21
10.0
Spindle Speed Chart
Note: A similar chart is found on the front of the drill head.
6-Step Spindle Speed
Settings
for J-720R Radial Arm Drill
Low Speed
High Speed
1
2
3
4
5
6
Speed (RPM)
60Hz
88
154
282
455
796
1500
50Hz
73
128
234
378
662
1247
Suitable drilling
diameter (inches)
Steel
1-1/4 ~ 31/32
31/32 ~ 3/4
3/4 ~ 15/32
15/32 ~ 3/8
3/8 ~ 7/32
7/32 ~ 1/8
Cast Iron 1-31/32 ~ 1-1/2 1-1/2 ~ 1-3/32
1-1/32 ~ 7/8
7/8 ~ 3/4
3/4 ~ 3/8
3/8 ~ 1/8
Tapping (inches)
7/8 ~ 5/8
5/8 ~ 7/32
7/32 ~ 1/8
Not recommended
Table 3
11.0
Troubleshooting J-720R Radial Drill Press
Trouble
Probable Cause
Suggested Remedy
Spindle overloads,
causing relay to trip.
Drill bit is too large.
Turn off power, wait three minutes after
spindle stops turning, then push the re-set
on the relay in the control box.
Correct initial problem by using shorter
drill bit or lower feed rate; consult
appropriate feed and speed rate tables.
Replace fuse if needed. Verify proper
voltage at power source.
Feed rate too fast.
Operation not in compliance with speed
and feed rate tables.
Fuse is burned out.
Low voltage.
Spindle overloads,
causing fuse to blow.
Drill bit is too large.
Replace fuse in control box.
Correct initial problem by using smaller
drill bit or lower feed rate; consult
appropriate feed and speed rate tables.
Feed rate too fast.
Operation not in compliance with speed
and feed rate tables.
Table 4
If drill bit gets broken in the spindle:
1. Move arm/spindle control lever to neutral.
2. Press emergency stop button.
3. Push the head/gearbox out of the way.
4. Pinch the end of the broken bit with pliers.
5. Rotate counterclockwise and pull it out upwards.
If screw tap gets broken in the spindle:
1. Move arm/spindle control lever to neutral.
2. Press emergency stop button.
3. Using a thread releaser, rotate the screw tap counterclockwise until it comes out.
If something becomes entangled during operation:
1. Press emergency stop button.
2. Disconnect power.
3. Switch speed change lever to highest gear.
4. Rotate spindle by hand in reverse direction from that used during the operation, until the obstruction is free.
Summary of Contents for J-720R
Page 9: ...9 General Features and Terminology cont Figure 5 2 ...
Page 14: ...14 7 0 Operating Controls J720R Figure 7 1 Operating Controls ...
Page 23: ...23 Figure 12 1 Figure 12 2 Figure 12 3 Figure 12 4 Figure 12 5 ...
Page 27: ...27 13 3 1 Base Column and Arm Assemblies Exploded View ...
Page 30: ...30 13 4 1 Gear Box Assembly Exploded View ...
Page 34: ...34 13 5 1 Rear Gear Box Assembly I Exploded View ...
Page 35: ...35 13 5 2 Rear Gear Box Assembly II Exploded View ...
