Pencils often feature lead property indicators in form of an adjustable component that serves as a memory aid in remembering the specifications of the used lead like usually hardness, very rarely color.
Have you seen the one on the KIN Select-O-Matic 5617? Its adjustable ‘Eye-Cue’ indicator for 16 degrees of lead hardness was patented in 1953! Hard to set as it had separate movable wheels for 2 rows of numbers and letters.
I guess the Platinum Pro-Use 1500 falls under this group as well? I love its uniqueness but in actual use, it’s not easy to read. I keep squinting to locate the tiny ‘>’.
A variation of 2 & 3 which somehow incorporates the “Eye-Cue” can be found in early F-C models (e.g. the A.W. Faber-Castell Locktite 9800-SG); a cylindrical band with a small window to show the lead hardness wraps around the rear end of the barrel, but the window occupies just one half of the height of the band, whereas on the barrel there are two rows of lead hardness, divided into columns. This means that, by flipping the metal band in the “upper” or “lower” position, and rotating the flange, it is possible to select twice the number of different, possible lead species.
(All the variations people add here will be added later to the post, so future people hopefully can have a nice summary. Thanks for all contributions! I haven’t seen a list of indicators anywhere yet)
I am sorry, I probably misinterpreted your definition of Type 3, but from the picture seemed to me that all grades needed to be on the same facet of the barrel, not around the upper end of the barrel, whence my proposal. I agree that the Tel-a-Grade and your #3 are quite close to one another.
