My Last project (planning stage) Closed Bridge

[Stevie]

As the Gantry project is winding down; and the changes needed to the mini mill will not take long; my mind is wandering to the 8ft Hiwin ballscrew hanging in my garage
Some of you already know i want a long travel mill; however as space is getting limited in the work area (heaven forbid i start to use any of the old ladies space)
So i was about to think about cutting the ballscrew into 2 pieces; well a flyer arrived with a photo of a clased bridge mill; mind it was small 1000mm X travel
But the old thinking cap went on!!!

Using a modified version of what I saw; I feel a mill with a scope of work of 2150-2200mm by 600mm by 800mm is possible and keep the foot print to 2700-2800 by 1750 by = who cares it's vertical

So the basic structure is like my Gantry mill; but X axis is where my Y axis is; Z would be almost the same; while Y axis moves to the bottom of the machine and the rails are fixed to the base; imagine a shelf with Y moving across the width of the shelf; above is X moving down the length of the shelf with Z riding on X
The nice thing about the design is while the table is say 2250mm long as the ends of the machine are open; any length job can be tackled on there

This project will use the 3 P5 1000Kw servos with KTP's Pixies and servo drives
I already have the SR35mm rails for the Y axis; however the rest will be expensive; i'll have to buy new (Ho Noooo)

And while i hate to fabricate by welding; i guess a machine this big will have to be
4" by 4" 1/4 HSS wall might just be the ticket; i'll fill it with some damping stuff
It will also have to be left out for a season or 2 for stresses to be reduced; so yes this is a long term project
I have started a CAD layout of the basic structure; once i get the surfaces on I'll post an image

Open to ideas; suggestions