Chagrin:
You're describing a "mortising bit" (just the bit) or "mortiser" (full machine). Any woodworking store would have them and the machines are still widely sold. To use a mortising bit with a drill press you'd need a "mortising attachment" (~$100).
Thanks for the mortiser word. (My mother tongue is not English)
A google search and readup led me to this page Make: DIY Projects and Ideas for Makers |
Reminded me that I have a nibler tool and a unibit which seem a good combination for small series (1 or 2 pieces)
Best regards
Jantje