GRAND REGULATION – part VI

Section III. Alignments

29) Align jack to knuckle core

In order for the power to be transmitted from the whippen to the hammershank efficiently, the jack must be properly aligned under the knuckle. 

Looking at the action sideways, the rear of the jack (the surface towards the hammer) should line up perfectly with the rear of the knuckle core. Normally, this alignment is easy to see. The knuckle should be glued on perpendicular to the shank, and if the hammer is new and was bored correctly, the shank should be perpendicular to the jack. Sighting along the rear of the jack, it should be easy to tell when the jack is in line with the knuckle core.

However, if the shank is not perpendicular to the jack this alignment is hard to see. Two things can cause this:

A. The hammer has worn resulting in the capstan being turned up to keep the blow distance close enough. The shank then becomes more than 90 degrees from the rear of the jack. In such cases, imagine a line drawn from the rear of the knuckle core down to the point on the knuckle leather where the jack would touch it. Then line up the rear of the jack to this point.

B. The other reason, which is fairly common, is that the hammer hole was not placed correctly in the molding. This results in the top of the hammer, either, being too high, or too low in relation to a line drawn down the middle of the hammershank.

Boring the hammer wrong of course results in the shank not being perpendicular to the jack as in cause A. If this angle of the shank to the jack becomes too great, then either the hammer has worn excessively so that it should be replaced, or if the hammers are new, then the hole in the molding should be plugged and rebored.

Why was the hammer bored incorrectly? Have you ever noticed when regulating the hammer-blow distance, that when the tops of the hammers are adjusted so they all are, say, 1 3/4” from the strings at rest, that the hammers in each section vary as to their heights measured from the keybed to the top of the hammers?

We should expect the bass hammers to be higher since the bass strings are higher so they can cross over the tenor strings. But notice that if the agraffes are not the same height as the capo d’astro, the hammers will also vary in their heights between these sections.

If the original or duplicate hammers were not bored taking into account these different string heights, then the hammershanks will not be perpendicular to the jacks with the hammers at rest.

We will discuss this problem further in a later post on hammers, but let me add here that some pianos have a different string height for each section!

An easy way to align all of the jacks is to align the end hammers in each section, and then by using a straightedge or a thread, align the jacks in the respective sections to the end samples.

Note that some manufacturers mark a line on top of the balanciers. This line serves as a guide only when the action parts are being assembled in the factory. If it is necessary to deviate from this line, don’t hesitate.

To test the jack alignment, hold the hammer with one hand to keep it from coming up, and with the other hand, give the key a strong blow. If the jack is too far in or out in relation to the knuckle core, the jack will slip out from the force of the blow given to the key. This test should be given to all 88 keys.

When the knuckles are all in a straight line, and if all of the jack tops are also in a straight line, this test should prove out on every key.

But many pianos made today do not have all of the knuckles lined up perfectly, some being out of line by an 1/8“! For these pianos, the jacks must be individually aligned to their respective knuckle cores.

Remember in replacing a whole set of shanks and flanges, the knuckles must be the same size as the original, and the distance from the centre pin to the centre of the knuckle core must be identical.

30) Align and square backchecks to hammer tails.

To facilitate this regulation, turn the action around so the backchecks are facing you. Individually lift the end of the key and wait for the hammer to come into check. Don’t lift the key so forcibly that the hammershank is marred by hitting against the drop screw, or actually broken off from the impact! Look to see if the hammer tail is caught in the middle of the backcheck and that the backcheck is square and aligned to the hammer molding.

To correct the side-to-side alignment, first bend the backcheck wire at the bottom to the right or to the left as needed, then bend it at the top to square the backcheck with the tail. This procedure is the same as when bending damper wires.

Check to see if the backcheek is turned or if the hammer tail was not filed properly on angled hammers. The two should be adjusted or filed so the stress on the key when the hammer goes into check is in line with the key itself.

