It's very difficult to get the column exactly perpendicular to the base using just shims. Additionally, temperature can make the column lean more one direction or another. What I did was fabricate a bracket which is bolted to the base using the column's mounting bolts (longer bolts were required), and then connect the bracket with the top of the column using turnbuckles. Both the side and back of the column received a turnbuckle. Now, as I tighten or loosen the turnbuckle, it will push or pull the column slightly to account for any slight misalignment.
The turnbuckles actually bend the column, so the amount of movement becomes greater the closer to the top of the column you get. Therefore you can't use this system to get the column exactly perpendicular to the base at every position on the column. However, once you've done the best you can with shims, this will let you get it a little closer still, and I'm happy with an incremental improvement.
The rod ends were stock items purchased from McMaster. The turnbuckles themselves were created from 1/2" mild steel rod. The ended were turned down and then threaded on my mini lathe. One end is right hand thread, the other is left hand thread. A M14 nut was slide down the turnbuckle and then welded in place, giving a convenient way to turn them.
The power box was spaced away from the column using simple standoffs to make room for the turnbuckle.
As an added bonus, the bracket was is an ideal location to put my mill's DRO's control box and let me clean up the wires.
|The system installed on the mill.|
|The bracket the bottom of the turnbuckles attach to.|
|Top of the turn buckles, and the power box spacers.|
|The DRO control box on the bracket and the wires corralled.|
UPDATE: I ended up taking it back off the mill. In practice it proved pretty hard to use, and my column is already close to perfect that it just didn't make sense to keep it. Removed it also allowed me to move the spindle light and power feed control back to the top left of the column.