On Mar 10, 3:26*pm, wrote:
I am a beginner

I have the Sieg X2. *The Cummins version. *I want to make the Z-axis
as square to the table as possible and I don't know how. *I want to
drill very straight holes.

I see that the head can be adjusted side by side. *By loosing the big
nut in back. *How do I make sure this is as straight as possible? *I
have used a square and eyeballed it. *How would I use a test indicator
or Dial indicator to make it more accurate?
...
How square front and back do the Sieg X2 mills come out of the box?
How would they compare to a quality drill press?

Don't know, you'll soon find out.

I have collets for the bits I need to use. *But how accurate is the
standard chuck that comes with the mill?

When you tram the mill, chuck runout doesn't matter.

Unplug the mill so you don't accidently damage the Space Station with
the indicator.
Disconnect the drive if it's easy. You want the chuck to turn easily
by hand.
Center the table under the spindle, by eye is good enough.

Get a piece of steel rod that the indicator will clamp onto and bend
it L shaped. A 6" piece bent somewhere near the middle is fine,
nothing critical here, length or angle. The thicker the better, within
reason. 1/4" steel welding rod or CRS from the hardware store should
be fine.

Chuck one end of the bent rod, attach the indicator near the outer end
of the horizontal leg, point down.

I like to use a parallel here, to keep the indicator point out of the
table slots. Lower the head until the point contacts the table or top
of the parallel. Swing the rod to the other side and see if it touches
there yet.

Make crude adjustments to get the reading on the dial on both sides,
then zero it on the lower reading side (indicator point further out,
column tilted away), swing it to the higher reading side, figure half
the difference and tap the column toward the low side until the
indicator is close to the half reading. Recheck the zero side, see if
it's close to half. Repeat until satisfied or bored.

Tightening the bolts on my mill changes the adjustment slightly but
predictably.

Before checking front-rear tilt, snug up the gibs. You may find that
it's only square at one setting, such as tightly clamped to the
column.

I used a mill-drill that was off by ~0.009" in 5" and never noticed
any effect on the work. While checking spindle squareness I also
looked at runout in the table motion. On that particular RF-31 moving
the table didn't change the indicator by 0.001 but the slots weren't
quite parallel to the X axis. The front edge of the table was, so I
used it to set large pieces parallel.

Jim Wilkins