Grand Regulation In Detail - Part 7

Last discussed in the 50-point guide to grand regulation were the two main methods to regulate. One is called the Blow Priority method, the other is the Dip Priority. To determine whether a given procedure is Dip or Blow Priority, just look to see which of the two is regulated first in the order of steps listed. Once the dip or blow has been adjusted, all of the other action regulations are then set based upon this first measurement.

To explain this further, there are seven main steps in section IV, The Touch portion of the 50-point checklist These seven are: 1) Blow, 2) Dip, 3) Let-off, 4) Drop, 5) Backcheck distance, 6) Repetition strength, and 9) Jack Height to the balancier. Again, as in the past, the dip includes the correct aftertouch measurement. Let us take the example of a Blow Priority system first. If the repetition spring is strong enough to support the hammer first adjust the jack height in order to insure that as the blow is set that the hammers will always return to the same setting. Step two then would be to set the predetermined blow distance.

Depending upon how worn the whippen felt is, how flattened the knuckle has become, and how much the hammer has been filed the capstan will need to be raised further to compensate for greater wear in order to achieve the desired blow distance.

Raising or lowering the capstan affects directly or indirectly all of the remaining steps. Raising the capstan raises the whippen assembly, which causes the jack tender to become closer to the let-off button, and the balancier to become closer to the bottom of the drop screw. Once the let-off and drop are correctly set, changing the capstan will necessitate readjusting the let-off and drop. If the correct after-touch is to be achieved, the dip measurement is predetermined by the blow and let-off distances selected. The amount of dip will affect the backcheck angle. And, as we all should know, we set the repetition spring strength based upon the hammer’s release from the backcheck. So out of the seven main steps in section IV TheTouch, changing the capstan will affect one way or another all seven steps: To eliminate any unnecessary doubling back to reregulate a step already performed, set the blow distance right in the first place, and all of the other six steps will come out correct the first time through.

Remember the “circle of five steps” as explained in the first article of our series on grand regulation? If not, please look again at our first post. This illustration helps to show how each step affects the others.

 

Adding the let-off and drop in between the blow and the dip completes the circle with all seven steps. Of these seven, only two can be places of compromise to compensate for action wear. The let-off, drop, backcheck distance, repetition spring strength, and jack height can only be regulated to specific tolerances or distances, with very little room for variation. Only the dip and blow can compensate for action wear. The Dip and Blow Priority methods are the means of setting one of these variables in the beginning, making any compromises needed with the other variable latter.

One school of thought amongst piano technicians is that the dip is not a variable. In other words, there is a specific measurement that the key is supposed to go down, that measurement being standard throughout the world, and no variation from that measurement (usually 3/8”) is acceptable. This of course leaves only the blow distance as a means of compromise as the action wears. I believe this school of thought to be a little narrow minded. There are times when the dip should be altered a little. When I say a little, I mean within + or - .036” at the maximum. Next week, we will discuss just how “‘standard” this measurement is.

We have already discussed what the main areas of wear are: 1) ...

Read more:

https://www.professionalpianotunerlondon.co.uk/post/grand-regulation-in-detail-part-7

 

 

Grand Regulation In Detail - Part 6

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  ...

Read more:

https://www.professionalpianotunerlondon.co.uk/post/grand-regulation-in-detail-part-6 

 

 

Grand Regulation In Detail - Part 5

Section III. Alignments

27) Align hammers to strings

 

To facilitate this alignment procedure, install the action into the piano andmake 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 ...

Read more:

https://www.professionalpianotunerlondon.co.uk/post/grand-regulation-in-detail-part-5

Grand Regulation In Detail - Part 4

II. THE TOP ACTION (off the keyframe) - continued

22) Clean repetition spring and groove (Steinway, Yamaha, Bosendorfer). On Steinway, Yamaha and the Bosendorfer whippens (which have the butterfly type repetition spring), the spring grooves are coated with a graphite solution. The Yamahas now use a teflon coating here, but the older models of this type whippen are graphite.

Hurray that someone has finally seen the light! This graphite paste becomes dirty and gummy, and makes for a source of friction instead of eliminating it. These grooves in the underside of the balancier and the spring tips must be cleaned in order to achieve a good regulated action. If left uncleaned, the jack height is very hard to set since the repetition spring not only has to support the knuckle, but also has to overcome this messy graphite paste as the balancier moves.

To clean this groove, release all 88 repetition springs from the grooves and turn the action upside down, taking care to protect the hammers while doing so. Run a piece of cloth up and down the grooves until clean. Be careful not to damage the groove. Now choose a lubricant which will, hopefully, eliminate this problem during future use. I have tried three different lubricants for this job, but I have reservations about all three of them. If any of the readers have a sure-fire method to solve this problem, please be kind enough to share it!

I have tried:

1) Dag 154. This is a graphite solution and works well for lubricating the spring. I question whether it will be free from the dirty, gummy mess which plagued this area in the first place.

2) Spray teflon. I feel that this teflon is not as good as what is available to the manufacturers. It does not seem to last. Hence, the repetition spring, while not getting dirty and gummy, will also not be lubricated quite well enough.

3) White grease. This is supposed to prevent rust and corrosion on the spring. It is not absorbed into the wood, but it is bound to get dirty with time. As to whether it will also get gummy and inhibit the spring is anybody’s guess. The ideal would.be to apply a teflon coating like what Yamaha now uses, but to my knowledge this is not available to technicians.

Turn the action right side up and clean the tips of the repetition springs with a suede brush. Rebend the springs back into their grooves, making sure that the spring is indeed in its groove by applying as light sideways motion.

23) Round whippen felt if needed. The cushion felt on the bottom of the whippen which rests upon the capstan always compacts and gets worn from the constant hammering of the capstan hitting against it. Incidentally, this compacting along with the flattening of the knuckle is why a new piano always loses its hammer line. In the case where these parts have only “settled in”, the action can be brought back into regulation by raising the capstans and making the corresponding adjustments in the let-off and drop. Since raising the whippen puts the jack tender closer to the let-off button and the balancier closer to the bottom of the drop screw, these two must be changed.

I use two wear areas, the knuckle and the whippen felt, to decide whether to repair an action or to replace the action parts. Just like a flattened knuckle, a worn whippen cushion felt must be ...

Read more:

https://www.professionalpianotunerlondon.co.uk/post/grand-regulation-in-detail-part-4