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10. Check for correct operation using the coarse feed
handle. If operating correctly, start the drive motor
and engage the power feed mechanism. Verify that
the power feed lever correctly engages and disengag-
es when driven by the drive motor.
10.6 TABLE LEAD SCREW BACKLASH
ADJUSTMENT
Refer to Figure 24.
The milling machine table is moved by a lead screw and
nut for each machine axis. For proper operation, there
must be clearance between the lead screw and the nut,
which results in backlash. A second lead screw nut is
provided to eliminate most of the backlash. The following
procedures provide instructions for obtaining acceptable
backlash.
Cross Feed Backlash Adjustment:
1.
Use the cross feed crank to move the table to the
extreme rear of its travel.
2.
Remove the pleated way cover.
3.
Open the two chip guards enough to expose the
cross-feed adjustment nut (the nut that is toward the
rear of the nut bracket is not adjustable – only the front
nut is adjustable).
4.
Loosen the two nut locking screws.
5.
Turn the nut slightly to tighten it against the opposing
nut.
Left bearing bracket
Dial
lock
ring
Graduated
dial
Dial holder
Shim(s)
Slots allow adjustment
of thread tightness
Lock Screws
ETM–949 | ETM–949EVS
Table Lead Screw Components
Bearing bracket
Sealed ball
cap screws
bearings
Longitudinal
lead screw nut set
Adjustable
nut
Nut bracket
Bearing
(same part as cross-feed
retaining ring
section view)
Longitudinal feed section view
Threads in bore
accept lead screw
Feed nut - end view
6.
Tighten the two nut locking screws.
7.
Using the cross-feed crank, move the table to the
middle position.
8.
Set up a dial indicator to check cross-feed backlash.
Gently move the cross feed crank back and forth while
watching the dial indicator. Backlash should be be-
tween 0.003 inch and 0.005 inch.
9.
If necessary, repeat the steps above to set backlash.
10. Install the pleated way cover.
Longitudinal Backlash Adjustment:
Refer to Figure 24.
1.
Only one of the longitudinal lead screw nuts can be
adjusted. The other nut is fixed. The left hand nut is
typically adjustable. This can be determined by
looking at the nut from the underside of the table.
2.
Loosen the two nut locking screws.
3.
Turn the nut slightly to tighten it against the opposing
nut.
4.
Tighten the two nut locking screws.
5.
Using the longitudinal table crank, move the table to
the middle position.
6.
Set up a dial indicator to check longitudinal backlash.
Gently move the crank back and forth while watching
the dial indicator. The backlash should be between
0.003 inch and 0.005 inch.
If necessary, repeat the steps above to set backlash.
Right bearing bracket
Rollpin
Leadscrew nut set
Cross-feed section view
Nut bracket
(same part as longitudinal
feed section view)
Bearing retainer ring
Bearing
Bracket
Adjustable
nut
Knee
Casting
Graduated dial
Dial holder
Fig. 24
21
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