I bought this set and the shank size is just under 3.2 mm. An 1/8th in. collet is perfect.
You can identify the collet size by the rings at the base.
collet: 0 rings = 1/8 in., 3 rings = 3/32 in., 2 rings = 1/16 in., 1 ring = 1/32 in.
Hope that helps...
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