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I thought about this alot last night about how to explain it - I see where Paul and Todd are coming from, thinking that if the string height is 1/2 inch, no matter what the bridge saddle config is, then the torque is the same. But, do you agree that the down pressure on the saddle changes with break angle, given the string height stays the same ??? Then the torques has to change also. Why is that - because the force on the saddle is not directly down on the top - for that to be true the string would have to break down at the top at the same angle it approaches the saddle. But it doesnt do that ever. The string creates forces on the saddle as shown way back in those force vector drawings. The greater the angle the more force you get on the saddle. Rotational torque is a function of force and distance from the rotational centre, which is essentially the physical centre of the bridge. If you move the force away from the centre, the same force produces more torque - think of a wrench or socket drive - same force further away creates more torque. So, by increasing the break angle, we create more force on the saddle which is closer to the leading edge of the bridge, and thus the rotational torque will have to increase.
Paul mentioned that there are two torques, one of the saddle trying to break the slot, the other on the top - well if the saddle slot doesnt break, than that force is being applied to the top - it has to go somewhere.
There are actually two torques applied - one where the string breaks off the bridge pin hole, the other at the saddle. The two forces (not torques) may be the same total for two different saddle/bridge configs (again assuming the string height stays constant), but the position and value of each force can change, and since they occur at different distances form the rotational centre, the torque applied will be different in each case.
Todd - lets take your example of the staple type saddle with some sort of eye bolts holding the ball ends. You are correct, the torque has not reversed - why - because the direction of pull is still the same about the centre of rotation, and thus the direction of rotational torque is the same. Now want to change the torque value WITHOUT changing the tension or saddle config - thats too easy - make the eye bolts longer and the torque will go up - its a simple lever at at work - same force, longer distance - if this werent true longer wrenches wouldnt work at all.
The bottom line in my mind is if you beleive that the downforce on the saddle can be changed by changing break angle, then the torque has to change with it - you are moving the position of the force, and torque is forcexdistance.
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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"
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