On every other machine the flatness of the base plate is critical. These machines need it to be precision-ground so that the mast will remain in the same orientation as it slides back and forth along the base plate.
For the Omni, this is not as big an issue as the Faceting Head and Mast are mounted on the Swing Arm instead. It still is important though, as the Swing Arm and Base Plate must remain in alignment as the Swing Arm moves in and out.
It also becomes an issue when you want to align the Mast perpendicular to the Base Plate, or if you wanted to use a dial indicator to align the Platen to the Base Plate. Without something accurate to measure against, you have no clue what part is oriented correctly or not.
I discovered the problem when I tried to adjust the Platen Tilt using a dial indicator attached to a base sitting on the Base Plate. After a few minutes I stopped as it was obvious the Platen was getting completely mis-aligned by this method. I then took a machined piece of tool steel and placed that on the Base Plate and measured it with the dial indicator. After moving both the block of steel and the dial indicator base I realized the Base Plate was too warped to use for aligning the Platen.
Here are a series of photos I took holding a metal straight edge against various parts of my Omni’s Base Plate. If it were flat, you wouldn’t see even a sliver of light between the edge and the Base Plate. Or you would see a very thin but even line of light along the straight edge.
As you can see for yourself, the Base Plate warp is pretty severe in some places and not consistent across the surface.
The Base Plate is about 5/8″ thick, which should be more than sturdy enough to withstand the weight of any components mounted on it. And it’s far too thick to be warped by using the machine. To warp or bend this thickness of metal you’d leave behind obvious dents.
My conclusion is that the Base Plate was never machined flat in the first place. Which again calls into question the workmanship and quality of the Omni Faceting Machine construction.
How does this affect the machine? It makes it almost impossible to align the components as there is nothing accurate to measure against. Trying to find something to Align the Mast to was an interesting challenge.