SELECT MIN("Morse Taper number") FROM table_72789 WHERE "Taper" = '1:20.047'
Name the least morse taper number when taper is 1:20.047
CREATE TABLE table_72789 (
    "Morse Taper number" real,
    "Taper" text,
    "A" text,
    "B (max)" text,
    "C (max)" text,
    "D (max)" text,
    "E (max)" text,
    "F" real,
    "G" text,
    "H" text,
    "J" text,
    "K" text
)