| General
Problem: Dimensional Accuracy |
| Specific |
Cause |
Solution |
| Oversize
Pitch Diameter |
Incorrect
Tap |
- Use Proper GH limits of taps
- Use longer chamfered taps.
|
| Chip
Packing |
- Use spiral point or spiral fluted taps.
- Reduce number of flutes to provide extra chip room.
- Use larger hole size.
- If tapping a blind hole, allow deeper holes where
applicable or shorten the thread length of the parts.
- Use proper lubricant.
|
| Galling |
- Apply proper surface treatment such as steam oxide
or chrome.
- Use proper cutting lubricant.
- Reduce tapping speed.
- Use proper cutting angle in accordance with material
being tapped.
- Use larger hole size.
|
| Operating
Conditions |
- Apply proper tapping speed.
- Correct alignment of tap and drilled hole.
- Use proper tapping speed to avoid torn or rough threads.
- Use tapping attachment with axial compensation.
- Use proper tapping machine with suitable power.
- Avoid misalignment of the tap and drilled hole from
loose spindle or worn holder.
|
| Tool
Conditions |
- Obtain proper indexing angle for the flutes at
the cutting edge.
- Grind proper cutting angle and chamfer angle.
- Avoid too narrow a land width.
- Remove burrs from regrinding.
|
| Oversize
Internal |
Hole Size |
- Use minimum hole size.
- Avoid tapered hole
- Use proper chamfered taps.
|
| Galling |
Galling solutions
1 through 4 can be applied to this specific problem.
|
| Undersize
Pitch |
Incorrect
Tap |
- Use Oversize taps.
a. Use for cutting materials such as copper alloy,
aluminum alloy and cast iron.
b. Use for cutting tubing which will have "spring
back"
action after tapping.
- Apply proper chamfer angle.
- Increase cutting angle.
|
| Damaged Thread |
- Use proper reversing speed to avoid damaging tapped
thread on the way out of the hole.
|
| Leftover Chips |
- Increase cutting performance to avoid any left
over chips in the hole.
|
| Undersize
Internal Diameter |
Hole Size |
- Use maximum drill size
|
| General
Problem: Surface Finish |
| Specific |
Cause |
Solution |
| Torn
or Rough Thread |
Chamfer Too
Short |
- Increase chamfer length.
|
| Wrong Cutting
Angle |
- Apply proper cutting angle.
|
| Galling |
- Use thread relieved taps.
- Reduce land width.
- Apply surface treatment such as steam oxide or chrome.
- Use proper cutting lubricant.
- Reduce tapping speed.
- Use larger hole size.
- Obtain proper alignment between tap and work.
|
| Chip Packing |
- Use spiral pointed or spiral fluted taps.
- Use larger drill size.
|
| Tool Condition |
- Avoid too narrow a land width.
- Do not grind the bottom of the flute.
|
| Chattering
on Tapped Thread |
Tool Free
Cutting |
- Reduce cutting angle.
- Reduce amount of thread relief.
|
| General
Problem: Tool Life |
| Specific |
Cause |
Solution |
| Breakage |
Incorrect
Tap Selection |
- Avoid chip packing in the flutes or the bottom
of the hole. Use spiral pointed or spiral fluted
taps or fluteless taps.
- Apply correct surface treatment such as steam oxide
or bright.
|
| Excessive
Tapping Torque |
- Use larger drill size.
- Try to shorten thread length.
- Increase cutting angle.
- Apply a tap with more thread relief and reduced land
width.
- Use spiral pointed or spiral fluted taps.
|
| Operating
Condition |
- Reduce tapping speed.
- Avoid misalignment between tap and the hole and tapered
hole.
- Use floating type of tapping holder.
- Use tapping holder with torque adjustment.
- Avoid hitting bottom of the hole with tap.
|
| Tool Condition |
- Do not grind bottom of the flute.
- Avoid too narrow a land width.
- Remove all worn sections when regrinding the flutes.
- Regrind tool more frequently.
|
| Chipping |
Incorrect
Tap Selection |
- Reduce cutting angle.
