Originally Posted by
StraightRazorDave
The first equation is correct, but there is a small flaw in the second equation. You are correct in saying the width of the spine changes giving you the extra term to be added to B, but it shouldn't be 2*tape_thickness since you are only considering half the angle in this triangle, thus only 1*tape_thickness, the thickness of the other half of the tape is already accounted for in the 2* in the beginning of the equation before the arcsin term. Also, A in the second equation is not the same A as in the first one. When you add tape, you are not only increasing the thickness of the spine, but also the distance (the hypotenuse "A") from the edge of the bevel to the spine.