In an earlier post, I showed that pencil companies have distinctive ways of expressing a 2½ lead hardness. They also have come up with unusual hardnesses and corresponding lead numbers —
The Templar’s 1-5/8 is “Exclusive with Reliance” —
Theoretically, that would be just a tad harder than the Berol Mirado’s 1½.
In fact, Eagle (the forerunner of Berol) had a 1½ , and also a 3½, back in the 1800’s —
The Eagle card also provides details of an old B/H system that was used for high-quality art and drafting pencils. They squeezed an FHB between HB and F.
F is not an unusual grade, even for regular pencils, but only Eberhard Faber put it equal to 2-3/8, as far as I know. According to this Berol Black Warrior, F (literally, F2½) is equal to 2½: