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Carriage Lock Screw; Power Feed (Half-Nut) Lever; X-Y Auto Feed Lever - OTMT SC4 User Manual And Installation Manual

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Carriage Lock Screw

For certain operations such as facing, in which
the tool is advanced across the face of the
work by the cross-feed handwheel, it is good
practice to lock the carriage to the ways to
prevent the carriage from moving during the
cut. If the carriage were to move during a
facing cut, the result would be a slightly
concave or convex cone-shape rather than a
perfectly flat surface on the end of the
Locking the carriage
The carriage is locked by turning the carriage
lock screw clockwise using a 5mm hex wrench.
When the locking screw is used for the first
time it may be in the locked position as
shipped from the factory to prevent the
carriage from shifting position during shipment.
Always check to make sure that the locking
screw is unlocked before attempting to move
the carriage with the carriage handwheel or
power feed.

Power Feed (Half-Nut) Lever

The Power Feed Lever, also known as the
Half-Nut Lever, is located on the right side of
the apron at the front of the lathe, next to the
carriage handwheel. It is used to drive the
carriage under power for turning and threading
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Power Feed (Half-Nut) Lever
When turned about 45 degrees to the right, it
clamps a pair of "half-nuts" around the thread
of the lead screw. If the lead screw is engaged
and rotating, the carriage will be moved along
the ways under power from the leadscrew.
Before engaging the Power Feed Lever,
ensure that the carriage is not locked to the
ways by the Carriage Lock Screw.
When the spindle is rotating in the Forward
direction, the carriage is moved towards the
headstock. With the spindle rotating in the
Reverse direction, the carriage moves away
from the headstock. Moving the lever back to
the vertical position disengages the half-nuts
from the leadscrew and stops the motion of the

X-Y Auto Feed Lever

Located on the right side of the apron, next to
the Power Feed Lever, the X-Y Auto Feed
Lever controls the motion of the carriage when
used with the optional milling head accessory,
but can also be used for lathe operations.
When using the X-Y Auto Feed Lever, the
Power Feed lever must be disengaged.