I think I've already mentioned that I'm an engineer at a major manufacturer of CNC machines.
A substantial part of my work involves designing machines/parts in SolidWorks (3D CAD software).
Now, obviously I can't show these particular designs here, for reasons of IP and trade secrets - but I also have my own designs in that field, and these I can
Here's a particularly pertinent example.
It's the (largely incomplete)
design for a highly capable (for its size, at least) bench-top "mini mill" of cast granite (aka "epoxy granite") construction, which for a time I had seriously contemplated building.
As it stands now, the design is little more than a proof of concept - in that yes, it can indeed be done, while still meeting the original specification in most respects.
Obviously, a lot of the parts have been rendered transparent for clarity - no, it's not actually made of glass
To give a sense of scale: the side of the whole cube is approx. 70cm (27") long, and the machine would've weighed approx. half a ton if built as designed. (yes, very heavy for its size - but it pretty much needs to be, if it's to be capable of roughing prehardened steel, as intended)
The working volume is 390x280x155mm (X*Y*Z).
The total cost of materials, machining, off-the-shelf parts, and R&D/NRE expenditures is in the range of $15-20k.
That's including a refrigeration system for keeping the machine's temperature stable, which helps a lot
with dimensional accuracy.
Here's a better view of the Y axis components:
The X axis design is largely just a placeholder, but the overall idea was along the same lines as for the Y axis - that is, a cast-in prefabricated steel subframe to hold the rails and ballscrew bearings, which would then have the relevant surfaces machined only after casting the whole granite panel.