- Use a different kind of high speed steel tap.
- Reduce hardness of the tap.
- Increase chamfer length.
- Avoid chip packing in the flutes or in the bottom
of the hole by using spiral fluted or spiral pointed
taps.
|
| Operating
Conditions |
- Reduce tapping speed.
- Avoid misalignment between tap and hole.
- Avoid sudden return of reverse in blind hole tapping.
- Avoid galling.
- Use larger hole size.
|
| Wear |
Incorrect
Tap Selection |
- Apply specially designed taps for tapping heat
treated material.
- Change to a type of high speed steel tap that contains
vanadium.
- Apply special surface treatment such as nitriding.
- Increase chamfer length.
|
| Operating
Conditions |
- Reduce tapping speed.
- Apply proper cutting lubricants.
- Avoid work hardened hole.
- Use larger hole size.
|
| Tool Condition |
- Grind proper cutting angle.
- Avoid hardness reduction from grinding process.
|
| General
Problems Related To Tap Holder |
| Specific |
Cause |
Solution |
| Tap
stops before reaching required depth |
Clutch of
X, R or TC/DC is slipping with new tap. |
- Increase torque adjustment until a sharp tap can
be driven to proper depth. Then add one half turn
and lock adjustment
|
| Clutch of
X, R or TC/DC is slipping with dull tap. |
- Change to new sharp tap.
|
| Clutch of
X, R or TC/DC slips when fully tightened. |
- The torque required is too great for the tapping
attachment. Use a larger model.
- Clutch may be worn and needs replacing.
|
| The housing
of the X, R or TC/DC stops rotating. |
- The torque required is too great for the machine
and the machine spindle is stopping. A machine with
more torque is needed.
|
| Drive disengages
and goes into neutral. |
- Set machine stop to allow tap to feed deeper into
hole.
|
| The self-feed
adjustment of TC/DC is set to minimum self-feed and drive
goes into neutral. |
- Back off self-feed adjustment for more forward
drive engagement and adjust machine stop.
- Note: There can be confusion between the clutch slipping
and the drive going into neutral. You can determine
what is occuring from the sound. With the R model,
there is a loud ratcheting sound when the clutch slips.
When the drive goes into neutral it is quiet. With
the X or TC/DC model when the clutch slips there is
no sound and when the drive goes into neutral there
is a clicking sound.
|
| Tap
pulls out of collet chuck. |
Tap chuck
nut is not tightened securely. |
- Be sure to follow operator instructions for installation
of tap.
|
| Tap square
is not being driven properly. |
- Be sure to follow operator instructions for installation
of tap.
|
| Back jaws
for driving tap square are damaged. |
- Replace back jaws and please see operator instructions
for installation of tap.
|
| Tap stops
and starts chattering on the way out of the hole. |
With X, R
or TC/DC speed increases by 1.75 times for reverse, operator
is not feeding fast enough to keep up with tap. |
- Retract the machine spindle at a faster rate with
a smooth motion.
|
| Tap stops
and starts chattering on the way out of the hole. |
With RDT,
ID or NCRT on a machining center, the feed rate is not
keeping up with the tap. |
- Adjust machines feed rate correctly according to
operator instructions.
- Be sure that potentiometer over ride control is canceled.
Please see programming in operator instructions.
- Be sure that "Ramp" or "Exact Stop"
is not in effect. Please see programming in operator
instructions.
|
| Self-reversing
tapping attachment does not reverse. |
Stop arm is
not installed or prevented from rotating. |
- Please see operator instructions for stop arm and
torque bar installation.
|
| Coolant
has entered the housing of the tapping attachment. |
Tapping attachment
is being flooded with external coolant. |
- Try to avoid flooding tapping attachment itself.
|
| Internal Coolant
system is leaking due to pressure build up. |
- Please be sure not to exceed maximum recommended
pressure. Please be sure outlet for coolant flow
is adequate. Please see operator instructions.
|
Note:
Coolant can be removed by using the following procedure.
|
