I'm about 90% complete with my JGRO-based CNC router. I have the entire gantry setup done, the motors and leadscrews for the Z and X axes are complete, and the ends of the Y axis are built, etc. I needed to take a break for a bit to rearrange my shop so I had room for the completed unit, and I took the time to build a table for it to sit on. It's the details that take all the time!
So tonight I'm going to get the rough alignment of the Y axis going. My initial assessment indicates that there might be something wrong with my guides on the gantry, since there seems to be a significant gap on part of the bearing assembly. I took the time to level the table, and then used that to ensure that the Y axis pipes were level and fairly close to alignment, and since I have a fairly big gap I have to assume it's a goof somewhere else.
Another thing I learned while working on this is that since I subbed out a lot of the MDF for birch plywood, that small fractional dimension difference is starting to matter in a few critical areas. 3/4" MDF is just that. 3/4" plywood is typically 1/32" or so thinner. In the case of the gantry width, the design has you stack 6 pieces together (bearing block, gantry side, corner block for each side), and so that small difference starts to add up. I suspect I'll want to redrill the Y axis pipe guide holes so that I have more alignment space.
I still need to figure out what kind of router I'm going to start with and build an appropriate mount. I think for my initial testing and tramming I'm going to build a pen mount, making this an extremely overdesigned plotter.