Checks cause hammer bounce ?

[RicB]

Hi Ron, and thanks for the good words of advice.

I am pretty sure I have the bedding good.  I use the method I've been 
taught at the Yamaha Acadamy, which involves learning how to hit with 
the butt of your palm at the bedding screws while putting slight 
pressure upwards on the top action with your fingers, or with the help 
of some tool to lift with.  Takes a bit of practice and I've seen some 
guys who just cant get it right... but for me this works quite well. 

This said... I've been wanting to try out your method for a while now, 
but cant seem to find a dial gauge like the one you mention... tho I 
admittedly haven't busted my left thigh looking for one :).  If you have 
an address handy I'd be greatful.  I'm dead sure I have good solid 
contact with all glide bolts tho. The only thing I dont know with any 
accuracy is just how much pressure each bolt puts on the bed.. tho I 
have them set so that they are not heavy to lift and get a knock.

Front rail is bedded perfect, and when the cheek blocks are down and 
tight I get no knocking.  Andre showed me that bit about Steinway frames 
a few years back.  Back rail I'm not 100 % sure of... but a long thing 
screw driver slipped inbetween keybacks, banging on the back rail did 
not reveal any knocks.  I do all my bedding with the action fully 
assembled btw.. no missing keys... no nothing to be able to change after 
the bedding is done.

One question tho... why would this symptom be the bedding screws ?  I 
mean... the only time the hammers bounce is when one comes hard into 
check... i.e. after the hammer has hit the string.  Its not like I'm 
loosing any power because of this... its just an annoying sensation... 
and ...well... grin I hate the look of bouncing hammers :)  On the other 
hand... with the key very firmly pushed into the front punching, and the 
back of the key in the air as it were.. a hammer comming down hard on a 
check ... well the key is a lever, and the balance rail is going to feel 
the brunt of whatever force the check has on the back of the key.  On 
the other hand again tho... if the balance rail was flexing... why would 
it do so ONLY upon the hammer hitting the check... ?

Cheers
RicB




    Ric,

    I've found that the symptom you describe is most often a bedding
    screw (glide bolt) adjustment problem. I'm probably mentioning
    something you already know, but since Steinway keyframes are made so
    that the front rail of the key frame springs up slightly at the ends,
    you need to clamp the ends down to the keybed before adjusting the
    glide bolts.

    The dial gauge method is unquestionably the last word for setting the
    bedding screws. The traditional paper shim adjustment method is
    highly error prone, even in the hands of an expert. Once, at a
    Steinway seminar at the Sydney Con in 1992, the visiting S&S tech
    showed us on the first day how to adjust the bedding screws using the
    paper method. The next morning I brought in my dial gauge and wooden
    mounting block, which showed that the adjustments of the previous day
    were all over the shop. Its quicker and totally accurate. The
    procedure was posted in the Journal a couple of years ago.

    When David Kinney and I were at Samick doing some work in January,
    the head technician showed us his dial gauge and block for setting
    the bolts in the same way. So that's two techs I know of who came up
    with the same idea independently. The third was Richard Davenport.

    Anyhow Ric, if you didn't use a dial gauge for setting the bedding
    bolts, its time.

    Regards,
    Ron O.

     >I ran into a symptom I haven't identified before.  I was bedding an
     >older Steinway D today, and made sure all three rails were good and
     >done in the right order... yet I was still getting too much hammer
     >bounce in the bass section on a hard blow.  The rest of the piano
     >was just fine... just the bass section had this problem.  Started
     >troubleshooting by first lifting the whippen up with my finger and
     >hitting the key hard to see if there was any bounce... nope..  Then
     >I lifted the hammer with a shank hook and hit the key hard... still
     >no bounce.... Then I noticed that when I lowered the shank enough
     >for the back check to make contact with the hammer tail... the
     >neighboring hammers started to bounce.  When I let the hammer go
     >into full check the full effect of neighboring bounce kicked in.
     >
     >I haven't managed to pounce out what the cure for this is.  Checking
     >distance is 15 mm... action is reasonably well regulated... drop is
     >a bit deep but letoff, dip and aftertouch amounts are all well
     >within good tolerances.
     >
     >Any advice on the matter is of course very welcome.
     >
     >Cheers
     >RicB


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