National Twist Drill Co HSS 6" x 2-1/4" x 2 16-Teeth Arbor Shell Mill. National Twist Drill & Tool Co. HSS Parabolic Shell End Mill 6" x 2-1/4" x 2 Arbor. Actual Number Stamped On Tool: Detroit HS H.Parabolic 6 x 2-1/4 x 2. Unused inspected overstock as described, shown and pictured. Industry Recycles has been serving the Industrial Marketplace since 1998. With 200K Square Foot of Warehouse space in Sunny Florida, we proudly sell the toughest inventory to the toughest market in the world, AMERICAN small business. Each year, we have over 50,000 new satisfied clients, and many repeat buyers. Mention details and specifications that you believe are relevant to your buyers. Parabolic 6 x 2-1/4 x 2 Unused inspected overstock as described, shown and pictured. Henry Sep2716 HF1446 CabPadmeBin15 Modified by Kimmy 03-09-2017.