Strengthening the mill column
It took 2 whole days for the conversion, one of which was spent just "tramming" (realigning to vertical) the column!
This type of mill has the ability to tilt the column ± 45 ˚ to make angled cuts. Generally, however, it is preferable to angle the workpiece in the vise instead of the column, since realigning the vertical column can be a lengthy procedure.
Given that one single bolt connects the mill’s column to its base, and the considerable suspended weight of the head (about 40 lbs or 20 kg), it is possible that vibrations occurring during big cuts, might swing the cutting implement (forward / backward) and reduce accuracy.
Using a precision indicator positioned over very accurate “123 blocks”, I measured these deviations by applying moderate pressure on the head of the mill (forward / backward).
The deviation recorded by the indicator was ± 0.001 inches (0.0254 mm). After completing the project of strengthening the tower of the mill, this deviation is reduced to ± 0.0005 in. (0.0127 mm).
Although it doesn't sound like much, this actually translates into a 50% improvement.
For comparison purposes, the average width of a human hair is 0.004”, and we are talking about a movement that is 8 times smaller than that! So, we are literally "splitting hairs".
Unfortunately, the process of realigning the column has become much more involved, since now each bolt wants to impart its own small torque to the column during tightening.
All in all, I think that the gain in precision obtained by this modification justifies, even if only slightly, the increased complexity of the realignment process. Procedure which fortunately will be much less necessary thanks to the update.
This conversion has the added advantage of making the X2 mill a better CNC platform, should I choose to move in that direction.
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| Looking at the back side of the mill |
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| Adding the back brace |
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| Bracing completed |
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| "Tramming" setup |
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| Left side view of the modified mill |
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