Delta 11-990C - Manual (Page 12)

12
SPINDLE SPEEDS
Five spindle speeds of 620, 1100, 1720, 2340 and 3100
RPM are available. The highest speed is obtained when
the belt is on the largest step of the motor pulley and the
smallest step of the spindle pulley, as shown in Fig. 28.
Fig. 28, illustrates which steps the pulleys the belt must
be placed to obtain the five speeds available.
Fig. 28
SPINDLE
MOTOR
3100
2340
1720
1100
620
CHANGING SPEEDS AND
ADJUSTING BELT TENSION
1. Disconnect the tool from the power source.
2. Lift up the belt and pulley guard (A) Fig. 29.
3. Release belt tension by loosening tension lock knob
(B) Fig. 29, and pivoting the motor toward the front of the
drill press, as shown.
4. While holding the motor toward the front of the drill
press head, position the belt (C) on the desired steps of
the motor and spindle pulleys, as shown in Fig. 29. A
belt positioning chart (D) is provided on the inside top
cover of the drill press for your convenience.
5. After the belt is positioned on the desired steps of
the motor and spindle pulleys, pivot motor away from
the drill press head until the belt is properly tensioned
and tighten tension lock knob (B) Fig. 30. The belt
should be just tight enough to prevent slipping.
Excessive tension will reduce the life of the belt, pulleys
and bearings. Correct tension is obtained when the belt
(C) can be flexed about one inch out of the line midway
between the pulleys using light finger pressure.
DRILLING HOLES TO DEPTH
Where a number of holes are to be drilled to exactly the
same depth, a depth stop is provided in the pinion shaft
housing and is used as follows:
1. Loosen lock screw (A) Fig. 31, and rotate housing (B)
until the pointer (C) lines up with the desired depth
indicated on scale (D). Then tighten lock screw (A).
2. All holes will then be drilled to the exact depth as
indicated on scale (D) Fig. 31. NOTE: Scale (D) is
calibrated in both inches and millimeters.
Fig. 31
C A
B
D
A
Fig. 29
B
C
D
Fig. 30
C
B