[CAUT] strange rib damage

Fri Dec 10 08:50:49 MST 2010

That would be correct.  It depends, of course, on how you set bearing and
that may depend on the type of board and/or its condition.  I often try and
set bearing at the low end of the bass bridge at near zero with only
slightly more pressure at the upper end of the bass bridge.  Some set even
more bearing at the upper end of the treble bridge than I have indicated.
This is an average setting for me on the new boards that I'm doing (rib
crowned with minimal compression) and I find it unnecessary, even
counterproductive, to load the board more than this.  In practice, at the
very top of the treble bridge (last half of the upper section)  I actually
back off the bearing some down to more like 1 degree.  The board is usually
stiff enough up there without trying to achieve it by adding load and more
problems come from too much stiffness or a restricting movement (jangles)
than the opposite, I find.  

David Love

www.davidlovepianos.com

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Laurence Libin
Sent: Friday, December 10, 2010 7:23 AM
To: caut at ptg.org
Subject: Re: [CAUT] strange rib damage

Just to be sure I'm interpreting this correctly, each string of trichord
Note 88 exerts a downbearing of 4.423 lbs (1/3 of 13.27 lbs), roughly 3.6
times more pressure than the single string of Note 1, right? And pressure is
not evenly distributed across the bridge and soundboard but much more
heavily loaded at the treble.

Laurence Libin  

----- Original Message ----- 

From: David Love <mailto:davidlovepianos at comcast.net>  

To: caut at ptg.org 

Sent: Friday, December 10, 2010 9:47 AM

Subject: Re: [CAUT] strange rib damage

Here's a typical Steinway B scale and resulting lbs.  This totals out to 694
lbs.  The lbs on each note takes into consideration the number of unisons.
Using an average setting of 1 degree for every string would produce a total
of 698 lbs.  HTML probably helps to keep the chart organized.

Note# / bearing deg/ lbs

1

0.25

1.22

2

0.25

1.21

3

0.25

1.19

4

0.25

1.19

5

0.25

1.16

6

0.25

1.15

7

0.25

1.11

8

0.25

1.11

9

0.25

1.78

10

0.25

1.74

11

0.5

3.43

12

0.5

3.41

13

0.5

3.36

14

0.5

3.31

15

0.5

3.24

16

0.5

3.20

17

0.5

3.19

18

0.5

3.13

19

0.5

3.04

20

0.5

2.99

21

0.75

4.99

22

0.75

5.29

23

0.75

5.41

24

0.75

5.74

25

0.75

5.85

26

0.75

6.28

27

0.75

6.32

28

0.75

6.37

29

0.75

6.62

30

0.75

6.49

31

0.75

6.65

32

0.75

6.44

33

0.75

6.53

34

0.75

6.56

35

0.75

6.54

36

0.75

6.55

37

0.75

6.52

38

0.75

6.55

39

1

8.84

40

1

8.35

41

1

8.43

42

1

8.54

43

1

8.57

44

1

8.55

45

1

8.67

46

1

8.60

47

1

8.65

48

1

8.33

49

1

8.45

50

1

8.47

51

1

8.73

52

1

8.45

53

1

8.31

54

1

8.49

55

1

8.63

56

1

8.72

57

1

8.77

58

1

8.90

59

1

8.72

60

1

8.84

61

1

8.84

62

1

8.77

63

1

8.81

64

1

8.89

65

1.5

13.23

66

1.5

13.06

67

1.5

13.12

68

1.5

13.26

69

1.5

12.79

70

1.5

12.94

71

1.5

13.09

72

1.5

13.24

73

1.5

13.40

74

1.5

13.55

75

1.5

12.92

76

1.5

13.07

77

1.5

13.22

78

1.5

13.38

79

1.5

12.73

80

1.5

12.88

81

1.5

13.03

82

1.5

13.18

83

1.5

12.51

84

1.5

12.66

85

1.5

12.81

86

1.5

12.96

87

1.5

13.11

88

1.5

13.27

David Love

www.davidlovepianos.com

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