Some imported pianos from Asia were made with the backchecks turned to meet the angle of the tails in the bass and tenor sections. This stressed not only the key bushings but also the hammer centre.

File these tails square to the ends of the keys as they should be, and turn the backchecks so they are square to the tails. If the tails are not filed properly, the protruding corner of the tail will cut into the backcheck leather in no time.

While aligning, make certain that the tails are roughed up enough to keep the hammer securely caught by the backcheck. I use 60-grit, open-coat sandpaper glued on to a hand file for roughing up old hammers. New hammers I rough up before they are glued onto the shanks. I would caution use of coarse files or moto-tool saw blades to roughen up tails, as these make the tails so rough they wear the leather out prematurely.

This ends the third section of our 50-point procedure. At the beginningof this series of posts about grand regulation, I mentioned that section IV, The Touch, was the most variable part of the regulation, and that depending upon the needs of the action, the sequence may be changed.

In the first post on grand regulation, I included a chart which shows how the different regulations of The Touch affect or are affected by the others. A quick glance at this chart reveals that three steps: A. the key height, B. the key dip, and C. the blow distance affect or are affected by the others the most.

Before we begin talking about all the steps in section IV, let us discuss how to get the correct relationship of these three steps. Without doing this first, the regulator can waste many hours on section IV trying to figure out why the action does not play at its peak performance.

Way back in step 12 in section I, we adjusted the keyheight. All that remains here is to adjust the blow and the dip. l will explain two methods to regulate a grand piano. One is the blow-priority method; the other is the dip-priority.

I contend that once the keyheight is set, one only needs to set the dip or the blow, and the remainder of the action can be regulated to peak performance, straight through, with little or no doubling back to alter previously set measurements. In the next post, we will continue with a discussion of these two methods.

GRAND REGULATION - part V

Section III. Alignments

27) Align hammers to strings

To facilitate this alignment procedure, install the action into the piano and make a rough check of the let-off measurement. If the let-off is very far from the strings, the hammer-to-string alignment will be very hard to make. So try adjusting the let-off by say one-half or one complete turn of the adjusting screw and see what number of turns it takes to get the hammer to let-off right next to the string.

At this point in the regulation procedure, if the hammer blocks on the string, it will be all the easier to make the alignment. Then remove the action and turn all of the let-off screws the number of turns that you found necessary to get the hammer closer to the strings.

Before starting to centre the hammer to the strings, make sure that the hammers have been filed, removing all traces of former string grooves. If the piano has agraffes, then your job will only be to align the hammers to the strings. If the piano does not have string aligning mechanisms throughout, then you must make sure that the strings are properly spaced and centred before attempting to align any hammers.

Normally, unless the plate has been repositioned or a bridge reglued onto the soundboard, there should be a straight line running from the hitch pin through the bridge pins and on to the tuning pin hole in the plate. The middle string of a trichord should run along this line, with the right and left strings having the same inward pointing angle, since the bridge pins are wider spaced than the spacing at the V bar.

Begin aligning the hammers to the strings by taking a wire hook and coming down from the strings, lifting the shank so that the hammer blocks on the string. Or, take a finger and lift the bottom of the whippen taking the hammer past let-off and pushing up until the hammer again blocks on the string. I prefer the latter method since the wire hook is slower and can cause the hammer to be pulled to one side if you are not careful.

Looking directly above the hammer, check to see, if it is properly centred to the strings. For a trichord, equal amounts of hammer should be seen on both sides of the unison. On single or double unisons, the hammer can either be likewise centred, or they can favour the bass side a little, depending upon how you want the hammer to strike when using the una corda pedal.

Any hammers which are properly centred on the strings, I mark with an “O” on the key with a piece of chalk. Those which are off to one side, l mark with a straight line on the key to the side which they need to go, varying the thickness of the chalk mark as the amount the hammer needs to be moved. Do one section at a time.

Pull the action out after chalking all of the keys, and compare the marks with the way the hammers look. All of the chalk marks must coincide with either a perfectly centred hammer or else a hammer that needs to be traveled, angled, spaced, or a combination of these three.

