I have seen on some CNC routers a cable guide that is a rectangular
assemblage of hinged segments that resemble tank treads. It reduces tight
flexing while keeping the control cables out of the way. What do you call
them and where do I get some?


It is commonly known as flexible cable track or flexible wire duct. Some
links are below.

http://www.lappcanada.com/onlinecatalog-track.htm

http://tinyurl.com/d7a28

http://www.kabelschlepp.com/microtrak.htm

HTH

--
Larry Green