THE LATHE IS ONE OF THE OLDEST complex tools known to man, but determining an exact date of its invention is impossible. The first lathes were undoubtedly springpole or bow lathes that were powered by the operator. On a typical springpole lathe, the work was held between a set of “dead” centers, which were merely metal points (see the drawing on the facing page) . Except for these two metal points, the rest of the lathe was wood.
The bed of the lathe consisted of two stout timbers. On this was mounted a set of “poppits, ” which carried the dead center points. A rope was attached to a tree branch above the lathe, wrapped several times around the work, and attached to a lever arm that the turner moved up and down with his foot. Cutting was only accomplished on the down stroke, the tree branch providing a mild spring to return the rope for another power stroke.
Later, during medieval times, the pole lathe was brought inside, and the tree branch was replaced with a long bow mounted above the lathe. The rather powerful bow had two strings that passed through offcenter holes in a large wood spool onto which the rope was wound. Stepping down on the lever arm turned the work, wound the spool, and compressed the bow. The bow then turned the spool in the opposite direction, revolving the work backward and returning the lever arm to the up position.
A later bow lathe replaced the tree branch and rope with a small bow. The bow was grasped by the operator and seesawed back and forth. Unless a helper could be found, the operator had to hold the tool with one hand. In India, Afghanistan, and Southeast Asia, it is still common to see workers using bow lathes on the ground and guiding the tools with their toes and left hands while they work the bows with their right.
These early lathes could only turn between centers because poppits carried immovable, or dead, centers. Modern lathes came about when the left-hand poppit was given a rotating, or live, spindle and the right poppit was given a retracting spindle. Thus, the headstock and tailstock were born. Needless to say, the headstock also made modern faceplate turning possible.
The first live spindle was nothing more than a steel spindle that frt precisely bored holes in each end of a cast-iron frame. These were called plane bearings. In the 19th century, plane bearings gave way to babbitt, ball, and roller bearings.
These innovations made possible the construction of the great-wheel lathe. In this type of lathe, a pulley on the headstock spindle was belted to a large, or great, wheel 4 ft. to 10 ft. dia. The great-wheel lathe was a direct product of the guild system, under which apprentices or slaves would turn the wheels. Later, water, steam, and gasoline provided the muscle, allowing the great wheel to be replaced by an overhead shaft.