For a while, I have been looking at building a new milling machine.

This is the design I came up with. The machine will be primarily for aluminum and maybe some mild steel. The base will be cast out of concrete within the frame.
I will be running flood cooling, so there are also 3 x 100mm drains in the base which will run into a catch tank under the table. This will also be for chip collection.
The cutting area will be 750 Y, 900 X, 250 Z

50 x 50 x 5mm square tubing filled with concrete for the frame.
50 x 5mm angle for all the rail mounts with nuts welded under for more thread strength.
HGR20 Linear rails and bearings
1500mm Y, 1000mm X, 500mm Z
Sika Shrink compensated cement for the concrete mix for the base with 4 layers of 10 x 50mm grid reinforcing mesh
(this is for weight and volume to reduce vibrations and increase rigidity)
Nema 23 3nm motors with 24tooth 15mm HTD belt pulley on all the axis
1605 Ballscrews with 60tooth 15mm HTD belt pulley on all the axis

Today I got the frame weld up. Hoping to have all the plugs and hardpoints done in the next 2 weeks.
Then will be on to the casting. It will be left to cure for about 40 - 60 days. In that time I will be building the mold for the gantry.