Julia wrote
I attended roger Jolly's voicing class at MARC. He spoke about "cupped" shape hammers and how the cupping occurs as a result of the cutter which cuts the whole hammer "brick"< (don't know if thats the right term) into 88 hammers. As I understand him, the cupping is an indicator that each individual hammer has less stress/tension at its sides actually because the cutting relieves the stress when they go into 88 separate pieces, thereby the sides have less stress and the center has more. I understand this is what produces the cup .
Hi Julia--You have described Rogers method as I understand and have used it. There is less is some slight loss of tension at the edges of the hammers as they are cut apart. Remember thought how much loss is dependent on how well the felt is interlocked and that has much do with the skill of the felt makers.
The cup line density can be utilized by this single large needle method. It seems to increase spring strength in the entire hammer supporting the top and utilizing the shoulder as a deep spring.
Sustain and volume are the result. Like any method there is a point of diminishing returns so it is important to listen when the improvement stops and it is a thing one learns the feel of.
He further suggests a single needle penetrated all the way to the core, directly along the center line of the hammer, 2 stitches or so, back around the way lower shoulder, say 3 and 4 o'clock, to reduce the stress which allviates the cup. (Roger if you see this, correct me if my understanding of this is flawed)
If the cup is removed by "facing them up" at the factory, doesn't this mask the reality that there is still the inner, tension through the center and the sides have less tension? Wouldn't it "disguise" the hammer as not needing "cup relief" needling, when it really does?
The initial voicing will tell you this as well as some exploratory needling hammers/notes that need tonal blending or improvement. Also some hammer sets by nature of the felt used or the pressing method employed will demonstrate more or less of this. Many hammers makers face/sand their hammer sets before being boxed and sent.
If I have learned one thing about hammers and technicians is that they want them to look perfectly symmetrical and smooth.
That said, Cosmetics has a place but tonal potential in my view is more important. ie I have seen many slightly asymmetrical hammers in many pianos or with slightly asymmetrical under felt that had a fine sound. ie many old Steinways and others.
Actually this is can be a sign of efforts on the hammer makers part to reduce pre creasing the felt which is good but makes it more difficult to get the under and top felt aligned as it is going into the press and to much pre-creasing or pre-bending/folding of the felt so the under felt can lay in that trough reduces resilience in the final product.
Too much pre-creasing too much heat helps the hammer felt conform to the hammer form caul but at some point the result is something that resembles an item that was made by plastic injection molding instead of organic material.
Dale
Julia
Reading, PA
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