Grizzly G0791, Owner'S Manual

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Model G0791 (Mfd. Since 9/15)
Downfeed Controls
Identification
A. Quill Lock Bolt
B. Depth Scale Lock Knob
C. Coarse Downfeed Handles
D. Downfeed Selector Knob
E. Depth Pointer and Scale
F. Fine Downfeed Handwheel
Figure 101. Downfeed controls.
C
D
F
B
E
A
Coarse Downfeed
Coarse downfeed is typically used for drilling
applications. Loosen the quill lock bolt, pull out
the down feed selector knob, then rotate either
of the coarse downfeed handles (see
Figure
101) to lower the spindle. An internal coil spring
helps raise the spindle back to the top position
when you stop applying downward pressure on
the handle. Spindle travel is shown on the depth
scale, and is limited by the depth pointer when the
scale lock knob is secured.
Note: To maintain control of the upward spindle
travel and the rotating bit in your workpiece,
always continue holding the handle until the
spindle returns to the top position. Letting go of
the coarse downfeed handles when the spindle
is in the lowered position will cause the spindle to
retract too quickly and slam up into the headstock
or lift the workpiece and cause it to spin out of
control.
The coarse downfeed hub features a graduated
dial that measures spindle movement in 0.02"
increments, with one full revolution equaling 2.40"
of spindle travel.
Fine Downfeed
Fine downfeed is typically used for milling appli-
cations, because the spindle only moves up or
down when the fine downfeed handwheel (see
Figure 101) is rotated (there is no automatic spin-
dle return to the top position, as with the coarse
downfeed controls). This allows the spindle height
to be locked in place for precise Z-axis positioning
of a cutter or end-mill when milling a flat surface
across the face of a workpiece. In order to ensure
the milled surface remains flat, the spindle height
cannot move until the entire milling operation is
complete.
The fine downfeed graduated dial measures spin-
dle movement in 0.002" increments, with one full
revolution equaling 0.092" of spindle travel.