10
PM 25MV v9 2021-12
Copyright © 2021 Quality Machine Tools, LLC
MOVING THE TABLE
Conventionally, left-right movement of the table is said
to be along the X-axis (also called “longitudinal travel”
or “traversing”). Front-back movement is on the Y-axis,
sometimes called “cross travel”.
Each axis has a leadscrew with handwheel and gradu-
ated dial with 0.001” divisions, 0.1” per revolution. If the
Figure 3-4
X-axis locks
Figure 3-5
Y-axis locks
RAISING & LOWERING THE HEADSTOCK
The Z-axis crank, Figure 3-6 inset, is at the top right of
the column. If the mill has a 3-axis DRO the headstock
position is displayed at all times. If not, the headstock
can be positioned approximately by reference to a 12”
scale on the column. For more precise positioning the
crank hub has a graduated dial with 0.001” divisions (be
aware of backlash in the bevel gears controlling the Z-
axis leadscrew, and also in the leadscrew nut).
When the headstock is at the desired height, lock it in
place.
All milling operations should be
done with the quill as fully retracted
into the headstock and locked.
Figure 3-6
Z-axis locks
In operations calling for precise depth
control, such as milling, both quill and
headstock must be locked to maintain
a precise depth of cut.
mill is not equipped with digital readouts (DROs), the
table can be accurately positioned by counting whole
turns and divisions, keeping
leadscrew backlash
in
mind. This means that table motion must always be in
the same direction up to the point of reference, then on
to the desired location, see “Positioning by Counting X-Y
Divisions”, two pages on.
