Make sure your z axis can pull your cutter high enough. You'd be surprised at how much z axis height you need if your'e cutting out a les paul body which is 63 mm thick + if you have a baseboard/wasteboard and the cutter needs some free space to move over the wood blank. Do your'e summs. The size of the stepper motor dictates the size of the cutter you can use. With a 6mm router bit you wouldn't need a super strong stepper. Your powersupply will also dictate the size of your stepper. My ancient old Makko M850 probably has 2nm motors and it works albeit slowly. I think 3nm should be more than enough
https://www.omc-stepperonline.com/cl...op-stepper-kit
https://www.sorotec.de/shop/CNC-Mill...lling-Kits-en/
I've bought a sorotec compact line kit quite a while ago (i have'nt found the time to put it together yet ) and they recommend 3 nm . Try and get closed loop motors if you can or even servos. I think you'll probably get more low speed torque on the closed loop(don't quote me on that ) A decent stiff machine is the most important thing with cnc. Lower powered motors mean everything is a little slower, but if the machine is rigid you'll get a good cut finish. Sorotec has some good spiral wood cutter that are not to expensive. Don't think you'll be knocking out guitars like Fender!! there's quite a learning curve. It is nice to watch a router cut the fret slots, although it might be quicker by hand.
Cheers Andrew