A router that size to cut wood should be pretty doable in mdf with steel pipe. It's usually 1/8" thick or less wood routing and most people buy the guitar neck already done. Especially if you only build a router, no neck making with this of course.
I'd recomment you make it a mill instead as you can cut the corner parts, neck with fretboards lines, inserts. Well, you may at least make provision for it in your design. Check the free cnc plans. JGRO's design is pretty all right as a starter.
Concerning the size you chose, don't forget that the guitar sides are much longer than the top as they curve and go around the butt. If you want to cut those as well you will have to make the table much longer. I would take a guitar plan and double check this... Kind of unfold the side part and check the lenght
It's up to you, but if you get into this, in not time you'll be wanting faster, biger, stronger...
Take your time to build it strong and right, you'll be glad you did'nt skimp on the details...
I'd love to do guitars... But what I like most is to make em scream...
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