I prefer Dixon 2.5's, mechanical leads break under my use, and harder pencils leave too feint a line for my liking. I have a flat-sided (More reliably rides the chosen straitedge) reconfigured carving tool which takes and holds a fine point for Awl-line layout when circumstance or the client's wishes demand.
Thane - I'm not sure it is possible to suggest pencil lines are or ever will be a way to date frames now or in the future. I've occasionally found total pencil layout on earlier frames. Pencil manufacture Stateside began in 1812 in response to the then ongoing blockade, and the stop in flow of British made pencils - This obviously to fill an existing demand. And the oldest existing example of any type is said to be a 17th Century Carpenters Pencil.
Sorry about the aside - Pencils as used by Carpenter's are an area of revolving focus again at the moment > I'm finding very fine line Red Grease Pencil layout on the current project frame which dates to the first few years of Square Rule. Interestingly they used the red lines to highlight the difference between those and adjacent lines - Lines struck at theoretical depth of Housing as opposed to the Awl struck Shoulder / Cut line to go into that Housing, And lines struck and carried around to delineate the Relish for a mortise for a Boxed Tenons as opposed to those which described the end cut and the Housing which are awl struck - If anyone here has researched Grease Pencils, their use in layout or for Carpenters Marks, give me a Shout.
