Square Hole Drill Bit Adapter for Easy Installation and Disassembly - Mortising Attachment for Drill Press, Mortise Machine Power Tool Accessory for Drill Machines - Walmart.com
Mortising on the Drill Press | Popular Woodworking
DELTA Template in the Drill Parts & Attachments department at Lowes.com
Mortising Attachment Kit at Grizzly.com
DIY Mortising Attachment for Your Drill Press - $20 smackers-ish - YouTube