Threaded Shank Adapter Drill - Type "B"
page 125A
Type "B" HSS Threaded Shank Adapter Drills are for medium duty drilling in low tensile strength materials.
Threaded Shank Adapter Drill - Type "D"
page 125B
Type "D" Cobalt Threaded Shank Adapter Drills are used for heavy duty drilling in hard, tough tensile strength materials.