Neale I was hoping you might reply. It's good to hear about the steel cuts, that is good news for cutting ipe, an extremely dense hard wood. As far as cutting the holes I could have 300 or more in 12 - 20 mm steel. Most holes are 16 mm. I put an image of a typical table jig in a previous post. The reason they need watched is because it doesn't leave chips it makes birds nests, and a lot of them. This is a stock video of an annular cutter and mag drill https://www.youtube.com/watch?v=N7Pef3zFj7Q in action. It only takes about 30 seconds to drill but a long time to clear and re position. If you look at the machine in the video I'm thinking of taking that motor and mounting it on the z axis for the drilling spindle, and a second z axis for routing.

What do you think of using rectangular tubes for x axis maybe 50 x 100 mm? Mainly for torsional load. I see you made your z axis out of aluminum. I'm thinking making that out of steel also, welded 5 mm plate. Assuming I can keep it flat enough. This is looking more like prototyping and cheap and easy seems the way to go.