Bob O'Ling Hammerz

[Larry Fisher]

I recently spent some extra time on a Samick/PianoDisc installation because
I wanted to learn about actions and all that is related.  I'll set the
stage......

5'1" grand, tefloned key bushings and knuckles, full regulation, alcohol and
water the middle 6 octaves or so of hammers, player mechanism plunger height
adjusted for maximum stroke (very little preload), and the area of
contention is right smack dab in the middle, around middle C and about a
half octave either way.

The symptom is bobbling hammers on soft playback with the electromechanical
(PDS) but plays great by hand.  I picked a few notes that were really
bobbling bad and studied them.  I measured the hammer flange to whippen
flange and got just under 4"........ 3 15/16.      I didn't have a metric
scale.  Not knowing what the spread was supposed to be, and being 9:00 PM I
couldn't really call anybody, so I was left to my own devices to try and
cure this beast.  I tried roughing the tails, changing the angle of the
backchecks, (radially and the other way), drop, let-off, repetition spring
tension, damper lift, hammer height, plunger height (PDS), and I even
changed the proccessor chips on the driver boards.  I even tried the jack
position under the knuckle, setting it to just that point when it would fail
on a strong blow if I adjusted it any further.  As near as I could see the
knuckle was bouncing off the jack, or the rep lever and the backcheck wasn't
doing it's thing properly.

After trying everthing I could think of, I coved the back of the hammer.
Between the roughed up area of the backcheck catching area and the hammer
shank, on the underside, there is some wood that can be removed, not much
but a little.  I fired up my Dremel with a drum sander bit and removed that
small amount.  I vaccuumed up the mess and re-installed the action.
Presto!!  I had checking, and what bobble I had was so small that it didn't
hit the string a second time.  I then did the rest of the hammers in the
area and had success on each occation.

Would anyone care to expound on this??  Samicks are being marketed under
lots of names, and if I don't learn how to cope with their peculiarities, I
guess I'll have to cope with a bit of buyer's remorse from the customer.
I'd prefer to master their actions and understand their (I hate using this
word) inadequacies.  Or is it me that's inadequate??

Lar



                           Larry Fisher RPT, Metro Portland, Oregon's
                  Factory Preferred Installer for MSR/PianoDisc Products
                       phone 360-256-2999 or email larryf@pacifier.com
                            http://pacifier.com/~larryf/homepage.html
                         Beau Dahnker pianos work best under water