About Sherline Mill collets
Sherline milling collets are designed to be used with the Morse #1 internal taper that is standard on both the Sherline lathe and vertical mill. Because of the shallow angle of the Morse #1 taper when the drawbolt is tightened, a greater clamping force can be applied when compared to the clamping pressure of WW collets. Therefore, we recommend the use of these milling collets for holding miniature size end mills (3/16″ or 1/4″ shank), #1 and smaller center drills, or Dremel® bits (1/8″ shank), and assorted other cutters.
Cutting tools held by these collets must have a shank size within .001″ of the manufactured size. Because of the shallow taper angle, these collets will not loosen from the spindle without backing the drawbolt off a couple of revolutions and tapping the drawbolt to free the collet.
You need to make sure that your Tommy bar is not too far into the spindle hole if you use it to tighten the collet draw bolt, or you will damage the taper area of the collet. The red arrow in the image below shows the type of damage that can occur.
Always wear safety glasses when operating machine tools.