Hi Joe...
How do you mean "contact point" Do you mean the contact that holds it down to the keybed or the point that could control in and out location?
In the holding it down to the keybed direction, its really not supposed to crank it down to the keybed. It only is supposed to keep the action frame from falling out of position when the piano is on its side. The dag is not really supposed to serve as a bedding restraint for the keyframe backrail, but often ends up providing this function. As long as you have a slip fit without too much slop vertically its fine, in my view. I bded the backrail passively to the keybed, as Chris Brown has written about.
In the in and out direction, most dags are not set up to control the in and out position of the keyframe. Cheekblocks do that, and are adjustable. Some manufacturers include a capstan in the dag for in/out positioning, but they tend to grind up the back edge of the keyframe. Steinway controls in/out with the cheekblocks. So there needs to be some slop between the back keyframe edge and the vertical interior surface of the dag, so the keyframe back edge does not jamb on the dag's vertical interior surface.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
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Original Message:
Sent: 09-21-2020 16:44
From: Joseph Burros
Subject: How to Adjust Key Frame Back Acton Rail and the Dag Block hold downs!
Hello all,
My question is, on a Steinway grand piano, do any of you have a protocol for adjusting the contact point between the four rear contact points on the keyframe and the four Dag Blocks that are inside the piano? Is this a crucial adjustment and is the workings of the action and the sound of the piano improved if there is the correct amount of contact and down force between the Dag Blocks and the back of the key frame?
How does one properly evaluate and adjust the rear key frame hold downs?
Thanks,
Joe
P.S.
I was reading the Steinway manual and it says this about adjusting the Dag Blocks to the back contact points of the key frame:
Lubricating Dag Blocks & Key Frame Contact Points
- The back rail of the keyframe is held firmly in place, with minimal friction, with the aid of the dag blocks. These are glued onto the back rail of the keybed. The dag block and keyframe-mating surface coated with graphite to ensure smooth and accurate shifting of the keyframe. Check to make sure that the dag blocks are in contact with the back rail.
- If there is a space at this contact point, glue a veneer on the back rail of the keyframe and re-apply graphite. If there is too much friction at these points, lightly sand the keyframe as needed, and re-apply the graphite.
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Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
www.fmi-newengland.com
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