Been there, done the same thing. Like mentioned above, slow and rigid as possible on a drill press. Its definitely a challenge, thats for sure. I counter sunk the hole on the piece below using an Enco single flute 60° countersink in a drill press with the piece held in a small vise...it chattered right off the bat. Since then, I got a mill and no more chattering!
![IMAG1194.jpg IMAG1194.jpg](https://www.hobby-machinist.com/data/attachments/24/24103-2877f357859560911dc835e379664e2c.jpg)
![IMAG1194.jpg IMAG1194.jpg](https://www.hobby-machinist.com/data/attachments/24/24103-2877f357859560911dc835e379664e2c.jpg)