Keyframe Bedding

[erwinspiano at aol.com]

? Hey Ed
? Great post. I hate it when I find out someone else has been so clever for so long. grin
? Yesterday I went thru this entire procedure on our newish Strwy D at the arts center. The piano has been in service a year or so & it was set up very well. Over the course of the years use I tweaked the casptans to restore the hammer line & turned ?the bolts up a bit to quickly rectify a bit of level & a larger lack of after touch. 
?? I am currently performing a major service in which I'm Filing the hammers to reduce balance weight( from 45 ish ) to 40 ish)?& reppinning approx 35 hammer centers. ( no friction & wobbly) plus re reg. After filing the hammers & reinstalling the action the piano sounds? a good deal more lively,of course
? SO off come the keys?& start bedding the frame.?Action is off. A few select keys are left in as visual aids.?The glides are not touching at this point by 1/2 a turn. SO with blocks in & tight I set the glides so they just touched. Loosened the block screws & the frame is touching every where along the front but I'm getting some slight slap on the back rail. ?The dags do not hold down the back, for the person who inquired. 
?? At this point with bedding bolts just touching I turned the bolts enough o raise my sample keys .020. I check & recheck the fit by gently pulling up on the keypins closest the glide location. Now when I check the front rail fit? with the block screws loosened the front rail is just lightly tapping on each end.?
? I see this as a way to mitigate slight changes from season to season.? A safety feature. It's not alot but it can be very beneficial. NOW the stack is?installed.
? Oh yeah ?& what it did for the sound was enormous.? It was the perfect A-B comparison. One caveat though is, that the back rail has a .050 upward bow at rest with the action screwed on?and doesn't touch the keybed in a large portion of the high tenor treble. I hear no slap?yet. ?I've not had to rectify this condition before. 
? Your post was timely because?the bow?is worse with the action screwed on. Laying a straight edge across the keybed in the back only showed a slight downward bow.? Not good either..? I am Open for suggestions of brilliant ones. I'll check the possibility of shimiing the stack.
? Resetting the bolts?in this manner restored the level to where only a few need punchings and remedied a more serious key travel/dip/aftertouch issue. I am however concerned for the long term backrail issues.
? Off to Jury duty....oh boy...oh boy
? Dale





Dale  writes:

<< ?I like to set the keybed/keyframe contact?with keys off & action 
screwed?to frame (as per Yamaha)?so I can really understand the unloaded 
strength of 
the keyframe I am working with. >>

Greetings, 
   I think I get better results when I bed the keyframe alone, then set the 
action on it and shim any feet that are not on the cleats. This precludes any 
internal flex, and I believe,  can make the action bedding less climate 
sensitive, ie, if there is a gap between the action and its footing, screwing 
them 
together creates a stress between the wood and the metal, in effect, a spring.  
The metal is not going to fatigue so the wood will constantly work with 
changes in humidity.   
    I have done it this way many times (going on 25 years of watching lots of 
my rebuilds), and I see stable results at the school between seasons .  It is 
more labor intensive, but, I have found that long term returns make it a good 
investment. 
Regards,  



Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html
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