Problem |
Solution |
Oversize
Pitch Diameter |
Incorrect
tap |
1.
Use proper GH limits of taps. |
|
2.
Use longer chamfered taps |
|
Chip
packing |
1.
Use spiral point or spiral fluted taps. |
|
2.
Reduce number of flutes to provide extra chip room. |
|
3.
Use larger hole size. |
|
4.
If tapping a blind hole, allow deeper holes where applicable or shorten
the thread length of the parts. |
|
5.
Use proper lubricant. |
|
Galling |
1.
Apply proper surface treatment such as steam oxide or TiN. |
|
2.
Use proper cutting lubricant. |
|
3.
Reduce tapping speed. |
|
4.
Use proper cutting angle in accordance with material being tapped. |
|
5.
Use larger hole size. |
|
Operating
conditions |
1.
Apply proper tapping speed. |
|
2.
Correct alignment of tap and drilled hole. |
|
3.
Use proper tapping speed to avoid torn or rough threads. |
|
4.
Use lead screw tapper. |
|
5.
Use proper tapping machine with suitable power. |
|
6.
Avoid misalignment of the tap and drilled hole from loose spindle or worn
holder. |
|
Tool
conditions |
1.
Obtain proper indexing angle for the flutes at the cutting edge. |
|
2.
Grind proper cutting angle and chamfer angle. |
|
3.
Avoid too narrow a land width. |
|
4.
Remove burrs from regrinding. |
|
Problem |
Solution |
Oversize
Internal Diameter |
Hole
size |
1.
Use minimum hole size. |
|
2.
Avoid tapered hole. |
|
3.
Use proper chamfered taps. |
|
Galling |
1.
Apply proper surface treatment such as steam oxide or TiN. |
|
2.
Use proper cutting lubricant. |
|
3.
Reduce tapping speed. |
|
4.
Use proper cutting angle in accordance with material being tapped. |
|
Problem |
Solution |
Undersize
Pitch Diameter |
Incorrect
tap |
1.
Use oversize taps for cutting materials such as copper alloy, aluminum
alloy, and cast iron. |
|
2.
Use oversize taps for cutting tubing which will have "spring
back" action after tapping. |
|
3.
Apply proper chamfer angle. |
|
4.
Increase cutting angle. |
|
Damaged
thread |
Use
proper reversing speed to avoid damaging tapped thread on the way out of
the hole. |
|
Left-over
chips |
1. Increase cutting performance to avoid any left over chips in the hole. |
|
2. Remove left over chips from the hole for
gage checking. |
|
Problem |
Solution |
Undersize
Internal Diameter |
Hole
diameter |
Use
maximum drill size. |
|
Problem |
Solution |
Torn
/ Rough Thread |
Chamfer
too short |
Increase
chamfer length. |
|
Wrong
cutting angle |
Apply
proper cutting angle. |
|
Galling |
1.
Use thread relieved taps. |
|
2.
Reduce land width. |
|
3.
Apply surface treatment such as steam oxide or TiN. |
|
4.
Use proper cutting lubricant. |
|
5.
Reduce tapping speed. |
|
6.
Use larger hole size. |
|
7.
Obtain proper alignment between tap and work. |
|
Chip
packing |
1.
Use spiral pointed or spiral fluted taps. |
|
2.
Use larger drill size. |
|
Problem |
Solution |
Chattering
on Tapped Thread |
Too
free cutting |
1.
Reduce cutting angle. |
|
2.
Reduce amount of thread relief. |
|
Tool
conditions |
1.
Avoid too narrow a land. |
|
2.
Do not grind the bottom of the flute. |
|
Problem |
Solution |
Breakage |
Incorrect
tap selection |
1.
Avoid chip packing in the flutes or the bottom of the hole. Use spiral
pointed or spiral fluted taps or fluteless taps. |
|
2.
Apply correct surface treatment such as steam oxide or TiN. |
|
Excessive
tapping torque |
1.
Use larger drill size. |
|
2.
Try to shorten thread length. |
|
3.
Increase cutting angle. |
|
4.
Use a tap with more thread relief and reduced land width. |
|
5.
Use spiral pointed or spiral fluted taps. |
|
Operating
conditions |
1.
Reduce tapping speed. |
|
2.
Avoid misalignment between tap and the hole and tapered hole. |
|
3.
Use floating type of tapping holder. |
|
4.
Use tapping holder with torque adjustment. |
|
5.
Avoid hitting bottom of the hole with tap. |
|
Tool
conditions |
1.
Do not grind the bottom of the flute. |
|
2.
Avoid too narrow a land width. |
|
3.
Remove all worn sections when regrinding the flutes. |
|
4.
Regrind tool more frequently. |
|
Problem |
Solution |
Chipping |
Incorrect
tap selection |
1.
Reduce cutting angle. |
|
2.
Use different kind of high-speed steel tap. |
|
3.
Reduce hardness of the tap. |
|
4.
Increase chamfer length. |
|
5.
Avoid chip packing in the flutes or in the bottom of the hole by using
spiral fluted or spiral pointed taps. |
|
Operating
conditions |
1.
Reduce tapping speed. |
|
2.
Avoid misalignment between tap and hole. |
|
3.
Avoid sudden return of reverse in blind hole tapping. |
|
4.
Avoid galling. |
|
5.
Use large hole size. |
|
Problem |
Solution |
Wear |
Incorrect
tap selection |
1.
Use specially designed taps for tapping heat treated material. |
|
2.
Change to a type of high-speed steel tap that contains vanadium. |
|
3.
Apply special surface treatment such as steam oxide or TiN. |
|
4.
Increase chamfer length. |
|
Operating
conditions |
1.
Reduce tapping speed. |
|
2.
Apply proper cutting lubricants. |
|
3.
Avoid work hardening. |
|
4.
Use larger hole size. |
|
Tool
conditions |
1.
Grind proper cutting angle. |
|
2.
Avoid hardness reduction from grinding process. |