GRAND REGULATION - part I

In the last post, we discussed a 50-point checklist to be used in regulating grands. Last month we printed a grand regulation chart which shows how each of the nine regulation steps directly affect the others. Now in combining these two concepts, we will go through each of the 50 points in the checklist and explain in detail to how perform each step.

I. KEYS & KEYFRAME

1) TIGHTEN ALL SCREWS, REMOVE ACTION AND KEYS

Before anything else is done to piano, all of the screws should be tightened. This includes the screws, case parts, action parts, lyre and damper assembly parts. This is to insure that everything that should be snug and tight is, eliminating any noises or excess wear which could crop up from loose fittings. It also insures all of the moving parts are in correct relationship to each other. When tightening down the plate use a large screwdriver has had the tip ground to fit the plate screw heads. The whole blade should fit the screw head, not just the corners of the blade. I use a Sears 3/8” Craftsman which has a square shank, enabling me use a crescent wrench on the shank to help turn the screw. If this method is used, be sure to put your weight on the screwdriver to keep from ruining the head of the screw. Do not turn plate screws more than ½ turn at a time, and skip every other screw. Otherwise, it is very easy to flex the plate running the risk of possible plate breakage. Do not attempt to change the nose bolts unless something is obviously wrong, such as the bolt coming loose in the beams under the soundboard. Nose bolts are not to be tightened to achieve more downbearing. Tighten all action and case part screws hand tight. Overtightening will only crush the wood or else result in a stripped screw hole. On aluminium action rails, if the hole is stripped, a larger, self-tapping screw will solve the problem. Do use common sense and refrain from tightening screws which are adjustments to action mechanisms. These include the drop, let-off, jack regulating screw, jack stop rail, repetition lever and spring screws, cheekblock adjusting screws, etc. 

To tighten the action screws, the action must be removed from inside the piano. Take care not to depress any of the keys when pulling the action out, or a broken hammer shank will result. Place a hand on each end of the keyframe and pull the action out slowly. Now remove the action bracket screws which hold the stack into the keyframe. Some actions have the front screws (nearest the keyboard) slanted at an angle. These are removed first and installed last. Make sure you have some method for returning the action screws back into their original holes. Set the stack aside and remove all 88 keys. To keep from enlarging the balance pin hole on the bottom of the key, take hold of the key at the back as well as the front and lift off evenly.

2) SAND KEYBED, APPLY TALC OR SLIPSPRAY

The ideal match between the keybed and the keyframe is for both to be perfectly straight and level. Otherwise, when the keyframe shifts, high and low spots are sure to occur, resulting in noises. Therefore, sand lightly the keybed to give it a level, smooth surface upon which the keyframe can slide. Also, apply talc, slipspray, or some other substance to help the keyframe shift quickly back and forth. A straightedge may be helpful in finding high/low places.

3) SEAT ACTION ON KEYFRAME, REPAIR STRIPPED SCREW HOLES

Seating an action frame is an often overlooked procedure. The keyframe should be straight and flat on its underside to match the keybed. If the action brackets have any amount of space between the bottom of the bracket and the top of the screw hole on the keyframe, a warped keyframe will result when the brackets are screwed down tight. Of course, if any holes are stripped, drill-plug and redrill. Cross-threading the screw holes can be eliminated by starting the screws by hand or by turning the screws backward until it drops into the threads.

4) BED KEYFRAME: BACKRAIL, FRONTRAIL, STUDS; SAND AS NECESSARY

 Now that the stack is on the keyframe without the keys, back up the balance rail bedding screws (make sure you get the ones only visible from underneath on Yamahas) and install the action into the keybed, securing the cheekblocks. The cheekblocks should apply a small amount of pressure to the keyframe to keep it down, but not so much as to cause it to raise in the middle. A perfect fit is when the shift pedal works freely with the keyframe secured on the key keybed. Bed the backrail first, then the front rail, lastly the balancerail studs. The correct specification here is to not have any spaces between any of the three rails at their point of contact with the keybed, both in the regular and in the shift positions. When bedding the front or backrail, tap on the rail and listen for knocking noises. Mark offending areas with chalk. If the knock is at the ends of the front rail, the cheekblocks were not fitted correctly. If the knocks are at the middle of the front rail, try to loosen the cheekblocks to see if they were too tight. If not, then lift the front or backrail up enough to places and paper strips grit side up under the contact points on each side of the chalk marks. Draw the sandpaper out and recheck the area for knocks. Remember that the area to be sanded is not where the chalk marks are, as these are the high places, but rather the low places surrounding the chalk marks. Go slow in the sanding process so as not to sand the keyframe too much, producing more high places. On a badly warped keyframe, one might have to cut out strips on the top of the frame and hammer in hardwood wedges in order to straighten it out (front or back rail only). 

