Carpenter pencil, cut to a knife blade of sorts, fine tuned on the concrete floor. It is just too simple. Don't have to search for bamboo or keep an ink pot at hand. I would have it all over the place and upside down and all over my face. I can only imaging it being like anti-seize while doing mechanic work. Even after a day of layout my hands are covered in graphite.

I often mark on my tape, with fine tipped markers of various colors and or pencil, given lengths, not paying attention to the fraction but making a story pole out of my tape. No 86--68 mistakes, which I am prone to. Short lengths I will use my dividers, again no chance of miss reading fraction or mixing numbers.

I am finding more and more I mark an X at the outside ends of my mortices and tenons. Center line the mortice for the boring machine bits with proper spacing and sometime 1/8th pilot hole an inch or so deep. A little extra time but makes the setting of the machine a cinch, no over bores.

I scribble numbers on the yellow case of my tape all the time, stays long enough to get to the saw and will rub off. It should have a special pad for such a purpose.