Origin of the screw thread. Ancient boring tools. Suggestions of the screw form. The "Worm Gimlet." Making the first nuts. An old device for cutting threads in wood. Archimedes and his helical device for raising water. Jacques Berson's French lathe. Joseph Moxan's English lathes. The French lathe of 1772. John Maudsley's English lathes. Maudsley's slide-rest. Another French lathe. The use of a "master screw." A form of slide-rest. An old-time worm and worm-gear. Simple method of developing the screw thread. Anthon Robinson's triple-threaded screw. The many uses of the early lathes. An old "chain lathe." Its detailed construction. Cutting left-hand threads. Crown gear and "lantern pinion" for operating the lead screw. Transition from wooden to iron lathe beds. The Putman lathe of 1836. The Freeland lathe of 1853. Various classes of lathes to be illustrated and described.

The origin of the screw thread, or the threaded screw, reaches so far back into ancient times that it is impossible to determine when, where, or by whom it was first conceived or used. That it was known in one form or another as far back as the use of iron for tools is altogether probable. Holes must have been made in wood by some kind of an iron instrument which was the predecessor of the gimlet. This instrument was most likely square or of some form nearly approaching that. In order to be at all effective it must have had sharp corners.

As the straight-edged sharp knife was first accidentally and then purposely hacked into notches and became the first saw, so may the corners of the early boring instruments have had notches formed in them to facilitate their action upon the material to be bored. These notches may have been gradually deepened for the same purpose, with the idea that the deeper they were the more useful they would become. We can very readily conceive that in making these notches the tool was laid on its side and gradually revolved as the notches were made, beginning at the point and working upwards as the tool was revolved. This of itself would have a natural tendency to produce a semblance of a screw thread, which would increase the efficiency of the tool by drawing it into the wood to be bored. When this tendency was noticed it was also natural to see why it acted in this manner and to increase this action by more carefully making these notches. In time the "worm gimlet" was undoubtedly evolved.

The form of a screw thread having once been arrived at, the realization of its usefulness for various purposes was only a question of time. It is altogether probable, however, that for the purpose of holding parts of a machine together, or for similar mechanical purpose, screws were first made of wood. It is also pretty certain that they were first made in a very crude form without much regard to the exactness of the pitch or form of the thread, although the V-thread would be the most natural because the most simple form. It is also generally conceded, of course, that they were made by hand and probably with the rude knives then used, as hand tools were the only ones in use.

As to the methods used in making the first nuts for use with the screws, it is probable that they were quite thin as compared with the pitch of the thread, possibly containing but two or three complete revolutions of the thread, which was worked out by sharp-pointed instruments, as the point of the knife or by similar means. This method may have led to the insertion of a metal tooth in a wooden screw and the cutting of the thread in the nut in this manner. We do know for a certainty that a somewhat similar means was used many years later, as the author saw a device such as is represented in Fig. 8, which was preserved as a curiosity, representing the early mechanical method of doing this work.

This device consisted of a turned and threaded screw D, of very hard wood, having one end turned down to a diameter equal to that at the bottom of the thread, while the opposite end was made much larger and contained a hole for passing a bar or lever by means of which it was rotated. At the termination of the thread and beginning of the smaller straight portion the thread was cut away, leaving an abrupt termination, and at this point was inserted a tooth of steel formed in a rough manner to the shape of the thread.

Fig. 8.   Screw Threading or Tapping Device for Wood.

Fig. 8. - Screw Threading or Tapping Device for Wood.

In a wooden nut A a thread had already been cut, by some manner unknown, and through this the screw D was fitted. The piece B, to be tapped or threaded, was clamped to this by means of the steel clamps E, E, binding the two firmly together. To all appearances the tooth or cutter d could be set in or out so as to cut merely a trace of the thread the first time through, then another deeper cut, and finally finished to the full depth. The author had no means of ascertaining the origin of the device, but the wood of which it was composed was black with age and the man who possessed it could not tell how many years his father had owned it or where he got it. It was certain, however, that both of them had been mechanics who had made and repaired the old-time wooden spinning-wheels in which a wooden screw about one inch in diameter had been used for tightening the round band by which the twisting mechanism was operated.

Archimedes, the most celebrated of the ancient mathematicians, certainly had a good idea of the screw thread, as is shown in his famous screw made of a pipe wound helically around a rotating cylinder with which he raised water fully two hundred years before the Christian era. Still it was doubtless a long time after this period before the screw was constructed so as to be applicable to the uses of the present day. Of the progress and development of this and other similar mechanical matters in these early times we have little authentic information. The development of such simple machines as the lathe preceded much that was mechanically important, and to its influence we owe a great deal of the early advancement in the mechanic arts.