It’s true. I allowed myself ten minutes per sketch and then it was pen down. Sketching is my way of looking without spectating. I want to see the twists, flexes and locks that take place to the hand and whereas you can see that with a photo, often photos are staged and they quite often don’t reflect the truth of working so much as the imagined. Read the influence of watching or being watched in an experiment that watching has. There are lines in the hand when it is performing a task that expresses information to the observer but especially is this so when nothing is frozen as in a photograph but by the brains ability to register images as memory. Drawing them means that we draw (no pun intended or maybe it is) both with the instrument and the right parts of the brain using both in union as we draw. Because of this we may compare a sketch to a photograph but the brain image is more as a video or, perhaps nearer still, a flipper book. We lock onto the distortions of the hand to make a clearer representation in our drawings.
My drawing of planing for bevels or chamfers (top) on end grain corners shows the two angles of presentation,and then the hand positions I use to get the optimum cut from my plane. For the two sketches here I allowed myself 10 minutes. This time limit makes me work fast and rely on my brain. The mirror is of course the opposite so I must also interpret myself as a right hand dominant worker. It’s interesting to use a mirror to work from but then you must feel for the intonation you use when you are actually performing the the reality of the task and not ‘acting‘ the task.