Originally Posted by feline fanatic

I usually add 1" instead of the 7/8 and trim down. I find it easier then messing around with 1/8" measurements and never have a HST come up short that way. As to why... I don't bother to strain the brain cells trying to figure out why. It works and that is why I do it. I always thought it had something to do with the pythagorean theorem but I could be wrong.