South bend SB1049F, Manual

Page: 63 / 136

For Machines Mfg. Since 5/11 13" Heavy 13
®
Gearhead Lathe
-57-
O P E R A T I O N
Apron Threading Controls
The half nut lever engages the carriage with
the leadscrew which moves the carriage and
cutting tool, along the length of the workpiece for
threading operations (see Figure 77).
Important: Make sure the feed selection lever
is in the disengaged (middle) position before
attempting to engage the half nut.
Figure 77. Apron threading controls.
Cross Slide
Disengaged
Feed Control
Lever
Carriage
Engaged
Halfnut
Lever
Disengaged
Feed Control
Lever
Half Nut
Lever
Thread Dial
The numbers on the thread dial are used with
the thread dial chart to show when to engage the
half nut during inch threading. The thread dial
gear must be engaged with the leadscrew for this
to work. Loosen the knurled knob on the thread
dial, pivot the dial gear toward the leadscrew
so that it properly meshes with the leadscrew
threads, then re-tighten the knob, as shown
Figure 78.
When threading, we recommend using the
slowest speed possible and avoiding deep
cuts, so you are able to disengage the half nut
when required and prevent an apron crash!
Figure 78. Thread dial engaged with the leadscrew.
Dial Gear
Leadscrew
Knurled
Knob