520052, this is my main concern. but on the other hand I won't be hogging cubic meters/min on this machine.
I wanted to do this machine by myself at my workshop. if i would choose any other material i would need some engineering shop to ground flat 1 meter long gantry. And it doesn't matter if it is steel aluminium or something else. it has to be ground flat.
this would cost a fortune, in addition i will have to wait for them to find time to do this.
making it out of granite i skipped this problem because granite is already incredibly flat. as i checked it was as flat as my surface plate.
gantry is 190mm tall 50mm thick and 1030mm long. so it is quite solid piece of stone. I had an accident where i dropped one of the sides on the concrete floor. for the split second i thought it will shatter but nothing happen. so this give me a bit more confidence.
on the other hand spindle is mounted to the z axis through rails and than this is mounted to the gantry through the rails.So this should distribute the force quite uniformly.
anyway i'm still a bit worried about it. but if it crack i will make replacement out of epoxy-granite. even cracked i still can use it as my new gantry face for the mold.
ITCO, base is granite, side walls are granite, gantry its granite, everything else is not.
smlua, bzen, thanks guys, i'm glad you like it