In the late 1930’s large wooden hooks started appearing to be used in rug making. The nine inch hooks were given the number sizes 10, 11, 13, 15 and 16 ─ no letters. When these were re-introduced in the late 1980’s the numbers had letters added so that J=10, L=11, M=13, N=15.
Size N and Q hooks began to show up in the mid 1970’s in product lines of the major hook manufactures. The Bates’ Jiffy hooks in sizes Q (15) and S (17) appeared in the late 1970’s.
Also in the late 1970’s the Handy Hook was introduced in sizes K, N, & Q and re-introduced in the early 1990’s.
Crochet hook sizes L, N, Q & S appear in the early 1980’s and the P (16) hook makes it debut. Q changes to a 19 but the millimeter size is given as 16 millimeter. Size S hook changes to 35 or 19 millimeter. The S hook was reintroduced in the early 2000’s as a “Speed Hook” by Lion Brand.
As you can see, the P and Q as well as the L, M, and N sizes fluctuated. Now, the Craft Yarn Council has standardized the sizes in millimeters as well as the letters/numbers. The following chart from the Craft Yarn Council shows the current hook size information.
