Epoxy granite vertical mill build log

[Nick]

Right so I've started on an large cast iron/EG mill build. Plan is to use several cast iron surface plates I have bought on ebay and embeded in epoxy granite, the hope is this will give me a flat surface to mount the linear rails to.

This is the current design in fusion



Travel: X 400mm, Y 250mm, Z 400mm
Total weight 600-800kg
Rails: 20mm hiwin clone rails
Ball screws: Generic rolled Chinese ball screws, with a plan to upgrade in the future.
Spindle: Initially: 2.2kw water cooled spindle. The plan would be to upgrade to a BT30 and 1.8kw servo from AliExpress if I can get this made and then integrate ATC
Electronics: UC400 ETH, Initially steppers, with upgrade to 400W AC servos.

Epoxy granite: Silimix 282 + west systems epoxy 105/206 10% by weight, 0.25% black iron oxide


Cast iron:
I’ve got one 36 x 16 inch plate



Along with four of these 18x12x2in plates



The large surface plate is reasonably flat, however the smaller plates are out by about 0.05-0.15mm. I am planning on trying to hand scrape them flat.

Issues:
1. I have got to cut one of the cast iron plates into four for the column mounting blocks, I’m not sure how I will do this as they're 2 inch's thick, I think I will try with a cutting disc
2. The column and table will consist of more than one cast iron piece, I’m not quite sure what the best way to keep alignment is, I think I will have to use a flat surface, possibly the big surface plate to cast against and an angle plate.


I've got the epoxy and Silimix. I have made the mould for the base and I think I will cast this first to check that the epoxy granite doesn't warp the surface as it sets. I'll post back with the results!