Changer info request...

[Allan]

Is it possible that someone can give me an idea of the angular rotation that a changer finger goes through when a)raising, and b)lowering, a string by a whole tone?
I am looking for the worst case situation here. I believe that the change is greater in the case of a plain string as opposed to a wound string.
In common with some others here, I am trying to get as far along the design process road as I can, before I start putting tool to metal, so this information would help me enormously as regards which way to go.

Thank in advance...
Allan.....

[burt]

I can tell you how many degrees my 4th string (0.014 plain) moves through to get a full tone raise (just over 7 degrees) and a half tone lower (just over 3 degrees), so we can extrapolate this info to arrive at an educated guess of at least 14 degrees of rotation to go from D to F# (24 inch scale length, normal keyhead, 3/4 inch diameter changer finger).

[Georg]

I haven't measured angle, but my 3d w/half-tone raise need a larger change than my 4th w/full-tone raise, so the angle is larger. That I also lower my 3d a full-tone may not matter for most players/builders, but the angle is fairly large for that lower on 3d.

As experienced by most who switch from plain to wound 6th string, the wound string needs a larger change-angle than the plain one. That's why a wound 6th reduces audible body-drop.

[Dave-M]

For those who may not know, the angle may be determined from a slope of two right angle measurements.

Locate calc.exe in windows\system32, or wherever it is on your computer, and put a shortcut on your desktop for quick access.

Using the scientific view on the calculator, make sure degrees and decimal (Dec) boxes are checked.

To calculate the angle in degrees of the slope of two right angle measurements of a finger component, divide the horizontal displacement by the vertical length of the moving part. Then click inverse box and tangent. The approximate degrees rotation for small angles will be in the result window.

For more accuracy, instead of the component length, use its length minus vertical displacement, which is negligible for small rotations.

[Allan]

I can tell you how many degrees my 4th string (0.014 plain) moves through to get a full tone raise (just over 7 degrees) and a half tone lower (just over 3 degrees), so we can extrapolate this info to arrive at an educated guess of at least 14 degrees of rotation to go from D to F# (24 inch scale length, normal keyhead, 3/4 inch diameter changer finger).

Good stuff Burt, thanks. That's all I need for now...