1927 Catalog Drawing vs 1929 ratchet (15 tooth)
5/8 inch drive ratchets
The 5/8 inch drive was first offered in 1923 and continued in some form into the 1970s. There is a huge gap in the catalogs and these ratchets were offered for 8 years (in the catalogs). The 3/4 inch ratchet is exactly the same. Snap on names these -– Heavy Duty – and then does not define the square size (5/8 drive). During the early period the 9/32, ½, 5/8 and 7/8 drives were the offerings. Later the 1/4, 3/8, 1/2, 3/4 were standards