Duff-Norton NZ-100 - Manual (Page 7)

4-5. Ball Nut Removal
backlash. Push back and forth on the nut,
without rotation. Movement should be no
more than shown in Table 1. Use a dial
indicator if available.
It is not uncommon for nuts to exhibit wear
before any damage to the screw. If this is
the case, a new nut can be fitted without
screw replacement.
Other than the lubrication described in the previous
section, regular maintenance should not be
required. If disassembly is required to repair
damage or a failure, the following procedure may
be followed.
4-1. Disassembly
(Refer to Figure 5-1)
4-2. Screw & Tube Disassembly
4-3. Screw Removal
4-4. Screw and Nut Inspection
SECTION IV
MAINTENANCE
7
Do not disassemble ball nut from
tube unless ball nut inspection or
repair is necessary.
Note
Remove SuperCylinder from installation
and move to a work area.
Remove limit switch (if fitted).
Loosen two setscrews on outer tube.
Unscrew tube and pull off. Clean excess
grease from screw and tube.
Remove the metric socket head screws
holding the trunnion housing to the
gearbox, and separate the housings.
1.
2.
3.
4.
Spread and remove nylon nut guide from
inner end of translating tube.
Loosen two setscrews holding lifting nut.
These are installed with thread locking
adhesive and may require heating.
Clamp lifting nut in vise. Insert bar in clevis
hole and unscrew translating tube.
1.
2.
3.
1.
2.
3.
1.
2.
Remove the two pipe plugs from the
trunnion housing.
Use a long pin punch to drive grooved pin
out of the screw (note direction of groove
taper). Support screw to avoid bearing
damage.
Remove slotted nut and withdraw screw.
Clean excess grease from the screw and
nut. Inspect the screw thread areas for any
wear, pitting, gouges, spalling, brinelling,
or corrosion. Any deterioration of the
thread contact surfaces is cause for
replacement.
If screw is undamaged, clamp it in a vise
with soft jaws and check the nut for
3.
1.0” .008”
1.17-2.50” .025”
3.0” .050”
Max
Screw O.D Backlash
Table 1
Removal of a ball nut from the screw
is not recommended unless there is a
reason to do so.
Note
Clamp screw in vise with soft jaws and use
an impact wrench to loosen the stop
washer bolt in the end of the screw. This
bolt is installed with high strength locking
adhesive. The use of heat is
recommended.
Ball screw nuts, if already determined to
need replacement, can be screwed off,
with balls being lost as it comes off the
screw.
If ball nuts are to be reused, it is
recommended that an arbor be made for
capturing balls. This will eliminate the need
to reload balls. The arbor can be made
from any stiff material and should be about
2" longer than the ball nut. A piece of
tubular material is easier to secure inside
the nut, but a solid bar can be used. Arbor
diameters are given in Table 2.
Hold arbor tight against and centered with
the end of the screw (a pilot to engage in
the screw hole is helpful). Turn the nut
down the screw and continue running it
over the arbor until it is completely off the
screw.
Use wire, tape, cable ties, or similar to
prevent the arbor from falling through the
nut.
1.
2.
3.
4.
5.
1.17” .88”
1.5” 1.156”
2.25” 1.88”
3.0” 2.50”
Arbor
Screw O.D Dia.
Table 2