Setting the Bearing
By Larry Fisher
> From: Joseph Hutter <hutter@cardion.com>
>
>
> Having restored several pianos, one procedure has always perplexed me; that
> is how to set the bearing. Not the method, but at what point should the
> bearing be set to which will provide the absolute optimum tonal quality.
>
> Is there anyone out there which could provide some further insight based on
> their own experiences?
>
> Joe
>
Well Joe, I've been told a number of things regarding this subject and none of it involves critical measurements. Perhaps a few basic rules of thumb can shed some light on the subject for you. One old timer shared with me the dime in the treble and nickel in the bass method. This is a pretty good rule of thumb on new soundboards, or soundboards that are in really good shape and have very little mileage on them. The older the soundboard, the more you'll want to minimize the downbearing to reduce the stress on the aging strength and cell structure of the wood. I've had some experience with downbearing over the years and have found it to be a subject that almost always stirs up the intellect in rebuilders. One excellent example of being gentle with an old soundboard came up in the restringing of a 1885 round legged 5' grand made in Germany. Before the job was started the piano had a very thin nasally sound, no carrying power and was generally pathetic to listen to. I figured that was the way the beast was going to sound when I was done, and made sure the customer was aware of the gambles involved when working with something that old. When I checked the bearing, I found it to be very excessive in the treble, as much as 1/8 inch too much. To cure this, I put some brass rod near the hitch pins when I restrung the piano. This put the downbearing at a very minimal amount, say about 1mm or less. I hoped that any humidity changes wouldn't affect the tone that much. Also, I've seen some pianos that have negative downbearing in places, and still sound fine, so relying on all that, I strung it up being real sensitive about how much downbearing I was providing, and concentrated on reducing overall load on the old soundboard. The results were fantastic. Amazing sound, and just a 5' grand. The customer was very pleased and I've been tuning this piano for her now for that last three years with no noticeable loss of tone.
Lar
Larry Fisher, Metro Portland, Or.
Factory Preferred Installer for PianoDisc Products
phone 360-256-2999 or Email larryf@pacifier.com
live life with variety and stare adversity in the eye! |
(Message sent Sun 7 Jan 1996, 06:36:54 GMT, from time zone GMT-0800.) |
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