[CAUT] Una chorda shift "click"

[Paul T Williams]

Doug (and all)

I think it may be indeed a problem with the shift lever and not the 
spring.  I'll probably need to do the maple insert.  I rounded the top of 
the lever as you suggested and the sound was dimished some, but more 
investigating with all your suggestions should resolve the 
problem...unless it doesn't ;>)

Have a great Thanksgiving all!

Paul




From:
dew2 at u.washington.edu
To:
caut at ptg.org
Date:
11/24/2009 05:50 PM
Subject:
Re: [CAUT] Una chorda shift "click"



In my experience, the shift slot/shift lever interaction is the most 
likely source of noise on slow shifting. Don is right on with the careful 
examination of the glue joints--I've had several pianos with this problem. 
The ends of the hard maple insert on which the lever bears must be either 
firmly glued or completely free. (The main glue joint is the long side 
opposite the lever.)

It has been common, in some eras, for the shift lever to be less than 
ideally ground where it contacts the keyframe. The concave grind will 
quickly damage the wood of the slot. I've had good results correcting this 
with a file, making the lever slightly rounded front (of piano) to back, 
and perfectly straight vertically. I do usually round the top very 
slightly, just enough not to have a sharp corner.

The problem is that once the shift slot begins to deteriorate, it will 
persist in making noise until the hardwood insert is replaced or at least 
refaced with new wood. As in cut out a piece of the maple and glue in 
another. The location of the slot is very important: I've been operating 
under the assumption that both slot and lever should be perfectly vertical 
and just in contact at rest. I'll mention that I prefer hard maple, but 
Ken Sloane (Oberlin) favors sugar pine. ?? I have also used pieces of the 
spacers from hammershank sets.  Seems to me that something very tough and 
naturally self-lubricating might be even better? Anyone ever try lignum 
vitae?

It is possible to shift the action without engaging the lever, by pulling 
hard (both hands!) or prying (carefully here!) on the bass end. If it's 
the spring, it will still make noise. If no noise, then get under the 
piano and work the lever with your hand--it will probably make noise, thus 
indicating the lever/slot interaction, or the hardwood insert/keyframe 
joint as the source.

Have fun!

Doug Wood

On Tue, 24 Nov 2009, Don Mannino wrote:

> Ah, another mystery.  Keep in mind that noises travel a bit in the 
keybed
> itself, so sometimes the location is misleading.
>  
> - Check for a loose balance rail glide bolt
> - Tighten action stack screws
> - Check keyframe glue joints on the right side of the action. I have had
> this kind of noise with glue joints which have become loose.
> - Remove, lube / rebush (if needed) una corda lever pivots. Check for
> rubbing or interference.
> - Remove spring and check for something fallen behind it. Make sure
> screws tighten well when it's put back.
> - Look at keyframe where una corda is pushing on it.  Check for split
> /chipped wood or other damage.
> - McLube 444 on top of una corda lever, side of keyframe, and on return
> spring.
>  
> Don Mannino
> -----Original Message-----
> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
> Paul T Williams
> Sent: Tuesday, November 24, 2009 2:20 PM
> To: CAUTlist
> Subject: [CAUT] Una chorda shift "click"
> 
> Hi all,
> 
> Our Steinway D in one of our halls has a weird clicking or groaning
> noise with the unacorda shift movement.  It makes a "click" or
> something like it when pushing the pedal down.  It is minimal when
> pushing quickly, but is very noticable on a slow push.  It's also even
> more noticable on pushing and releasing the pedal.
> 
> I sanded and lubed the right side of the key-frame, and also polished
> the return spring, but it only went away slightly. It sounds like that
> is where the sound is occurring.  The lyre action is not where it's
> happening, so where might I look next?
> 
> Thanks
> Paul
> 
> 
>


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