Hi.
I'm new-ish around here (I've lurked for a few months).

I'd always wanted to build a CNC machine to control a drill or router.
So this last winter I did.

It's made from old kitchen worktops - 38mm melamine chipboard, bolted together with home-made dowel-screws.
Fixed Y gantry with a moving X bed.
Linear bearings made from pairs of opposed ball-bearing drawer runners.
M6 threaded rod, with home-made delrin nuts, and skate-board bearings each end.
nema23 motors connected with garden hose and jubilee clips.
diycnc(crh electronics) system 3+ driver board.
cheap 24v 6.5A supply.
bosch hobby router / proxxon drill.
Working area of 420mmx420mmx230mm xyz.

My intial aim was very modest - to get accuracy of about 0.1mm to help me cut PCBs into weird shapes, engrave wooden signs etc. Oh, and my budget was small... hence no ground ballscrews or fancy bearings anywhere.

It's worked better than I ever hoped. It's happy drilling holes in PCB, cutting out PCB shapes, routing MDF, routing wood...
It easily gets 0.1mm repeatability, and it cuts MDF/wood at 300mm per min like butter. (Okay, shallow cuts of 2mm, but I'm learning...)

It's happy doing 600mm per min rapids, which is fast enough for me.

The Z axis is the weak point - the drawer runners can't be mounted opposed - so it's a little wobbly. I'm currently wondering whether to make a new Z using right-angle aluminium and skate bearings.

Oh, and I'll be trying to wire up an SSR in the next few weeks so I can turn off the drill/router and vacuum cleaner at the end of a program.

Currently running on Mach3 freebie (500 lines of gcode), but I want to try linux/emc2 fairly soon.

Enough wittering.
Cheers,

Keith.