Pitch

Depth

Helix angle

Lead

Connecting spindle gear to fixed stud gear

Connecting fixed stud gear to quick change gear box

Connecting quick change gear box to lead screw

Connecting lead screw to changing dial

Reduce gear ratio

Transmit power between driver and driven gears

Reduce spindle speed

Increase spindle speed

Major dia of work

Pitch

Root dia of work

Angle of thread

Driver 60 driven 50

Driver 40 driven 20

Driver 85 teeth driven 60 teeth

Driver 100 teeth driven 25 teeth