In my March 29th post, I mentioned that the FEA torsional stiffness of the column was twice the value I got when I measured the mill after modifying it. I attributed that to the fact that the two side plates were bolted to the inside of the column and not one piece as in the model. I mentioned that I would consider epoxying the bars to the inside of the column if I had to access the area in the future. Well, the future is here. I epoxied the bars and increased the size of the pins attaching the back plate. The results were impressive. The column is now 4 times stiffer in torsion then the original modification. I was curious about the stiffness of the head stock in the X direction and so I performed a similar measurement to see what the stiffness is. Low and behold, the head stock is now more flexible than the column. I have been away for awhile and as such haven't tried the mill with the mods. I'll post my thoughts on how much, if any the mill has been improved when I actually use it.
I've attached a .pdf of the updated report I wrote. The update discusses the recent mods.