Rockcliff Machines Inc.
Build Your Own CNC Router Machine
Solsylva.com
Joescnc.com
Hobby CNC
John C Kleinbauer’s Unique Plans for Hobbyists
JGRO Router Plans
DIYLILCNC
MYDIYCNC
MechMate
Momus CNC
BootstrapCNC (My Plans)
Not plans, but an interesting read: LumberJocks CNC Router Thread