Place a long screwdriver blade or other object such as a spare pedal rod under all of the shanks in this section and check the hammers first for traveling. Even though a key was marked “O” the hammer may be traveling or have the incorrect angle. After correcting the traveling, heat the shanks of those traveled along with any others whose angle needs to be changed until all of the hammer angles look uniform. Lastly, space the hammer by slightly moving the flange sideways.

If the flanges are of the type where a screwdriver or flange spacer can be used, install the action into the piano and space the flanges directly by lifting up the hammer until it blocks on the string. If the flanges are not of this type, then they must be spaced outside of the piano. Use the width of the chalk marks as a guide to how far to move the flange, and try to use any keys marked with the “O” as a point of departure.  

I get two keys about five or six keys apart marked with the “O” and work from these, putting t action back into the piano and making any needed refinements.

Remember that some manufacturers have a two degree tilt hammer on the shank. The more the hammer was bored at an angle to match the angle of the strings, the more likely it is the hammers will have to be tilted on the shank to properly space the hammer to the string and to make sure the tails do not interfere with the adjacent hammers.

Centre all of the hammers in each section in the manner shown. If someone altered the plate sideways, for instance when installing a new pinblock, or if a soundboard was replaced and the bridges are a little off to one side, good luck!

28) Align and square whippens to the knuckle

Ideally, when the shank and flange assembly is made, the bottom of the flange should be perfectly flat and the birds-eye be drilled correctly so that the centre pin is perfectly horizontal. The shank bushings should be perfectly fitted so that the bisects the shank, and of course, the knuckle should be ungrooved and perfectly round, being glued onto the shank squarely. Such an assembly would have no need to be traveled, making the knuckle tilt the one side. Sweet dreams.

What happens when a tilted knuckle receives a strong blow from the jack? If the jack is also at the same tilt, very little power is lost, and rather little wear results. But when the jack is not on the same plane as the knuckle, power is lost and abnormal wear results. Every time the jack hits the knuckle, the power from the key is transmitted by the tip of the jack to the knuckle, not by the whole top surface of the jack. Power is lost here. Worse yet, the jack centre pin and bushing take a beating. Likewise, the knuckles wear at one spot since the corner of the jack inflicts the blow. The shank then is given a twisting motion at the centre pin instead of an even straight blow, again resulting in a loss power and abnormal wear to the shank bushing. The best relationship is when the whippen and thereby the jack is tilted to match the tilt of the knuckle.

Granted, tilting the whippen results in the capstan no longer hitting the whippen felt squarely, and the whippen centre pin and bushing get a little twisting motion. But remember, the capstan is rounded, so the whippen felt is not abnormally worn. Also, keep in mind that the arc of travel for the whippen is far less than the shank, and the whippen centre pin is further from the transmission of power than the hammershank centre. The lesser of evils is definitely to tilt the whippen.

Therefore, when spacing the balanciers to the knuckle, look at two things:

1) Does the tilt of the whippen need to be changed to match the tilt of the jack?

2) Should the whippen be moved sideways to keep the capstan centred under the whippen felt?

If tilting the whippen aligns both the knuckle to the balancier and the whippen felt to the capstan, all is well. But, if tilting the whippen puts the knuckle in line at the balancier and not the capstan at the whippen felt, then compromise. The balancier must always be centred with the knuckle, even if the tilt of the jack does not exactly match that of the knuckle. The capstan can be a little off to the centre of the whip much as to cause the capstan to be on the edge of the whippen felt.

To tilt the whippen, loosen the flange screw and tilt, then retighten the screw. Sometimes the flange must be papered underneath on one side. To space the whippen sideways, remove the flange and paper the flange on the side that you wish the whippen to move. This is the opposite to papering a hammershank flange. For ease in removing the whippen flanges, it is best to remove the hammer rest rail first, if there is one.