Jacobs Drill Chuck Arbor #7345D, 2MT Shank, 3/8"-24 Threaded Mount - 63-004-741 - Penn Tool Co., Inc
JT6 Jacobs Taper 6 Drill Chuck 1/2" Capacity with MT2 Morse Taper 2 Arbor & K 32 Key - Amazon.com
Jacobs Set of Two Drill Chucks with MT2 Morse Taper 2 Arbor and Keys 0 - 3/8" and 1/16" - 1/2" Capacity for Lathe Tailstock and Drill Press - Amazon.com