hammer butt springs

[Jim_Harvey@yca.ccmail.compuserve.com]

     At the time I picked up mail, there were no responses to this inquiry,
     so here's my chance to sneak one in. I'm glad to see that you care
     enough to want to do this job correctly.

     This is up my alley, since it involves time and motion procedures more
     than intelligence. It might be tough using words only, but here goes:


     REPLACING HAMMER BUTT SPRINGS (SET)

     Tools/Materials

     1.Quantities of _all_ sizes of replacement springs that your supplier
     offers. Be prepared to modify these. Also be prepared to custom-make
     replacements in spite of this, when _none_ of the supplier's springs
     work.

     2. Replacement "spring rail" or "damper stop rail" felt.

     2. * Soaking solution (Shaklee Basic 'H' recommended in this instance);
        * spring-making tool and/or small curved-nosed plier
        flush-cutting diagonal plier;
        spring hook;
        dental/other "pick";
        Kelley forceps (hemostats) or small plier;
        length of steel rod (3/32"? or dia. of wire clothes hanger);
        small scraper (sharpened)
        small cold chisel;
        small hammer
        glue (hot hide preferred, otherwise the other stuff).

        *  (MAYBE -- see text)


     Procedure:

     1. Remove existing spring rail. (On compact actions, it helps to
     remove hammer rest rail first).


     2. Tear off or pull back enough old "spring rail" or "damper stop
     rail" felt far enough to remove a sample.

     3. Carefully bend spring tongue (stub) straight and remove an intact
     spring as sample. (Important, because your replacements may not be the
     same exact length and/or diameter).

     4. Tear off existing felt and scrape rail on older actions;
     tear/soak/scrape on newer. Allow to dry thoroughly if soaking is used.

     [Note: If an additional small strip of felt (no nomenclature) is
     touching existing spring coils, remove and _don't_ replace it. I can
     only rationalize that this "spring coil felt" was installed to
     correct a a problem that didn't exist. In any event, on newer pianos,
     this felt is the _cause_ of spring failure.


     5. The fun part: use hemostats or pliers to extract old springs. If
     stub end breaks, use small pick to remove all spring stub remnants
     from channel. Use pick to 'debur' spring channels.

     6. If replacement spring diameter is _slightly_ larger, use drill bit
     to ream holes in rail. Otherwise, use appropriate bit or awl to debur
     existing holes. (Note: if diameter or other dimension of replacement
     springs is considerably different than originals, consider making
     replacements -- it's not that tough a job.)


     7. If "working" length of new springs needs to be modified to agree
     with sample, cut and make new loop pattern at ends. Gang-style, not one
     at a time).

     8. Install _all_ springs into respective holes. Cut new spring stubs to
     match sample, and/or to fit. Criterion is that excess spring stubs do
     not hang out below bottom of spring rail, and that stubs will be fully
     covered by new spring rail felt. Do _not_ make them even with bottom of
     rail -- they may "grow" a little during subsequent steps.


     9. Insert section-length rod through spring coils to maintain
     straight-line coil symmetry.

     10. Press each coil in section firmly against spring rail (front of
     action rail); bend stubs down _sharply_ into channels at rear with a
     hard-edged tool (fingers make too gentle a bend). Repeat steps 9-10
     for each section.

     11. When all springs are installed and stubs bent into position, lay
     rail against edge of bench with springs hanging off. With cold chisel
     and hammer, lightly seat spring stubs into channels. Repeat at
     90-degrees to channels to close wood around spring stub. (Sometimes
     tapping at original factory mark works -- sometimes it doesn't).


     12. Apply new spring rail felt, cut to correct length.

     13. Rough adjust tension by pressing _all_ spring ends (by holding rail)
     against top of shop bench. New springs usually have too much tension, so
     first effort is usually to _reduce_ tension.

     14, Reinstall rail into action. If tension is excessively too
     little or too much, remove and adjust course tension per step #13.

     15. After satisfied with course adjustment, fine adjust springs using
     traditional regulating methods.

     Note: Some actions have the spring stubs doubling back through a second
     hole. This procedure eliminates the need to duplicate that condition.

     I hope this works as a top-down procedure. It's the best I could do on
     short notice.


     Jim Harvey, RPT
______________________________ Reply Separator _________________________________
This may be "old-hat" to most of you, but (believe it or not) I've never
had occassion to replace a set of hammer butt springs. I have that occasion
now, and would sure appreciate any pointers you might offer on gettin'
those little wire thingees into that there stick thing (or do they grow
that way?). Seriously, please, any tricks I need to know?

Bob Simmons, RPT