Hello,

The substance of the markings is interesting enough, be it lead of times gone by, graphite mixed with wax and clay, rabbit skin ink or a scratch into the wood's surface. Also not to be forgotten is the mechanics of your tool. For example my bamboo stick is shaped to suit my preference even though I stick to the standard form in general, being left handed, I make it accordingly, with a knife edge, single beveled, relieved at the back corner. The flattened backside means I align the square exactly at the measured indications, no accommodating an offset to account for pencil thickness or bevel angle, which as I pointed out change from one side of the line to the other when using pencil.

And what's more the mechanics of an engineers pencil is poorly suited for the work because the lead is gripped in the jaw at only one concentrated point where it is bound to snap off as has happened to Will T.

Greetings,

Don Wagstaff