Granite Troubleshooting

Powerfeed and Thread Cutting
1. Powerfeed does not move carriage
Problem	Solution
• Carriage locked	• Unlock carriage
• Speed selector not engaged	• Select speed I or II or III,   engage drive selector
• Sheared pin	• Replace pin
• Gears not meshing   or teeth missing	• Check gears and adjust
• Inch/metric lever in neutral	• Engage fully
2. Cut is not smooth
Problem	Solution
• Tool dull	• Sharpen or replace tool
• Tool not on center	• Center tool   (shim, if needed)
• Tools not mounted tightly in post	• Remount tools
• Cross-slide gibs to bed   and base loose	• Adjust gibs
• Gibs in toolpost loose	• Adjust gibs in toolpost
• Tool turret not tight	• Tighten toolpost
• Feed rate too fast	• Choose correct setting
• Gear loose	• Tighten gears and posts
3. Thread is not smooth
Problem	Solution
• Tool dull	• Sharpen tool
• Tool not centered	• Center tool
• Tools not mounted tight in post	• Remount tool
• Cross-slide gibs to bed   and base loose	• Adjust gibs
• Gibs in compound loose	• Adjust gibs
• Tool turret not tight	• Tighten toolpost
• Gears loose	• Tighten gears and posts
4. Tools is not cutting “on thread”
Problem	Solution
• Powerfeed slipping	• Engage halfnut fully
• Clutch slipping	• Tighten screws (6)
Carriage/Milling Table
1. Table won't move
Problem	Solution
• Table locks engaged	• Loosen locks
• Gibs too tight	• Loosen gibs
2. Horizontal and vertical movement     in cross-slide table
Problem	Solution
• Carriage gib improperly adjusted	• Adjust carriage gib
• Table gib improperly adjusted	• Adjust table gib
3. Carriage moves smoothly in only     one direction
Problem	Solution
• Debris on way or gib	• Remove debris
• Burr on gib	• Remove burr with fine file
• Gib improperly tensioned	• Loosen gib and re-tension
• One or more wipers mounted too low	• Reposition wiper(s)
4. Cross slide handwheel turns     during cutting operations
Problem	Solution
• Cross-slide brass nut worn	• Tighten or replace brass nut
• Carriage lock not tight	• Tighten carrriage locks
• Gibs too loose	• Readjust gibs
5. Too much backlash in the cross-slide
Problem	Solution
• Loose screw	• Tighten screw, review how to   eliminate backlash
• Loose brass nut	• Put a shim between the   stud on the nut and the   side of the hole
• Worn brass nut	• Replace brass nut or adjust   screw at end of nut
• Excessive space between bearing	• Add shim washer and dial
Lathe Turning
Problem	Solution
• Tool dull	• Sharpen or replace tool
• Tool not ground properly	• Regrind tool
• Tool at wrong angle	• Correct tool position
• Tools not held tightly	• Tighten toolholder
• Wrong cutter for material	• Use correct cutter
• Cutting speed incorrect	• Increase or reduce speed
2. Work has unwanted taper
Problem	Solution
• Work improperly aligned	• Realign centers on work
• Debris in spindle, setup, or tools	• Clean and reset setup,   work, or  tool
• Offset tailstock incorrectly positioned	• Correct position  of tailstock
• Spindle bearings loose	• Tighten taper bearings    to return to alignment,    replace spindle bearings
3. Machine vibrates
Problem	Solution
• Work mounted wrong	• Remount work
• Speed too high	• Reduce Speed
• Too much pressure at tailstock	• Reduce pressure and   increase lubrication
4. Work stops turning but machine     continues to run
Problem	Solution
• Work not mounted securely	• Remount work
• Tools forced into   work/ excessive cut	• Reduce force on tools
• Belts slipping	• Tension belts, use belt   dressing, or replace belts
5. Diameter of work is not consistent
Problem	Solution
• Too much flex in workpiece	• Use a follow rest,   use tailstock center
• Too much flex compound rest,   cross slide, or carriage	• Tighten gibs, clean ways
6. Too much backlash in the compound
Problem	Solution
• Loose spanner nuts   • Worn Nut	• Tighten spanner nuts • Replace nut
7. Machine slings oil from behind     the chuck or in belt box
Problem	Solution
• Oil reservior overfilled	• Check oil lever
• Worn oil  seal	• Replace felt in seal
Milling
1. Tool chatter
Problem	Solution
• Gibs too loose on cross   slide, compound, or carriage	• Readjust gibs
• Unused feeds not locked	• Lock all axes but the one   moving
• Millhead not locked	• Lock millhead
• Quill too loose	• Tighten quill lock
• Tool not on center	• Center tool
• Improper tool shape, tool dull	• Reshape, sharpen, or replace   tool
• Feed too light or slow	• Adjust feed rate
2. Depth of cut is not consistent
Problem	Solution
• Quill moving	• Lock quill
• Setup wrong	• Make sure setup is parallel to   table
Drilling
1. Hole is off center or bit wanders
Problem	Solution
• Bit dull	• Use sharp bits
• Bit not mounted correctly in chuck	• Remount tool
• Bit bent	• Replace bit
• Chuck loose in spindle	• Remount chuck on arbor
• Drawbar not secured	• Tighten drawbar
• Debris on spindle	• Clean debris and arbor   and remount tool
• Bearing loose or worn	• Tighten or replace bearings
• Cutting too fast	• Reduce speeed
• Incorrect bit	• Use correct bits
• No pilot hole	• Drill small pilot hole
2. Entrance hole is out of round
Problem	Solution
• Bit dull     • Incorrect drill bit	• Use sharp bit • Use correct drill bit
3. Bit turns erratically or stops
Problem	Solution
• Bit fed into work too fast	• Reduce feed rate
• Belts slipping	• Reduce feed rate, retension   belts
4. Chuck is difficult to tighten or loosen
Problem	Solution
• Chuck sticking	• Apply lubricant
• Debris in chuck	• Clean chuck
5. Chuck wobbles
Problem	Solution
• Chuck loose on arbor	• Clean arbor and remount
• Drawbar not tight	• Clean spindle and replace drawbar
Drive System
1. Turn on the machine and     nothing happens
Problem	Solution
• Breaker Blown	• Reset circuit breaker
• Machine unplugged	• Plug in the machine
• Loose electrical connections	• Tighten wiring connections
• Electrical components bad	• Replace defective parts
2. Motor and pulleys turn,     but not lathe or mill
Problem	Solution
• Mill or lathe not selected	• Select proper function