What have I got myself into
I knew/know nothing about machining but a lot about computers and software (I'm a linux sysadmin). Most of the hardware conversion was fairly standard. The purpose of this writeup is not to go through things step by step but to give an overview of the technologies used and the final result. I will generally note when something was tricky or any tips I used to make it easier.
First off, take whatever you think it will cost you and double it. I had budgeted about 5k for the conversion and tooling. I'm at 8k. I track everything I had to buy to make this happen, perhaps you already have a lot of tooling or other things needed. I didn't try to do the cheapest conversion possible, I simply wanted the best value for my time. For instance, I consider TTS tooling and a power drawbar mandatory because I can change a tool in 3 seconds vs 1 minute.
If I'd known it would have cost 8k I might have more seriously considered buying a Tormach or some other factory mill. But then I wouldn't have learned a lot, and that's half the fun. In case it isn't obvious by the time you're done rebuilding the g0704 you will have taken off pretty much everything but the frame.
I used the Hoss plans and the stock mill to make the mounting hardware for the x and y axes. I then used the stock acme leadscrews and the new x/y cnc control to make the z axis mounting hardware. With all 3 axes cnc controlled I made a set of mounting brackets for the chinese C7 ballscrews and a head and column spacer.
I had a local machine shop pocket the base for the ballnuts and y/z travel extensions along with adding oiling grooves because I don't have another mill and I wanted it done nicely. I did the head flip mod to gain z travel and put the whole mill back together. I tuned and tightened everything and I have backlash of .0015 which is acceptable to me.
I added a one shot oiling system, changed to a VFD 1.5HP motor with belt drive and added a hydraulic power drawbar. I also added limit switches, a completely new electronics enclosure and an auto z touch off tool measuring device.
I use LinuxCNC. It's free, quite good and you can use some advanced hardware with it. If you really want to use Mach 3 then I would skip all the talk about electronics. The Mesa hardware doesn't work with Mach 3.
Shoulders of Giants
Isaac Newton once said he only achieved what he did by standing on the shoulders of giants before him. The same applies here. I read, a lot. I have mainly borrowed ideas/concepts and actual code from people who were smarter. I try very hard not to re-invent the wheel. Where I can remember, I will attribute credit.
