Here are two places to get diamond core drills:
195 West Olentangy St.
P.O. Box 389
Powell, Ohio 43065
I don’t know if they have a website and I haven’t dealt with
them lately, but the core drill they sent me is just fine. Also
Kingsly North, Inc.
910 Brown Street
P.O. Box 216
Norway, Michigan 49870
I hope you get what you want.
Len Carlson in Arlington, Virginia