Hey NIC,
That is more or less the latest design, though I added feet to the two columns. I will also be closing the gap between the columns once I know where the will be, etc. It will be quite the challenge to make those 3 individual pieces coplanar to each other.
You are correct, only area under the 45mm rails on the two vertical columns will need to be square to the base table. The table itself is ground flat so that will be my datum for everything else.
I'm right handed but I'm pretty sure I was born with two left hands. My arms could've been tree trunks as far as my control and artistic ability go. I'm going to need some sort of machine to help out with this.
The idea behind grinding the columns was to use two rails mounted to the table. A 'cart' bridge would be built with a rail on each side of the column while it's sitting flat on the table. I have a grinder mount for the lathe (somewhere) and a Precise grinder/spindle I thought I could use. Where the flying pig comes in is that the contraption will probably take longer to design, build and proof than the rest of the machine.
I did try to find a nearby CNC shop years ago with a large enough, proper surface grinder to fix the Bridgeport but no one I contacted had it. Perhaps I should try that again.
That looks like a good machine in your link. I also found a nearby "compact" VMC that looked great and had a reasonable price. The damn thing is 10,000 pounds (4500 kg) and would barely fit through my garage door. Plus, by the time these machines make it to us garage warriors they are beaten to near death, need a bunch of parts that in many cases are no longer available, require 3-phase power or converter and an industrial size air compressor that's equally large as it is loud.
Regards,
JR