Impor tance of Backchecking on page 77 backchecking speeds up repetition by preventing the hammer from getting too far from the strings after strikes that involve keeping
30. unt of free play in each key s movement during which the jack rises but the hammer does not move at all Adjust the gap by turning key cap stans Figure 347 or in a dropped action the screws or capstans on linkages that connect the keys to the wippens The gap should feel the same on all keys 5 Aftertouch is the distance that the front of the key trav els after the let off In most verticals it should be 0 040 0 060 1 0 1 5 mm Insufficient aftertouch causes ham mers to bobble as the hammer butts bounce off the jacks whereas excessive aftertouch causes inconsistent back checking wastes finger force and may cause the jacks to jam at the let off rail Aftertouch is directly proportional to key dip and inversely proportional to blow distance and jack gap How Depress each key and measure how far it travels after the let off occurs To measure aftertouch more pre cisely place a cardboard punching of the desired thick ness e g 0 040 1 0 mm on the front key punching and depress the key with moderate force place a weight of 8 to 10 oz ca 250 g on the front end of the key this will keep the measurements consistent from key to key Pressing the key just slightly more should take the ham mer through let off If the hammer is already past let off Regulating Vertical Action Pedals and Dampers 195 Figure 346 The hammer rail is supported by felt blocks Place shims under or above this felt if necessary E
31. ut the graphited areas of the repetition levers and spray them with a dry film lubricant Some pianists will then complain that the action doesn t provide enough feedback Caution Wash your hands thoroughly before playing the pi ano to avoid spreading the lubricant on the key tops If the keys get slippery wash them with alcohol If the owner or per former still complains protect the fallboard and the rest of the piano and mist them with a very small amount of hair spray don t spray directly 45 Sluggish or loose wippens Tilt the top stack for ward as depicted in Figure 284 so that the wippens hang loosely or barely sit on the wippen rail Move the wippens in groups toward the shanks and let go Repeat in the op posite direction If any wippens return slowly remove them and measure center pin torque on their flanges If the torque is high lubricate them page 148 Also mea sure the torque on jack and repetition lever center pins when one center is sluggish usually all of them are Next grasp each jack tender and gently move it left right a few times If you feel any looseness repin the jack and or the wippen flange Check the repetition lever pinning for looseness 46 Wippen heel felts Turn the top stack upside down and lightly brush wippen heel felts with a brass bristle brush If they are dented steam them lightly though not so much as to compromise the glue then iron them at low temperature with circula
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