Southbend SB1038 Leadscrew End Play Adjustment, Gib Adjustment, To remove leadscrew end play

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

Leadscrew End Play Adjustment

After a long period of time, you may find that the leadscrew develops a small amount of end play. This lathe is designed so that leadscrew end play can be easily removed with adjustment.

Tools Needed:	Qty
Open End Wrench 1"	............................................ 1
Hex Wrench 3mm	1
Hex Wrench 5mm	1

To remove leadscrew end play:

1.DISCONNECT LATHE FROM POWER!

2.Remove the three cap screws and end cover.

3.Loosen both retaining nut set screws shown in Figure 127.

Leadscrew

Retainer

Nut with Set

Screws

Figure 127. Leadscrew end play adjustment.

4.Engage the half nut lever.

5.Rotate the carriage feed handwheel back slightly and tighten the retaining nut at the same until the end play is removed.

6.Tighten both set screws and re-install the cover.

Gib Adjustment

The goal of adjusting the cross slide, tailstock, saddle, and compound gib screws is to remove sloppiness in the ways without over-adjusting them to the point where the slides become stiff and difficult to move.

In general, loose gibs cause poor finishes and tool chatter; however, over-tightened gibs cause premature wear on the slide, leadscrew, and nut, and are difficult to operate.

The gibs are tapered and held in position by a screw at each end. To adjust the gib, turn one screw a 1⁄4 turn clockwise and the other screw a 1⁄4 turn counterclockwise, so both screws move toward the same direction. Now test the feel of the sliding component by turning the handwheel, and adjust the gib screws as necessary to make it tighter or looser.

The gib adjustment process usually requires some trial-and-error. Repeat the adjustment process as necessary until you find the best balance between loose and stiff movement. Most machinists find that the ideal gib adjustment is one where a small amount of drag or resistance is present yet the handwheels are still easy to move.

Figures 128–131show the location of the screws for each gib on this machine.

Compound

Front Gib

Cross

Screw

Slide

Front

Gib

Screw

Figure 128. One of two cross slide and compound gib

screws.

-66-