oritteropo says... The inch came from the yt description... strangely the millimetre came from Jalopnik, their writers do seem quite civilised. I've tried to explain to my children that an inch is 25.4mm, and made exactly 25.4mm around the 2nd world war, but they don't understand why anyone would want to use such a strange and odd measure. I didn't even try to explain the barleycorns. Oh yeah, and I liked the vid too. Payback said: Hey, Love that motorcycle engine sanding video. I wonder when the first grammar nazi will point out you said "an inch at a time" in the description. ... oh shit.