Cause |
Solution / Countermeasures |
Scratch or dent in chuck ID and tool
shank |
・Replacement of chuck or tool
・Touching up of area in question（rubbing off with sand
paper ＃1000 and above）
Correction (grinding) by NT TOOL is not possible.
・Ask NT for repair.（In some cases, irrepairable.) |
| Tool shank is too large. |
Use h7 shank tool. |
| Actuating screw is not fully returned
and ID of clamping sleeve was deformed
with residual pressure. |
Insert tool after fully loosening the screw. |
| Notch or flat of tool shank deforms
chuck ID. |
Use a tool without notch or flat and the chuck must be returned
to NT TOOL for repair. |
| Insufficient tool insertion length deforms
deep area of chuck ID. |
・Ask NT for repair. （In some cases, irrepairable.)
・Keep minimum insertion length of tool. |
Cause |
Solution / Countermeasures |
| Insufficient clamping force |
Check clamping function. (No. of revolution of actuating
screw) |
| Insufficient tool insertion length |
Keep minumum insertion length of tool. |
| Tool shank diameter is smaller than h7
tolerance. |
Use h7 shank tool. |
| Cutting resistance (bending moment)
is too large.
（Pull out of tool because of pestle-like
movement.) |
・lower cutting resistance
ａ．Higher rotation or lower feed rate
（Approx. 20%）
ｂ．Lower cutting depth
・Lower bending moment
ｃ．Shoretr tool projection length |
| Insufficient rigidity of holder |
Use different chuck (holder)
Trial of colet holder, milling chuckl or shrinker chuck |
Cause |
Solution / Countermeasures |
| Chattering by chuckr's resonance |
Shift rotation speed to vary resonance frequency.
（± 10％ and above） |
| Insufficient clamping force |
Check clamping function. (No. of revolution of actuating
screw) |
| Insufficient tool insertion length |
Keep minimum insertion length of tool. |
| Tool shank diameter is smaller than h7
tolerance. |
Use h7 shank tool. |
| The amount of cutting is a little, and the slipping phenomenon on the grinding surface by swinging of the blade is generated. |
Revision of cutting conditions (Higher cutting resistance)
ａ．Higher feed rate or lower rotation speed
（Approx. 20%)
ｂ．Higher cutting depth |
| Bending moment is too large. |
・Shorter tool projection length
・Shorter projection length of chuck |
| Inappropriate choice of holder (chuck)
for the cutting (The chuck rigidity is lower than the processing load. ) |
Use different chuck (holder)
Trial of collet holder, milling chuck or shrinker chuck |
| Holder withdrawing power shortage because of defective selection of retention bolt |
Use designated retention stud for the machine. |
| Defect per taper due to swelling of BT shank by tightening retention bolt too much |
Keep recommended torque value for tightening retention
stud |
Cause |
Solution / Countermeasures |
| Rust, scratch or deformation of chuck
I.D. |
・Replacement of chuck or tool
・Touching up of area in question（rubbing off with sand
paper ＃1000 and above）
Correction (grinding) by NT TOOL is not possible.
・Ask NT for repair.（In some cases, irrepairable.) |
| Insufficient chucking length |
Keep minumum insertion length of tool |
| Scratch or dent on tool shank |
Scratch or dent must be removed. |
| Notch or flat of tool shank |
Use a tool without notch or flat. |
| Expansion of BT shank because of
over-tightening retention stud (BT30 in
paticular) |
Keep recommended torque value for tightening retention
stud. |
| Poor accuracy of tool |
Replacement of tools |
| Dust seizing in chucking area |
Cleaning of chuck I.D. |
Deteriorated accuracy of tool interface
・Large runout (2 micrometers and
above) of spindle ID or end face (in
the case of two-face contact)
・ Dust, scratch or dent on taper area
or end face (in the face of two-face
contact) |
・Regrinding or correction of machinespindle
・Cleaning of taper and end face (in the case of two-face
contact), touching up of scratch or dent |
