PROBLEM SOLVING GUIDE
AVOID PROBLEMS BY CAREFUL ORIGINAL SET-UP
MACHINE CONDITION Tool holder in good condition and secure part holding fixture
TOOL CONDITION Use cutting tool recommended for material being machined. Avoid excessive tool overhang.
FEEDS & SPEEDS Start with feeds and speeds recommended for material being machined
COOLANT Coolant flow must be adequate to avoid intermittent quenching and to flush chips promptly, avoiding the recutting of hardened chips.
REAMING PROBLEMS POSSIBLE CAUSES POSSIBLE SOLUTIONS
1. POOR FINISH Unequal chamfers Regrind reamer with equal chamfer height
Incorrect margins Regrind reamer with narrower margins for reaming higher tensile materials
Excessive spindle runout Use bushing - .0002"/.0003" over reamer diameter
Chatter Increase speed and reduce feed rate
Use power feed unless material is hard
Use spiral fluted reamer
Grind secondary lead angle immediately behind 45º chamfer
Insufficient cutting action Specify reamer with positive radial rake to reduce cutting preasure - may
produce slightly larger diameter holes
2. OVERSIZED HOLES
TAPERED HOLES
BELL MOUTH HOLES 		Misalignment Check fixturing & setup for possible causes; use floating holder if necessary
Consider using precision bushings or piloted reamers
Incorrect feed and/or speed Verify feeds & speeds
3. EXCESSIVE TOOL WEAR Improper stock removal Change pre-ream hole size to leave 2 to 3% of tool diameter
Excessive reaming pressure Decrease feed rate
See solution for "improper stock removal" in #3
Misalignment See solution for "misalignment" in #2
4. CROOKED HOLES Drill walking or incorrect sharpening Correct drilling operation - reamer will follow drilled hole
Increase 90º included chamfer angle to 120º - 180º
5. TOOL BREAKAGE Excessive reaming pressure See solution for "excessive reaming pressure" in #3
Misalignment See solution for "misalignment" in #2