Customer in Dayton asked me this today: the “32” is the nominal major diameter of the collet taper in millimeters per DIN 6499, and each ER collet typically offers about a 1 mm clamping range. Got any other tool naming quirks you hear from new hires or customers?
Fun trivia: ER = ‘extended range’ from the old E collets, which had about half the collapse. I still tell new hires to treat the 1 mm as marketing and keep to about 0.5 mm if they care about runout — does that match what you see on the floor?