I've been building a CNC machine so I can create my own parts in the shop. 
The logic to start this project  went as follows:

I want to build A UAV...but
I needed special parts... so
I need to build a CNC...

The UAV is already done now, but this will help me refine and enhance the plane and a million other projects! I have developed a truly great respect for machinists.

So I finally got it together, tuned enough to cut plastic and make a few parts. In tribute to my tech past, here is my first clean 'hello world' in thick plexi. Not perfect but not terrible either..
Plastic has the tendency to either chip or melt on your cutting blade. So the feed rate and spindle speed and bit are all important. I don't pretend to have it all down as there is a field of expertise out there that far exceeds my capability, but I am learning!

Wood is much easier - highspeed spindle and whatever bit plus a good feedrate.  I also have circuit board cutting planned as I received my bit set. Programmer away!

counters for myspace