| PROBLEM |
CAUSES |
SOLUTION |
| Oversize Pitch Diameter |
Incorrect Tap |
1. Use proper pitch diameter limits of taps. If it is
oversize to regrinding ,to make more hook or less width
of land.
2. Use longer chamfered taps. |
| Chip Packing |
1. Use spiral point £¨short hole£İor
spiral fluted taps£¨longer hole or blind hole£İ.
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 correct power of machine.
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. Remove burrs from regrinding. |
| Oversize Minor Diameter |
Hole Size |
1. Use minimum hole size.
2. Avoid tapered hole or bell-mouth.
3. Use proper chamfered taps. |
| Galling |
1. Apply surface treatment such as
steam oxide or TiN.
2. Use proper cutting lubricant.
3. Reduce tapping speed.
4.According to the materials,choose proper tap rake. |
| Undersize
Pitch Diameter |
Incorrect
Tap |
1. Use oversize taps:
ĦĦa. Use for cutting materials such as copper alloy, ĦĦĦĦaluminum
alloy, and cast iron.
ĦĦb. Use for cutting tubing which will have "spring
back" ĦĦĦĦaction after tapping.
2. Check pitch diameter of the tap.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.
|
| Undersize Minor Diameter |
Hole Size |
Use maximum drill size. |
