Tapping Faults/Causes Chart

Fault Codes

O = OVERSIZED OR BELL-MOUTHED TAPPED HOLES
P = POOR FINISH THREADS
T = TAP TEETH CHIPPING
E = EXCESSIVE RATE OF WEAR ON TAP
B = BROKEN TAP
C = COLD WELDING OR GALLING

Faults and Causes

Cause Fault Codes
MISALIGNMENT O-P-T
TAP LEAD REGROUND OR ECCENTRIC O
INCORRECT FEED RATE O-P
WRONG TYPE OF TAP FOR JOB O-P-E-B
BLUNT TAP P-E-B-C
INCORRECT SHARPENING OF TAP O-P-T-E-B-C
LACK OF OR INCORRECT LUBRICANT O-P-E-B-C
TAP HITTING BOTTOM OF HOLE T-B
TAP SPEED TOO HIGH E-B-C
WORK HARDENED SKIN IN DRILL HOLE E-B
MACHINE REQUIRES OVERHAUL O-P-T-B
CHIPS NOT BEING REMOVED PROPERLY P-B
TAP DRILL SIZE INCORRECT O-B
MATERIAL TOO SOFT C
INCORRECT MATERIAL STRUCTURE C