No Power Yamaha revisited

[Roger Jolly]

Hi Avery & Ric,
                          I have a good minds eye view, of what is going 
on, but I'm not so sure I can explain it well.   But here goes.  (Send me a 
deluxe flame suit Conrad).

If you have the bolts just touching, there is no compression force acting 
on the balance rail.  With rapid forceful playing, there is a small amount 
of bounce taking place at the balance rail, robbing the action of a lot of 
energy.  It gets dissipated within the frame.
Jack the bolts a little further down,  you start to bow the cross 
struts.  and putting some compression into the rail. , and firmly seating 
it to the bed.   At the Yamaha Technical Academy, they spend a good deal of 
time teaching you how to tune these rails in aurally.  takes more than a 
little practice to get optimum results.
The front rail is done first, by tapping on the front rail with a kind of 
45 degree blow, to the leading edge of the rail.  (You can hear better than 
the traditional method of holding a key down and thumping on the key, the 
front rail punching absorbs a lot of noise,) Then the bolts are adjusted so 
the front rail just starts to lift, then back off about 1/4 turn.  Next 
step is get all the glides bedded so the tone is the same when lifting up 
on the hammer rail, and thumping down on the balance rail.

The closest analogy I can think of,  is like string bearing across the 
bridge.  Too much bearing and a loss of tone, too little loss of tone.

Now I will crawl under my rock and smile.

Regards Roger

PS  I thought we covered the topic of hardwood and softwood rails, quite 
well in the Interactive Grand Regulation series.  Gee that was 2 years 
ago.  Tempus fugit.


At 04:03 PM 5/22/2003 -0500, you wrote:
>Hi Roger,
>
>But why won't Yamaha tell us how they do it? (See my previous post to 
>Richard.)
>
>Avery
>
>At 01:56 PM 05/22/03 -0600, you wrote:
>>Hi Ric,
>>            A very soft flexible action frame, they move a lot.  I bed 
>> these frames every time I tune a Yamaha grand.
>>With practice it only takes about 3 or 4 minutes.  The weight of the keys 
>>is more than enough to flex those frames, hence the change in dip.
>>The design is such that the frame is is supposed to flex.
>>Bin thar and bought the tee shirt.   <G>
>>
>>Regards Roger
>>
>>At 06:12 PM 5/22/2003 +0200, you wrote:
>>>Ok guys and gals...
>>>
>>>I gots to eat crow here...  I think anyways. As it turns out I managed
>>>to finnally solve the hammers bouncing all over the place thing by
>>>turning up all the bed screws so that the key frame was solidly bedded
>>>with the actuall wood of the balance rail a full 2 mm elevated over the
>>>key bed. Huge increase in power, but this also caused an increase in
>>>keydip to 10.5 mm (!) and forced a drop in blow to just above the
>>>cushions... perhaps the shanks are about 2-3 mm off. However....
>>>absolutly no bouncing of neighboring hammers any more, and that feeling
>>>of loosing power is gone.
>>>
>>>What I dont get is why the Balance Rail needs to be elevated so much.
>>>And how are we supposed to determine the proper balance rail height to
>>>begin with ? I was always told that glide bolts need to just make
>>>contact with the key bed... not to lift the whole darn middle of the key
>>>frame up.
>>>
>>>Explainations please ?
>>>
>>>RicB
>>>
>>>--
>>>Richard Brekne
>>>RPT, N.P.T.F.
>>>UiB, Bergen, Norway
>>>mailto:rbrekne@broadpark.no
>>>http://home.broadpark.no/~rbrekne/ricmain.html
>>>http://www.hf.uib.no/grieg/personer/cv_RB.html
>>>
>>>
>>>_______________________________________________
>>>pianotech list info: https://www.moypiano.com/resources/#archives
>>
>>
>>_______________________________________________
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>
>_______________________________________________
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