----- Original Message ----- From: Gerald Posey <poseyviolins@charter.net> To: <pianotech@ptg.org> Sent: Sunday, March 10, 2002 3:53 PM Subject: more beginner questions > I'm working on regulating the action of a Heintzman baby grand. All my > reference drawings show two separate springs for the jack and escapement > lever but this piano has only one that seems to do both jobs. There is a > little tiny screw at the end of the escapement lever(away from the roller). > What does it do? I made all of the measurements for key leveling and dip, > hammer travel and "where the jack trips". But the touch feels "vague" like > theres no power. When they say , "the jack trips" do they mean it begins to > move or it is all the way out of the way? > Thanks > Gerald Before you regulate anything, you have to have some drop and some repetition spring strength. The little screw at the end of the repetition lever (escapement lever, or balancier) could be for adjusting the height of the repetition lever above the tip of the jack or it could be for adjusting the strength of the repetition spring. If it's a spade-head type, and turns a little button on the bottom of the repetition lever, which you probably would have noticed, it's for the former. If it's a straight-slot type, and more of a set screw recessed in the wood, it's for the latter. I'm giving particulars before basics here, but: The tip of the jack should be below the top of the repetition lever by "just a hair", or a few thousandths of an inch. With the hammers at rest, depress the tip of a jack with a finger and let go. The hammer should dip down, or "wink", but then return to where it was. If it doesn't dip at all, turn the button on the back of the rep. lever clockwise. If it dips too much (more than 1/16 " or so), or if it dips and stays dipped, turn the button counterclockwise. This isn't all there is to it, but . . . . Strike a key and make the hammer rebound off the string or regulating rack and be caught by the backcheck. Now, without letting go of the key or letting it come back up, just release your pressure on the key, but still keep it touching the front rail punching. In other words, you're holding the key down with minimum pressure required to keep it down (hammer still in check). The hammer should rise up to its let-off point, if there's any repetition spring strength, with a "positive", or "assertive" motion (not a sluggish, gradual rise, and not a sudden, springy, jumping motion at the end of which it bounces, or "dances" . You shouldn't feel a little thump in the key when it rises.). If it jumps and dances, decrease the spring strength by turning the set screw counterclockwise. If it's a sluggish rise, turn clockwise. This is assuming you've already checked hammer shank pinning and taken care of any tight or loose ones, and that any slots the spring rests in aren't gunked-up with goo. There's much more to this, but it requires a lot more explaining and some "hands-on". As far as the jack tripping, it starts to trip as soon as its tail, or tender hits the regulating (let-off) button, but the key goes down several millimeters before it's all the way out from under the knuckle (roller). The hammer should go up to about 1/8" to 1/32" from the string, depending on various factors, before it drops away (lets off), after which it should drop about 1/16 ". There's a lot more to be said about let-off and drop, but no space here. As Wim said, the jack hitting the let-off button and the rep. lever hitting the drop screw should happen at the same time. As far a "vague touch", are all the action screws tight? Is the keyframe properly bedded? Are the hammers aligned to strings, wippens aligned to knuckles and wippen cushions directly over their capstans? Are the capstans polished and the wippen cushions clean? Are the jacks properly aligned to the knuckles? Is there gunk on the knuckles? Are the backchecks catching the hammers or is the leather on them worn out so that the hammers "bobble"? Are the backchecks retarding the hammers on their way up? (With hammer in rest position, restrain it with one hand and press the key with the other hand, and rock back and forth to see if the hammer tail rubs on the backcheck). This is just a start. Post is getting too long. Past my dtime. --David Nereson, RPT, Denver
This PTG archive page provided courtesy of Moy Piano Service, LLC