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Copyright © 2021 Quality Machine Tools, LLC
PM-1340GT v8 2021-04
CUTTING METRIC THREADS
For metric thread cutting the split-nut on the apron must
be left
engaged throughout the entire process
. This
not the case for U.S. standard TPI threads, for which the
normal procedure is to disengage the half-nut after each
METRIC PITCH (mm)
mm
6
4.8
4
Gearbox
A1
A4
A6
mm
3
2.4
2
Gearbox
B1
B4
B6
mm
1.5
1.2
1
Gearbox
C1
C4
C6
mm
0.75
0.6
0.5
Gearbox
D1
D4
D6
mm
0.3
0.25
Gearbox
E4
E6
METRIC PITCH (mm)
mm
7.5
6
5
Gearbox
A1
A4
A6
mm
3.75
3
2.5
Gearbox
B1
B4
B6
mm
1.5
1.25
Gearbox
C4
C6
mm
0.75
Gearbox
D4
METRIC PITCH (mm)
mm
4.5
4
3
Gearbox
A1
A2
A6
mm
2.25
2
1.8
1.5
Gearbox
B1
B2
B4
B6
mm
1
0.9
0.75
Gearbox
C2
C4
C6
mm
0.5
0.45
Gearbox
D2
D4
mm
0.25
Gearbox
E2
Figure 3-18
Metric thread cutting tables
pass, reverse the carriage, then re-engage at a specif-
ic indication on the threading dial (see above).
NOTE
:
For metric threads the lower of the two external change
gears is driven by the inner (120T) transposing gear.
