I just checked mine. I marked it with a pencil and counted ¼ of the way around then multiplied by 4 8 counts x 4 = 32
I tried it another way. 3.5 mm in diameter x Pi = 10.995 mm. / 32 =0.34mm spacing per tooth. Checked with my vernier calipers…. Yep. Measured at just a hair below 0.35mm.