Another chapter in the unfolding saga of my education as a machine tool tech.
While using the Millrite MVI to mill the ends of mild steel bars off square, I noticed something odd. When moving the table in and out in the Y direction (closer and farther from the column) with the table clamped in the X-axis direction, cutting would happen only in the conventional-milling direction, and no cutting would happen in the climb-milling direction, unless I moved the table in the X-direction (side-to-side).
The bar is held in a milling vise, the bar being parallel to the T-slots in the table, with the left end being presented to the side of the cutter (6 helical flutes, 1" in diameter).
As I'm cranking the table in and out I'm wondering what could cause that. Clearly, there is some unintended X-axis motion due to the intended Y-axis motion, despite the X-axis being clamped. So, I used the Skoal optical centering scope to test the theory, finding that reversing Y-axis direction causes a ~0.0028" X-axis motion. That's a lot, and certainly explains why the mill would cut only in one direction, and also why I had some difficulty cutting the bars to a specified length.
Cause? The Y-axis feedscrew is on the right side of the saddle, so if the saddle-to-knee gib is loose the saddle will c*ck one way when being cranked closer to the column and will c*ck the other way when being cranked away from the column. So, time to adjust the saddle-knee gib. This was easily done, and eliminated the X-axis motion due to Y-axis motion. I wonder when that gib was last tightened.
What I have not yet done is to tighten the table-saddle (X-axis) gib, as this requires removal of the table-saddle assembly from the mill to get access to the adjustment screws and setscrews. Given the difficulty, I bet this gib has never been adjusted. The X-axis feedscrew is in the center, so cocking would be more random and thus more confusing than in the Y-axis. Table removal isn't difficult, but requires a small hoist. I don't have the space to store such a hoist, but they can be rented from the local Taylor Rentals place.
Or, I can hang the table from the ram with welded-link chain and quick links and eyebolts bolted to the table, undo and remove the saddle-knee gib, and crank the knee down leaving the table-saddle assembly dangling from the ram. Perhaps I can then tighten the table-saddle gib on the dangling assembly. I'll have to work out the details of how this would be done safely. And the Y-axis DRO will have to be removed. I already have the eyebolts and matching thick washers and T-nuts, bought precisely to allow secure attachment for safe lifting of the table.