I'm just curious why measuring along the side is considered "not accurate" or cheating yourself in someway? For those of us with a strong upward "U" curve it's difficult to accurately measure on top. When I measure honestly along the side with a ruler I'm close to 8" but when I'm on top I'm closer 7.5"...unless I use a tape measure where I press it down all along the top of the shaft, I'm losing some length along the top with a hard ruler...not that you can ever really get an exact measurement anyway, I was just wondering why this is.