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Lathe
Symptom
Possible Cause
Entire machine
1. Workpiece is unbalanced.
vibrates upon
2. Loose or damaged V-belt(s).
startup and while
3. V-belt pulleys are not properly aligned.
running.
4. Chuck or faceplate is unbalanced.
5. Change gears not aligned or no backlash.
6. Broken gear or bad bearing.
7. Workpiece is hitting stationary object.
8. Spindle bearings at fault.
Bad surface finish.
1. Wrong spindle speed or feed rate.
2. Dull tooling or poor tool selection.
3. Tool height not at spindle centerline.
4. Too much play in gibs.
Tapered tool difficult
1. Quill not fully retracted into tailstock.
to remove from
2. Contaminants not removed from taper
tailstock quill.
before inserting into quill.
Cross slide,
1. Gibs out of adjustment.
compound rest, or
2. Handwheel is loose or backlash is high.
carriage feed has
sloppy operation.
3. Leadscrew mechanism worn.
Cross slide,
1. Dovetail ways loaded with shavings, dust,
compound,
or grime.
or carriage
2. Gib screws are too tight.
handwheels hard to
move.
3. Backlash setting too tight.
4. Bedways are dry.
Cutting tool
1. Tool holder not tight enough.
or machine
2. Cutting tool sticks too far out of tool holder;
components vibrate
lack of support.
excessively during
3. Gibs are out of adjustment.
cutting.
4. Dull cutting tool.
5. Incorrect spindle speed or feed rate.
Workpiece is
1. Headstock and tailstock not properly
tapered.
aligned with each other.
Chuck jaws will
1. Chips lodged in jaws or scroll plate.
not move or do not
move easily.
Carriage will not
1. Gears not all engaged.
feed or is hard to
2. Half nut lever engaged.
move.
3. Loose screw on feed handle.
4. Carriage lock is tightened down.
5. Chips have loaded up on bedways.
6. Bedways are dry and in need of lubrication.
7. Gibs are too tight.
8. Gears broken.
Gear change levers
1. Gears not aligned inside headstock/quick-
will not shift.
change gearbox.
-84-
Possible Solution
1. Re-install workpiece; center with spindle bore.
2. Retension/replace V-belt(s) (see Page 89).
3. Align V-belt pulleys.
4. Rebalance chuck or faceplate; contact a local
machine shop for help.
5. Adjust change gears and establish backlash.
6. Replace broken gear or bearing.
7. Stop lathe and correct interference problem.
8. Reset spindle bearing preload (Page 91) or replace
worn spindle bearings.
1. Adjust for appropriate spindle speed and feed rate.
2. Sharpen tooling or select a better tool for operation.
3. Adjust tool height to spindle centerline (Page 41).
4. Tighten gibs (see Page 87).
1. Turn quill handwheel until it forces tool out of quill.
2. Clean taper and bore, then re-install tool.
1. Adjust gibs (see Page 87).
2. Tighten handwheel fasteners, adjust handwheel
backlash to a minimum (see Page 86).
3. Replace leadscrew mechanism.
1. Remove gibs, clean ways, lubricate, and re-adjust
gibs.
2. Loosen gib screw(s) slightly (see Page 87), and
lubricate bedways.
3. Slightly loosen backlash setting (see Page 86).
4. Lubricate bedways/ball oilers (Page 79).
1. Check for debris, clean, and retighten.
2. Re-install cutting tool so no more than
length is sticking out of tool holder.
3. Adjust gibs (see Page 87).
4. Replace or resharpen cutting tool.
5. Use the recommended spindle speed and feed rate.
1. Re-align tailstock to the headstock spindle
centerline (see Page 41).
1. Remove jaws, clean and lubricate scroll plate, then
replace jaws.
1. Adjust gear levers.
2. Disengage half nut lever.
3. Tighten.
4. Ensure carriage lock bolt is fully released.
5. Frequently clean away chips that load up during
turning operations.
6. Lubricate bedways/ball oilers.
7. Loosen gibs screw(s) slightly (see Page 87).
8. Replace gears.
1. Rotate spindle by hand with light pressure on the
lever until gear falls into place.
Model G0791 (Mfd. Since 9/15)
1
⁄
of the total
3
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