Don't feel like the only idiot in town, I can do math, algebra, and a little trig. I I can figure valve timing, port timing, cam timing, ignition timing, can time the sprockets on a twelve roe planter to place different size seed from 1/2" to 5" apart or even drop 5 in one hill. I can time a haybaler knotter to try string and the needles to clear the plunger perfectly. BUT I have asked at least 15 different gun smiths to describe how to time a bolt or tell me how to know if it needs to be timed and I have gotten 15 different answers. AND these are good smiths, capable of building top grade rifles. I'm like you, I would like to have a picture in my head of exactly what makes it timed or out of time!