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Copyright © 2021 Quality Machine Tools, LLC
PM-1228VF v3 2021-05
Figure 3-25
Power feed enabled
Move the split-nut lever to the right, but NOT as far as it will go — go
to the detent position, no further.
Figure 3-26
Split-nut closed on leadscrew (thread cutting)
Upper
gear
30
30
30
Gear
box
A
B
C
1
0.0008
0.0017
0.0034
2
0.0010
0.0019
0.0038
3
0.0011
0.0022
0.0043
4
0.0013
0.0025
0.0051
5
0.0015
0.0030
0.0061
CROSS-SLIDE FEED
Inches per spindle
revolution
Upper
gear
30
30
30
Gear
box
A
B
C
1
0.0016
0.0032
0.0064
2
0.0018
0.0036
0.0072
3
0.0021
0.0041
0.0082
4
0.0024
0.0048
0.0096
5
0.0029
0.0058
0.0115
SADDLE FEED
Inches per spindle revolution
FEED RATES
These numbers are for
30T as the upper
gear
, the same setup used for cutting many
fine pitch U.S. threads, Figure 3-33. Feed
rates are about 5% slower with the metric
setup, 30T upper gear, Figure 3-35.
FEED RATES FOR NON-THREAD CUTTING OPERATIONS
Figure 3-27
Saddle feed engaged
To select saddle feed, pull the power feed lever toward
you, then twist it to bring the LEFT-RIGHT arrows upper-
most. Swing the lever UP to engage the power feed.
Figure 3-28
Cross-slide feed engaged
To select cross-slide feed, pull the power feed lever toward
you, then twist it to bring the UP-DOWN arrows upper-
most. Swing the lever DOWN to engage the power feed.
ENGAGING THE POWER FEED
Key facts ...
•
If the split-nut lever (apron front) is moved too far to the right,
the apron interlock will not allow you to move the power feed
lever (right, black knob).
• When moving the power feed lever, always test gently for
gear engagement, especially if the motor is off — feel for it,
don’t jam it into gear, jog the cross-slide and/or saddle by
hand if necessary.
• Disengage the power feed by returning the power feed lever
to its center, neutral position.
