This standard specifies the shapes and dimensions of Morse taper sleeps (hereinafter referred to as sleeps) and Morse taper shank sockets (hereinafter referred to as sockets).
JIS B 6163:1998 history
1998JIS B 6163:1998 Reduction sleeves and extension sockets for tools with Morse taper shanks -- Dimensions
1974JIS B 6163:1974 Reduction sleeves and extension sockets for tools with morse taper shank