Question 159General Subjects - QMED

The correct answer is D) split or half-nut. To commence cutting threads with a metal lathe, you need to engage the split or half-nut mechanism. This mechanism engages the lead screw of the lathe, which allows the carriage to move at the proper rate to cut the desired thread pattern. The other options are not involved in the threading process - the feed-change lever controls the feed rate for regular turning, the back gear lever changes the gear ratio for higher torque at lower speeds, and the thread-chasing dial is used to manually control the threading process.