Bedding the balance rail can be done by either of two methods. The short method is to take a straightedge over the entire length of the keyframe, spanning the front and back rails over where a stud exists. Turn the stud down until it just touches the straightedge. At this point, the three rails are in a straight line. Do this to every stud, and if the keybed is perfectly flat (which it isn’t) then the keyframe should fit. But since the keybed is not perfect, correct any small differences by installing the keyframe complete with keys and stack into the piano, securing the cheekblocks. Now by lifting gently on the top of the stud, and at the same time knocking lightly with the other hand, adjust the stud so that it makes a knocking noise when the stud is lifted, but is secure with no pressure on the stud. Do this to all of the studs and the keyframe can be considered bedded to the keybed. The other method is with using strips of newspaper. With the keys off the keyframe but with the stack screwed on and cheekblocks secured, slide a strip of newspaper under each of the bedding screws and starting at one end, turn the studs down until friction is felt when the newspaper is pulled gently. Go onto the next stud and turn it down also until resistance is felt. Recheck the first and second studs before going on to the third. Continue the operation remembering to recheck those studs already set until all of the studs are down. Check the front rail to make sure that the studs are not down so far as to raise the front rail and you are finished.

5) ALIGN ACTION RAIL DISTANCE IF NEEDED

All piano actions were designed with a specific distance between the middle of the centre pin of the hammer shank to the middle of the center pin on the whippen flange. Most actions have an adjustment on one of the other rail to correct this measurement. Some, like Steinway, are permanently set. However, if this distance is not correct, the action will not play right and is impossible to fine regulate. Contact the manufacturer for the correct specifications for the particular instrument if this appears to be the case.

6) REMOVE THE STACK, POLISH KEY PINS, CLEAN KEYFRAME

Take the stack back off the keyframe and set it aside. If the punchings and backrail cloth are in good shape, clean with a brush. If not, replace with new felt and cardboard. Clean the key pins or replace if they are pitted. Turn the front rail pins back straight if they were turned before.

7) PUT KEYS BACK ON KEYFRAME, CHECK CENTER HOLE FOR LOOSE/TIGHT FIT

Return the keys back on the keyframe in the same manner in which they were removed, taking care not to damage the balance hole. If the keys do not slip easily over the pins, ease the balance hole either by removing excess wood (from the sides only) with a file or else by squeezing the wood with a balance pin hole easing tool (available from Yamaha). The file used to remove wood is a #6 round tail bastard with two edges ground down so that only the sides of the hole have wood removed, not the front or back of the key. I prefer the Yamaha tool since it leaves what wood there is there, and eases the inside of the hole to the correct contour from the insides of the hole. Check for looseness at the front/back of the balance hole by pulling gently at the front of the key. If any looseness is evident, then repair the hole area.

8) CHECK BUTTONS, EASE OR REBUSH AS NEEDED

After the balance hole is made to fit, correct any problems with the balance rail button bushing. If too tight, ease with key easing pliers. If too loose, rebush. The correct tolerance is 0.1mm-0.2mm lateral movement.

9) CHECK KEYS AT FRONT RAIL PINS, EASE OR REBUSH AS NEEDED

Similar to the balance rail, ease if too tight, rebush if too loose. Check with the key in the down position. A 0.3mm lateral movement is correct.

10) CLEAN AND BUFF KEYTOPS AND FRONTS

Clean the tops of the keys with a moist cloth, using a little mild dishwater soap if need be. Buff lightly on a clean buffing wheel if desired. To make the plastic feel more like the old ivory, sand down the keytops lightly with 0000 steel wool or wet/dry sandpaper.

