Southbend sb1015f specifications Half Nut Adjustment, To adjust the half nut

For Machines Mfg. Since 7/09 S E R V I C E EVS Toolroom Lathes

Gib

Screw

Figure 129. One of two rear saddle gib screws.

Left Gib

Screw

Figure 130. One of two front saddle gib screws.

Right Gib Screw

Figure 131. One of two tailstock gib screws.

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 1⁄8th of a turn.

Leadscrew

Half Nut

Adjustment Set

Screws

(Thread Dial

Removed)

Half Nut

Figure 132. Half nut gib adjustment.

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.

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