I've tried milling a few boards with my CNC machines just for fun. Using scrap copper boards. In all of them, the precision required for a clean trace was not there. Either the table was not square, the track not straight, or something. When having to control depth to 0.001" of an inch, having a straight and level system is critical. Even positioning the bit manually introduces too much error. The solution is AutoLevelling. While I still have a way to go on quality construction, here is a video showing how the AutoLevelling enhancement to a great Eagle add on called pcb-gcode works. Enjoy!
A minor update on the smaller CNC I'm building with the larger one...
Gantry parts are nearly all cut and assembled. The gantry is only loosely resting on the cart at the moment.
This shows the cut outs for the cart parts, the notch for the back boards, the holes for the steel rods.
On this side you can see the extra board that is used to adjust the "squareness" of the rails. (And also some of the scarring that is a result of the 'safe' height not being so safe....)
This little project is making it painfully clear that the big machine needs calibration, overhaul, etc. The holes are always too small, the edges are not 100% square and the big machine constantly stalls and I have to try and save the job...
So you have 1, 2, 20 boards to assemble and the last step is to solder the header pins.
Unlike components like caps or resistors where you can bend the wires on the solder side to keep them from falling through - headers cannot be bent. An even you did, getting the straight is a pain. Loose, they tend to look like this -
And, if you can get them to stay, when soldered that's where they'll stay. Ugly! So here's how I solved this. Using a breadboard. Start by getting all the headers ready.
Next insert them into the board - aligned with the holes in the circuit board.
Don't worry about getting them all the way. Place the circuit board on pins and using a flat edge press the pins into the board until at the desired depth (I'm using a razor blade - and I have had stiches, just not in my fingers - yet).
Now solder. Don't burn your fingers!
And voila! Nice straight pins.
