What Is The Common Problem in A Lathe Machine

(1). Foot brake is engaged.

Check to see that foot brake is up.

(2). Emergency stop push-button is engaged/ faulty.

Rotate clockwise slightly until it pops out/replace it.

(3). Power supply is at fault/switched OFF.

Power supply is switched ON.

(4). Fuse has blown.

Correct short/replace fuse in main electrical box.

(5). Plug/receptacle is at fault or wired incorrectly.

Test for good contacts, correct the wiring.

(6). Start capacitor is at fault.

Test/replace if faulty.

(7). Motor connection wired incorrectly.

Correct motor wiring connections.

(8). Thermal overload relay has tripped.

Turn cut-out dial to increase working amps and push

the reset pin. Replace if tripped multiple times (weak relay).

(9). Contactor not getting energized/has burnt contacts.

Test for power on all legs and contactor operation.

Replace unit if faulty.

(10). Wall fuse/circuit breaker is blown/tripped.

Ensure correct size for machine load; replace weak breaker.

(11). Motor ON button or ON/OFF switch is at fault.

Replace faulty ON button or ON/OFF switch.

(12). Wiring is open/has high resistance.

Check for broken wires or disconnected/corroded

connections, and repair/replace as necessary.

(13). Motor is at fault.

Test/repair/replace.

(14). Spindle rotation switch is at fault.

Turn switch to FWD/REV; replace bad switch.

(15). Foot brake safety switch is faulty.

Test, replace if needed.

(1). Oil level in headstock is too low or too high

Check the oil level and replenish or discharge the oil to the   proper level

(2). Quality and viscosity of oil is wrong

Replace the oil with recommended one .

(3). Oil is too dirty .

Replace oil .

(4). Oil hole in bearing obstructed by dirt .

Remove the dirt from the oil hole .

(5). Bearing obstructed by dirt .

Clean the bearing and renew oil .

(6). Badly worn bearing.

Replace bearing .

(7). Bearing in its case is not improper position .

Dismantle and reassemble it .

(8). Bent or sprung main spindle .

Replace main spindle .

(9). Too much end thrust .

Adjust thrust nut .

(1). Plug of drain not tightly.

Remove recement threat, replace and tighten

(2). Headstock Cracking

Repaired by special welding

(3). Leakage from overflow headstock cover

Tighten cover screw or replace gasket

(4). Leakage from overflow spindle bearing house

Replace oil ring

(1). Pulley setscrews or keys are missing or loose

Inspect keys and setscrews. Replace or tighten if necessary

(2). Motor fan is hitting the cover.

Tighten fan or shim cover, or replace items.

(1). Motor overloaded.

Reduce load on motor.

(2). Air circulation through the motor restricted.

Clean out motor to provide normal air circulation.

(1). Excessive depth of cut or feed rate.

Decrease depth of cut or feed rate.

(2). RPM or feed rate wrong for cutting operation.

Refer to RPM feed rate chart for appropriate rates.

(3). Cutting tool is dull.

Sharpen or replace the cutting tool.

(4). Gear setup is too tight, causing them to bind.

Re-adjust the gear setup with a small amount of

backlash so the gears move freely and smoothly

when the chuck is rotated by hand.

(1). Badly worn Bearing .

Replace Bearing

(2). Badly worn Gear

Replace Gear

(3). Bent or sprung Shaft .

Replace Shaft .

(4). Lose of foundation Bolts .

Tight foundation Bolts

(1). Workpiece is   unbalanced.

Reinstall workpiece so it   is as centered with the

spindle bore as possible.

(2). Loose or damaged   belts.

Tighten/replace the belt   as necessary.

(3). V-belt pulleys are   not properly aligned.

Align the V-belt pulleys.

(4). Worn or broken gear   present.

Inspect gears and replace   if necessary.

(5). Chuck or faceplate   has become unbalanced.

Rebalance chuck or   faceplate; contact a local

machine shop for help.

(6). Spindle bearings   badly worn.

Replace spindle bearings.

(1). Wrong RPM or feed   rate.

Adjust for appropriate   RPM and feed rate.

(2). Dull tooling or poor   tool selection.

Sharpen tooling or select   a better tool for the intended operation.

