Unique and versatile thread-cutting attachment for lathe Contains 15 metal gears, mounting brackets, engagement mechanism and a 4" handwheel Gear ratio chart and detailed instructions are included Weight: 3 lb.a This low cost Sherline Thread-Cutting Attachment enables you to machine 36 different unified thread pitches (5 to 80 threads per inch) and 28 different metric thread pitches (from .25 to 2.0mm). It allows you to cut them as either left-hand or right-hand threads. The lathe tool can be ground to cut any of the various thread forms, and any of these various pitches or thread forms can be cut on any pitch diameter you desire. Threads are generated on the Sherline lathe by gearing the spindle to the leadscrew. As the spindle is rotated with the handwheel, the tool will advance an amount determined by the ratio of the gears. When the tool has completed its movement, you simply stop cranking, back up the tool and turn the spindle in the opposite direction until the tool is past its starting point. Then reset the tool and you're ready for the next pass. It is simple, by using a 127-tooth gear (supplied), true metric threads can be cut on an inch (model 4000, 4500, or 4400) or true inch threads on a metric (model 4100, 4530, or 4410) lathe. Note: Manufacturer has done a special short run of gears with tooth counts in between the ones included in the set. If you need special gears to do a thread count different from the ones mentioned in the table, these gears might help you achieve it. The gears have tooth counts of 21, 23, 25, 27, 29, 31, 33, 35, 37 and 39 teeth.
