Southbend SB1038F - Manual (Page 71)

SERVICE
For Machines Mfg. Since 7/09 EVS Toolroom Lathes
-65-
S E R V I C E
Backlash Adjustment
Figure 126. Cross slide backlash adjustment screws.
Cap Screw
Set
Screw
Cross Slide Leadscrew
Tools Needed: Qty
Hex Wrench 3mm ................................................. 1
Hex Wrench 5mm ................................................ 1
Backlash is adjusted by loosening all four
cap screws shown in Figure 126, and then
tightening the center set screw, which pushes
down on a wedge and forces the nut apart, taking
up lash in the nut and leadscrew.
If you end up adjusting the nut too tight, loosen
the set screw, tap the cross slide a few times with
a rubber or wooden mallet, and turn the handle
slowly back-and-forth, until the handle turns
freely.
To re-adjust the backlash, rock the handle back
and forth and tighten the set screw slowly until
the backlash is at approximately 0.001" as
indicated on the handwheel dial.
Figure 125. Compound slide backlash adjustment set
screws.
Set Screws
Compound Leadscrew
Tools Needed: Qty
Hex Wrench 3mm ................................................. 1
Backlash is adjusted by tightening the set screws
shown in Figure 125. When these screws are
adjusted against the leadscrew nut, they offset
part of the nut to remove play between the nut
and leadscrew.
If you end up adjusting the nut too tight, loosen
the set screws, tap the compound a few times
with a rubber or wooden mallet, and turn the
handle slowly back and forth until it moves
freely.
To readjust the backlash, rock the handle back
and forth, and tighten the screws slowly until the
backlash is at approximately 0.001" as indicated
on the handwheel dial.
Backlash is the amount of free play felt
while switching rotation directions with
the handwheel. This can be adjusted on the
compound and cross slide leadscrews.
Reducing backlash to less than 0.001"
is impractical. Avoid the temptation to
overtighten the backlash set screw while
adjusting. Overtightening leads to accelerated
wear of the wedge, nut, and leadscrew.