Prepare mask and hair coverage before refinishing, make sure there no change for dust or hair to fall off onto surface being sprayed. Read instruction carefully and double check refinishing supplies are accurate and enough for the work. Clean spray guns thoroughly before staring to measure the liquid.
This Yamaha upright piano has excessive lost motion between capstan and wippen. This is the main cause of hammer double/multiple strike on strings or bobbling hammers. Taking up the lost motion by turning up capstans eliminates this problem.
On this grand piano, some jacks are rubbing on either sides in repetition lever windows. When keys are played, the rotating jack-rubbing-window motion creates big clicking like noise.
The jack center pins need to be bent to let top of jack centered to the window. Support bottom of center pin on hard surface on the side where the bend shall be, whack top of jack with a hammer till it is centered. In order not to over do it, not too much force needed for each whack. After a couple of adjustments, one could only find way more jacks to be whacked...
One this upright action, all sorts of clicking noise are present. Turns out that all the action screws are loose includes: hammer flange screws, wippen screws, and damper screws.
From left to right, tighten hammer flange (butt) screws, wippen screws, and damper flange screws. Noise is gone after this process, took about 30 minutes. The piano owner was so happy, so did the piano technician ^ ^
The marron colored hitch pitch pin felt needs to be replaced. There are so many holes on it to be transferred on new felt. For accuracy and better fit, the shop owner suggested that we use mylar as a templet. With a good hands on skill, the mylar step can be eliminated, not here, though...
The plate has been refinished, all shiny shiny. Spray adhesive on back of old felt, glue it on a piece of mylar or similar material that's on the stiff side. transfer holes through old felt to mylar, try on plate for fitting. If some holes don't fit, mark and re-punch holes till the template sits flat in position. For the missing holes on old felt, the mylar is placed on top of those hitch pins, a pencil is used to rub from top to make a mark for the punch.
Spray adhesive on top of template, glue new felt on so the glue is on the bottom of the new felt. Flip up side down so the mylar is on top now, transfer all accurate holes to new felt, fit again on plate. Glue down the two ends with felt glue. The rest of the felt will be pressed down by strings.