Hi everyone!

I've always loved CNC machines, and while I have done a more practical conversion in the past, I've always wanted to convert a mill for fun, without any real goal other than building something awesome. I've chosen to start with a g0704 because it is capable but also fairly small and light.

This build is going to be my pet project for a while and I'll do my best to turn my g0704 into a fully featured and polished cnc conversion.

This is my preliminary todo list for the first stage of my conversion:
  • Check the machines accuracy and scrape as necessary
  • Double preloaded ballnuts on all axes
  • Servos
  • Glass Encoders on all axes
  • Fourth/Fifth Axis
  • Extended Travels
  • Automatic Oiler
  • Stand that integrates column support


I will be paying special attention to how several of the mods are performed (5th axis, extended travels) to ensure rigidity and accuracy are not compromised.


I am cheating a bit with my buildlog as I started this conversion a few months ago. I didn't have as much time back then and the work was more repetitive though so this just lets me keep the thread interesting.


Anyways, I've been reading about scraping and I picked up a copy of machine tool reconditioning so the first step is to make a straightedge. I am going to have to warn everyone I've never done this before and I really don't know what I am doing. The process seems logical enough though.

I started with a 2' length of cast iron bar.

Unfortunately, a 16" straightedge was at the absolute limits of my current mills travel and I needed to be very creative to get it cut. Going all the way to the ends of my travel wrecked the accuracy and the surfaces are convex by about 5 thou.


I quickly discovered it would be very tedious to scrape that flat by hand so I cheated and used an orbital sander + dremel to get it somewhat flat.


Spots alright, but the dremel does leave some pretty deep scratches. Not really something you are supposed to do, but the results seem okay.


I checked the dremeled surface with an indicator, the bumps are about 0.3 thou above the low spots.


And properly scraped, I had to remove a fair deal more material to get it to spot nicely without scratches.

I left the straightedge fairly flat but not entirely finished, I spent two and a half days scraping the thing and I won't actually have that many uses for it.