(3). Too much play in   gibs.

Tighten gibs.

(4). Tool too high.

Lower the tool position.

(1). Quill had not retracted all the way back into the tailstock.

Turn the quill handwheel until it forces taper out of quill.

(2). Debris was not removed from taper before inserting into   quill.

Always make sure that taper surfaces are clean.

(1). Gibs are out of adjustment.

Tighten gib screws

(2). Handwheel is loose.

Tighten handwheel fasteners.

(3). Mechanism worn or out of adjustment.

Tighten any loose fasteners on lead screw mechanism.

(1). Gibs are loaded up with shavings, dust, or grime.

Remove gibs, clean ways/dovetails, lubricate, and readjust gibs.

(2). Gib screws are too tight.

Loosen gib screw(s) slightly, and lubricate Bed-ways.

(3). Backlash setting too tight (cross slide only).

Slightly loosen backlash setting by loosening the locking screw and adjusting the spanner ring at the end of the handle.

(4). Bed-ways are dry.

Lubricate bed-ways and handles.

(1). Clamp of work piece in from loose status.

Tighten clamp

(2). Spindle bearing thrust too loose

Adjust bearing thrust

(3). Headstock is not tight with bed-way

Tighten headstock screw

(4). Excess clearance between carriage and bed-way

Adjust carriage back clamp

(5). Excess clearance in cross or compound slide

Adjust taper gib

(6). Cutting angle of cutting tool is not correct

Regrind tools to correct cutting angles

(7). Edge of cutting tool has been worn - out

Re-grind cutting tool

(8). Weak of tool shank and too long for extension

Replace with rigid tools or reset the tools

(9). Tools fixed to holder not tight enough

Tighten tools again

(10). Unbalances of workpiece or chuck when high speed revolution

Balance or reduce spindle speed revolution

(11). Front point of cutting tool not in correct position .

Re-set Cutting Tool

(1). Tool holder not tight enough.

Check for debris, clean, and retighten.

(2). Cutting tool sticks too far out of tool holder, lack of support.

Reinstall cutting tool so no more than 1/3 of the total length is sticking out of tool holder.

(3). Gibs are out of adjustment.

Tighten gib screws at affected component.

(4). Dull cutting tool.

Replace or resharpen cutting tool.

(5). Incorrect spindle speed or feed rate.

Use the recommended spindle speed.

(1). Headstock and tailstock are not properly aligned with each   other.

Re-align the tailstock to the headstock spindle bore center line.

(1). Chips lodged in the jaws.

Remove jaws, clean and lubricate chuck threads, and replace jaws.

(1). Gears are not all engaged.

Adjust gear positions.

(2). Gears are broken.

Replace.

(3). Loose screw on the feed handle.

Tighten.

(1). Carriage lock is tightened down.

Check to make sure the carriage lock bolt is fully released

(2). Chips have loaded up on bed-ways.

Frequently clean away chips that load up during turning operations

(3). Bed-ways are dry and in need of lubrication.

Lubricate bed-ways and handles.

(4). Longitudinal stops are interfering.

Check to make sure that stops are floating and not hitting the center stop.

(5). Gibs are too tight.

Loosen gib screws slightly.

(1). Feed valve is too Large

Reduce feed valve size

(2). Workpiece is too Thin or too Long

Use supporting rest and adjust position of tool

(1). Gears not aligned in the headstock.

Rotate spindle by hand until gear falls into place

(1). Gears not aligned in headstock or no backlash.

Adjust gears and establish backlash.

(2). Broken gear or bad bearing.

Replace broken gear or bearing.

(3). Workpiece is hitting stationary object.

Stop lathe immediately and correct interference problem.

(1). Excessive clearance   of lead screw in axial direction

Adjust the thrust nut of   the lead screw holder

(2). Excessive clearance   between saddle and cross slide or cross slide and tool post slide

Adjust slide gib to   proper position

(3). Worm thread or nut in cross slide or tool post slide

Adjust or replace it

(4). Excessive clearance of Hand-wheel

Adjust the set bushing of Hand–wheel

(1). Quill lock knob is tightened down.

Turn knob counterclockwise.

(1). Incorrect position of cam .

Adjust cam and lock in proper position .