11) SQUARE KEYTOPS, CHECK FOR WARPAGE

Using a straightedge upon the key tops, checks for tilting. If not square, take a blunt object against the balance rail pin and bend until the key is square. If the key is warped badly, steam to bend it back.

12) ADJUST KEYHEIGHT AND LEVEL ALL KEYS

If the manufacturer’s specifications are available, try to use the given key height. Where no measurements are given, or if the given height does not work, then the correct keyheight can be figured out. Use an end key #1 or #88 and regulate it completely to make sure everything will work out right. Remember that the key can not be so high as to interfere with fallboard, nor can it be so low that inthe down position the keytop hits on the key slip. The key height should be positioned so that: 1) there is clearance under the fallboard and the underside of the key is not showing at the keyslip in the up position, 2) the key pins still have space showing the top of the balance pin and the key has about 3/16 – 1/4” of the front rail pin inside it in the up position, and 3) in the down position position there is enough key pin left to work with the punchings to achieve aftertouch. You may have to change the thickness of the backrail cloth if conditions 1, 2 & 3 cannot be met. After the correct key height is worked out, level all 52 white keys to this height, using either a beveled straightedge to make the middle keys a little higher, or a regular straightedge to make all 52 the same. Then set the correct height for the sharps, as will be dictated by the type of sharp used. Normally this measurement is 1/2”, from the top of the natural to the top of the sharp. However, some sharps are not this tall and if set at 1/2” would allow the wooden key to show through. Adjust accordingly. Remember that the sharp should be approximately 1/8" above the natural in the down position. Small adjustments can be made if the keys and stack are on the key-frame. Just cut a slot in the correct size punching and by turning the keyframe up and lifting the key and felt punching up slightly, slide the cut punching onto the key pin. When setting the key height, depress the key often so that all of the punchings are pressed down to the bottom of the key pin.

13) LAY DIP

My preference here is to make sure that the dip is deep enough to provide escapement during the rest of the regulation. I will correct this when I later adjust for aftertouch. If this system seems awkward, then set the dip using a key dip block. Whenever adjusting the punchings, always leave the felt punching on top and graduate the paper punchings so that the thickest is on the bottom.

14) SPACE KEYS

As the last procedure in this section, make sure that all of the keys have an equal amount of space between them. In bending the front rail pin to space the keys, lift the felt punching and bend the pin at the bottom. That way if the bending tool does put a nick in the pin, it will be in the area where the punching is and not up higher where it would cause the key bushing to wear. In spacing the sharps, remember that it is more important for the key to be spaced properly and to not rub on its neighbour than it is to be perfectly squared. This grand regulation guide will be continued in the next post.

GRAND REGULATION - A CHECKLIST - PART 2

Last week we talked about a 50-point checklist and knowing what changes are taking place during action regulation. A three-question quiz was also given which will be repeated here:

1)    Does regulating the jack height to the balancier affect the strength of the repetition spring?

2)    Does regulating the let-off affect the backcheck distance?

3)    Which of the following affect the amount of aftertouch: key height, blow, jack alignment, jack height, let-off, drop, backcheck, repetition spring?

Now that a month has passed to think about the answers, wouldn’t it be great if there were some place to turn to look up the correct answers? How many of us have taken the time to thoroughly investigate and think out what happens in grand action regulating? Everyone should own or have access to a grand action model. These are a great help in trying to figure out a problem or to understand the hows and whys of the working parts.

Here is a grand regulation chart which lists the nine action regulation steps and how they directly affect each other. (You can find the chart at the bottom of my last post. It’s the 2^nd graphic.) X’s mark steps which are affected, O’s mark those which are not.

It should now be quite easy to find the answers to the quiz. The answer to question no 1 is yes. Think of the butterfly type repetition spring as now used in Bosendorfer, Steinway, and Yamaha grands. As the balancier is raised or lowered to the correct height above the top of the jack, the tension on the repetition spring is changed. Think of the balancier and whippen as opening and closing like a jaw. The tension on the spring increases as the balancier is lowered. However, the effect this style of spring has is the opposite one would expect. Even though the tension increases, the hook of the spring moves forward (toward the keyboard) in the spring slot on the bottom of the balancier. This necessitates the spring tension to be increased in order to achieve the same effect, since the point of contact is now further from the balancier’s flange.

