Advertisement
Excessive cutter noise, chatter, poor finish
and tool wear are often the result of too
high a feed rate, and/or too high a spindle
speed. If unsure, go slow!
INSTALLING & REMOVING TOOLING
The spindle and drawbar are designed for R-8 taper
collets, drill chucks and other arbors with the standard
7/6"-20 internal thread. The drawbar is threaded into
the R-8 device by a few turns of the upper nut, which
is solidly pinned to the bar. With sufficient length of the
thread engaged, run the lower nut down as far as it will
go, then tighten it using two wrenches, 7 mm upper, 9
mm lower (or /6" and 3/4"). To keep the spindle from
turning too freely in this procedure, select a low speed
such as L-. Another way of tightening the lower nut is
to hold the spindle using a 6-spline wrench, nominal size
28 mm.
To remove the R-8 device, loosen the lower nut one half
turn or less, then tap the top of the drawbar with a brass
or dead-blow hammer to unseat the taper. Unscrew the
drawbar by turning the upper nut with one hand while
supporting the R-8 device with the other hand.
Replace the drawbar cap to protect bearings and
spline.
Figure 3-3 Spindle and drawbar
PM-940M 0-206 v.indd
Keep in mind that the table, vise and work-
piece can be damaged by falling tools and
drill chucks. The cutting tool itself can also
be damaged in the same way.
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 0.00" divisions, 0." per revolution, Fig-
ure 3-4. If the 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 refer-
ence, then on to the desired location, see "X & Y axis
positioning", following.
Figure 3-4 Y-axis handwheel and X-axis locks
The limit switch assembly, arrowed, prevents over-travel when
the X-axis is power driven. Separate microswitches, left and
right, are actuated by adjustable spring-cushioned stop blocks
(3).
Be sure to loosen the X-axis lock screws
before moving the table, especially under
power
2
Advertisement
