For Machines Mfg. Since 7/09
EVS Toolroom Lathes
-67-
S E R V I C E
Half Nut Adjustment
The half nut mechanism can be tightened if it
becomes loose from wear. The pressure exerted
by the half nut is controlled by a gib similar to
the one in the saddle, which is on
Page 66
. The
half nut gib is adjusted with two set screws.
Tool Needed:
Qty
Hex Wrench 3mm ................................................. 1
To adjust the half nut:
1.
Disengage the half nut.
2.
Remove the thread dial.
3.
Turn the two half-nut adjustment set screws,
shown in
Figure 132
, clockwise about an
1
⁄
8
th
of a turn.
Figure 132. Half nut gib adjustment.
Leadscrew
Half Nut
Adjustment Set
Screws
(Thread Dial
Removed)
Half Nut
Right Gib Screw
Figure 131. One of two tailstock gib screws.
4.
Engage/disengage the half nut several times
and notice how it feels (you may need to
move the carriage handwheel slightly to get
the half nut to close).
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.
5.
Repeat
Steps 3–4
, if necessary, until you are
satisfied with the half nut adjustment. (If
the half nut becomes too stiff, turn the set
screws counterclockwise to loosen it.
6.
Re-install the thread dial.
Figure 130. One of two front saddle gib screws.
Left Gib
Screw
Figure 129. One of two rear saddle gib screws.
Gib
Screw
