Just a bit of trivia, B tapers are based on Morse tapers
From Wikipedia
B10 = small end of MT1 (D = 10.095 mm)
B12 = large end of MT1 (D = 12.065 mm)
B16 = small end of MT2 (D = 15.733 mm)
B18 = large end of MT2 (D = 17.780 mm)
B22 = small end of MT3 (D = 21.793 mm)
B24 = large end of MT3 (D = 23.825 mm)
From Wikipedia
B10 = small end of MT1 (D = 10.095 mm)
B12 = large end of MT1 (D = 12.065 mm)
B16 = small end of MT2 (D = 15.733 mm)
B18 = large end of MT2 (D = 17.780 mm)
B22 = small end of MT3 (D = 21.793 mm)
B24 = large end of MT3 (D = 23.825 mm)