Southbend 13" Heavy 13 Gearhead lathe SB - Manual (Page 79)

For Machines Mfg. Since 5/11 13" Heavy 13 ® Gearhead Lathe
-77-
S E R V I C E
Half Nut Adjustment
The clamping pressure of the half nut is fully
adjustable with a gib that can be loosened or
tightened by two set screws. Use this procedure
to adjust the half nut if it becomes loose from
wear, or it is too tight for your preferences. A
half nut that is too loose will make it difficult
to produce accurate work. A half nut that is too
tight will increase the rate of wear on itself and
the leadscrew.
Tool Needed: Qty
Hex Wrench 3mm ................................................. 1
To adjust the half nut:
1. Disengage the half nut, then remove the
thread dial.
2. Turn the two set screws (see Figure 121)
clockwise to tighten the half nut and
counterclockwise to loosen it.
Note: Make sure to turn the set screws in even
amounts so that one end of the gib does not
become tighter than the other.
3. Engage/disengage the half nut several times
and notice how it feels. The half nut is
correctly adjusted when it has a slight drag
while opening and closing. The movement
should not be too stiff or too sloppy.
4. Repeat Steps 2–3, if necessary, until you are
satisfied with the half nut pressure.
5. Re-install the thread dial.
Figure 121. Half nut gib adjustment.
Set
Screws
V-Belts
V-belts stretch and wear with use, so check the
tension on a monthly basis to ensure optimal
power transmission. Replace all of the V-belts
as a matched set if any of them show signs of
glazing, fraying, or cracking.
Tools Needed: Qty
Phillips Screwdriver #2 ........................................ 1
Open End Wrench 24mm...................................... 1
To adjust the V-belts:
1. DISCONNECT LATHE FROM POWER!
2. Remove the end gear cover and the motor
access panel to expose the V-belts and
pulleys (see Figure 122).
Figure 122. End gear cover and motor access panel.
End Gear Cover
Motor Access
Panel