what is downbearing?

[JIMRPT@aol.com]

In a message dated 20/02/04 11:38:36 AM, dgilmore@kcmpi.net writes:

<< A dip angle of as much as 5 degrees will result in a downbearing force of 
T * sin 5.  Sin 5 is about .0872, so the downbearing force would only be about 
9% of the string tension.  For a string tension of 150 lbs this would only 
amount to about thirteen pounds. >>

Hmm using that 5 degrees and an old Knabe I am rebuilding currently, which 
has 223 individual tuning pins,...would give us (150 lbs X 223)= 3,345 lbs of 
downbearing pressure....no wonder there is compression set/damage!! :-)
 I think that in general the total pressure from down bearing amounts to much 
less than this...say in the nature of 3 to 5 lbs and range totals  more in 
the neighborhood  of 670/1115 lbs. But I certainly am open to changing my 
viewpoint. We need to keep in mind that it takes more and more lbs of pressure as 
the degree of displacement rises...in other words downbearing is geometrically 
progressive...isn't it??
Jim Bryant (FL)