Optical Table CNC Lathe - Increased Y Axis Stiffness

The vibration and cutting tests indicated that I needed a stiffer y axis in the sense that it would allow deflection in the direction perpendicular to the table surface too readily. The two weak spots were primarily the cross roller bearings in the Parker stage and secondarily the stiffness of the aluminum cross member itself. To address this, I first replace the aluminum cross member:

The original is basically a beam with a 6x0.75 inch cross section. As we can see, the area moment of inertia of this beam will increase 8 fold with a doubling of the height:

Which is a good start:

I did rub a flat file on the top of the surface, similar to the precision ground toolroom stones as described here:

I learned this from a tool and die maker. Every time a workpiece is cut or drilled the parts next to the machined area tend to have raised areas. I am sure the stones work even better, but a file works great too, as long as its very flat and pressure is evenly applied. Similar to the stones, the file will only grab on raised areas, as otherwise the unit pressure is not enough to bite. At a low angle of light, the flattened areas especially around the drilled bolt holes are visible. The aluminum manufacturers tooling marks are visible as well. This is on nominally flat MIC-6 tooling plate:

The second stiffness issue to address is the parker stage. This was completely replaced by LRX45 rails. Here is a size comparison, with the parker stage laid on top of the LRX45:

Aside from having much stiffer rollers, the LRX rails will add to the stiffness of the beam, as well.

So now the new Y axis looks like this: