Jet ZH Series, Operation And Maintenance Instructions

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14.0 Troubleshooting the ZH Series Lathes
Table 2
Trouble Probable Cause Remedy
Lathe will not start.
No electrical power, or wiring incorrect.
Verify incoming power, main leads, main
switch is on.
Emergency stop switch is pressed. Rotate switch clockwise to release.
End gear cover open, limit switch
activated.
Close cover.
Fuse blown in main electrical box. Replace fuse.
Fuse blown/circuit breaker tripped at
power source. Reset. Verify incoming power is proper for
lathe.
Defective on/off switch, motor or cable. Have electrician test elements.
Foot brake switch is faulty. Check and replace as needed.
Thermal relay tripped.
Reset. If it trips frequently, increase amp
setting.
Spindle lacks turning
power; or starts up
slowly. Friction clutch is slipping. Adjust clutch.
Belts are slipping. Tighten belts.
Excessive machine
vibration.
Workpiece unbalanced. Reduce spindle speed.
Workpiece deflecting.
Change chucking length or diameter. Use
support on tailstock end.
Tool deflecting. Reduce tool length.
Backlash on slide ways/gibs. Adjust backlash.
Slides running dry. Properly lubricate slides/ways.
Tool edge is dull. Resharpen or replace tool.
Chip load too high. Reduce depth of cut or feed rate.
Spindle bearings out of adjustment. Adjust bearings.
Belts misaligned. Inspect belts and correct.
Lathe overheating.
Bogging down in cut; excessive feed rate
or depth of cut.
Decrease feed rate or depth of cut.
Tool tip burns.
Cutting speed too high. Reduce speed.
Tool is dull. Resharpen or replace.
Lathe turns a taper.
Tailstock not aligned with headstock. Align tailstock.
Lathe bed is twisted. Correct by leveling lathe.
No automatic power
feed.
Shear pin is broken. Replace shear pin.
Carriage, cross slide or
compound rest move
with difficulty.
Carriage lock is tightened down. Release carriage lock.
Gibs are too tight. Adjust using gib screws.
Bed ways have shavings/debris on them;
or are dry. Clean ways and verify they are being
lubricated properly.