Rails to bearings to carriage to... drive system?

[Losos]

I feel like an idiot... I'm confused on what seems to be the most essential component of a cnc machine: connecting the drive system to the part you want to move! What are the steps and components involved in connecting the carriage to the drive system? (explanations specific to screw driven, belt driven, R&P, ... and/or all the other drive systems out there would be great)

[Hobbiest]

With a screw drive, your carriage would have a nut whose threads match the leadscrew mounted to it. Rack and Pinion would have a pinion gear attached to the motor, on the carriage, with a gear rack fixed to the axis. In a belt config, you would have a fixed motor, with an idler at the extreme opposite end of the axis, the belt would then be attached to the carriage. There are many other ways to do all of this (i.e. fixed lead screw and rotating nut), but these are the most basic.

[Losos]

Thanks Hobbiest. I found a pdf that has a good diagram of a simple belt system -- http://www.idcmotion.com/pdf/9002.pdf . You're right, doesn't look like there is much to it. Are there any good online stores that sell prefabed belt-mountable carriages? It seems like every belt system I have seen the designer has machined the mounting pieces on their own.