Hammers stick when the center pin is too tight in the flange.  The bushing in the flange often expands.  Some tuners oil at the ends of the pin with kerosene or wet it with alcohol, which is very good; but a better plan is to shrink the bushing with a drop of water on each side so that it will penetrate the bushing.  After this is done, the piano cannot be used for a day or two, as the water first swells the bushing, making all the hammers stick; but when they are dry again, they will be found free.  This may seem a curious method, but you need not be afraid of it; it is the most effective.

Before leaving the hammer butt, see that the hammer spring is in its place.

8. Hammer Stem.—­These sometimes warp, split, crack, or come unglued at the butt or hammer.  If twisted so far that it does not strike properly on the strings, or that it binds against the next hammer, the best thing is to put in a new stem.  If merely split or unglued, it may be repaired.  Sometimes a click is heard and it will seem impossible to find the cause, the hammer and stem apparently perfect, but a close examination will reveal a looseness in the stem somewhere.

In putting in a new shank, drill or chip out the old one, scrape the holes out clean, take your measure carefully, and do not make the new shank too tight, but large enough to fill the hole snugly.  Apply glue to the ends of the shank and also in the holes.  Cedar is used in some makes, but good maple is stronger, and is more generally used.

9. Hammers.—­When too hard, soften with a felt pick.  Do not raise the felt up, but stick the pick in the felt just back of the point and this will loosen it up and make it softer and more elastic.  Where the strings have worn deep grooves, sandpaper them down nearly even and soften the felt as above.

In regluing the felt to the head, glue only the back ends of the felt, and clamp with strong rubber band till the glue sets.  Use tailor’s chalk (fuller’s earth) to clean hammer felts.  To harden or draw felts back in shape, place a damp cloth over them, and then pass a hot iron over it.

10. Dampers.—­Damper felt often gets hardened so that when it comes against the vibrating string, it causes a sort of buzzing sound.  Loosen it up with the pick.  Imperfect damping can sometimes be corrected in the same way.

The damper head sometimes turns round on its wire, leaving one or two strings undamped.  Tighten the set screw.  See that the dampers are in line; and that they will stop the tone properly when the key is released.

Damper springs sometimes break.  It is necessary to take out the damper lever to put in a new one.

See that the spoons are in line and work properly.  Press the sustaining pedal down, and see if all the dampers are in line; if not, bend the damper wires with the regulator until they line up perfectly.

11. Damper Rod.—­When the sustaining pedal squeaks, look first to the pedal, then to the wooden rods leading up to the damper rod.  If the trouble is found in any of these, or the springs, use sperm oil or vaseline.