For starters, I made the y-axis support plate, it was machined from solid and has two tracks with .1875 Radius machined in the centers to support the rails.
Each rail has five #6-32 SS SHCS holding the rails in position. The rails were reilled and counterbored using Carbide 4-flute ball end mills, and a flat bottom carbide endmill for the c-bore.
The 1st problem I had was the warpage in the rails when I drilled the holes, they curled up instantly! The problem was solved by drilling the c-bore first, as the larger end mill went through the case hardened skin of the rails easier. Then I drilled the small hole with the ball end mill. The rail was over heating as the ball endmill went through both case hardened skins!
After a little straightening on the surface plate with an indicator and v-blocks, the rails are now ready!