INSTALLING
SEL, SAR, AND SAG BALL NUTS
These nuts must be transferred from the
arbor to the screw without preload. Be sure to keep the ball return
tubes aligned with each other and make sure the coupling tangs line
up with the slots in the ball nut.
Center the adjusting nut on the coupling.
Before preloading these ball nuts, all the coupling threads, spring
washers/spacers and ball grooves should be lubricated.
Position the ball nut on the center of the
screw shaft. It is a good idea to place retainers (tape, tie-straps,
etc.) on the screw to prevent the ball nut from over-traveling.
With the ball return tubes facing upward, tighten the adjusting
nut against the spring washer or spacer by hand until it cannot
be turned. While holding the ball nut with tubes facing up, rotate
the screw several turns in both directions.
Running torque can be measured by means of
a spring scale. The force reading multiplied by the lever arm length
yields the running torque value.
Make adjustments to achieve desired preload
and recheck running torque value up and down the screw shaft. Do
not tighten the adjusting nut to a point that fully collapses the
spring washers. After the system is adjusted, secure the adjusting
nut with the set screws provided.
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