In answer to question no 2, the grand regulation chart is marked no. Now it is possible to argue that if the key is depressed slow enough, as when we regulate the let-off, and if the let-off is changed considerably, that the hammer will check at a different height. True, but the main factor here is not the let-off distance. Rather, the speed at which the key is depressed. In actual playing, the hammer must continue to move upwards after let-off in order to strike the string, then it falls back, going into check Changing the let-off only changes the amount of power that the key gives the hammer. The backcheck distance does change, of course, on whether the player gives the key a hard or soft blow. On a hard blow, the hammer rebounds more forcefully into the check position and ends up a little lower. On a very light blow, the hammer may not even go into check. Anyway, we can be pretty safe if the backchecks are regulated before the let-off, since as can be seen on the grand regulation chart, the backchecks only affect the repetition spring strength.

For the third question, the factors which affect aftertouch are:

1)    Key height. Changing the key at the balance rail affects the key at the front rail by a factor of about 1:2. Adding a 0.010 balance rail punching will increase the dip, and hence the aftertouch, by about 0.020.

2)    Blow. Piano actions are designed so that the dip to blow ratio is about 1:5. Changing the blow changes the amount of key dip needed for total escapement. When we raise the capstan to lessen the blow distance, the effect of raising the whippen puts the jack tender closer to the letoff button and the end of the balancier closer to the drop screw. This causes escapement to happen sooner in the stroke of the key, giving more aftertouch.

3)    Jack alignment to the knuckle. Since the jack has a double function of raising the hammer and also causing let-off, regulating the jack to the knuckle changes when the jack tender engages the button. Therefore, if the jack is moved inward, toward the keys, the tender moves down and away from the let-off button, creating escapement later in the dip, meaning less aftertouch.

4)    Let-off. From what has already been said, it is obvious that let-off directly influences aftertouch. Making the let-off closer to the string creates less aftertouch.

5)    Drop. If drop is defined as the amount that the hammer drops after let-off, and that aftertouch is defined as the downward movement of the key after drop, then the amount of drop is proportionate to the amount of aftertouch. Decreasing the amount of drop increases the amount of aftertouch.

Notice that on the grand regulation chart the first left to right column is marked dip. This is the column which is read for aftertouch, since aftertouch is a part of dip. The factors which do not affect aftertouch are the jack height, backcheck distance, and the repetition spring strength. Of course, the jack height and repetition spring indirectly affect the aftertouch by affecting the hammer blow distance. But this chart only shows direct relationships.

Having answers to questions like these is a great help in figuring how to approach the specific action at hand. Remember last week’s post that the order of section IV “The Touch” of the 50-point checklist may be changed to suit the needs?

IV. Touch

31) Jack height to the balancier

32) Blow

33) Let-off

34) Drop

35) Aftertouch

36) Backcheck distance

37) Repetition spring

38) Check gram weight resistance all 88 keys

39) Adjust key stop rail 

This order would be fine for dealer preparation on a new piano. But what about an old action where the repetition springs are weak? (Remember “the circle of five steps”? See the 1^st graphic in my last week’s post.) Then the jack height will vary each time the key is played, making it impossible to set the hammer line straight. In this case we could not begin with setting the jack height and blow distance. Rather, we should start with the backcheck distance and go immediately to strengthening the repetition springs. A quick glance at the grand regulating charts shows that only two steps affect the backcheck distance. One is the key height which was set in step #12 on the checklist. The other is the dip. So after setting the dip be sure to go back and readjust the backchecks! See how easy it is with the proper information at hand? Now you can start with setting the jack height and blow and go on as is listed in IVTouch.

Remember in selecting the proper sequence in this IVTouch section that those steps which affect the others the most should be completed as soon as is possible. In reading the far right-hand total column we see that the key height and blow affect four other steps versus only one or two for the other procedures. Therefore, try to adjust the key height and blow first. Similarly, make sure that the dip is one of the last steps to be completed, since as seen in the bottom column, five other steps affect it.

Now that we have a grand regulation chart which shows how each step affects and is affected by another, we can use it as a check while going through the 50-point checklist. A checkup and a check! If we go one step further and put them both together along with a “how to”, an excellent guide will be created which will help anyone through regulating a grand action. Coming up in the next post, an enormous 50 - point guide to grand regulation.