Model of boring machine from design of Leonardo da Vinci

This model has been made in accordance with Leonardo da Vinci's design in the Codice Atlantico, folio 393 R.b, which was written between 1483 and 1518.

It was intended for boring out logs for water-pipes and pump-barrels and is particularly interesting for its use of two connected self-centring chucks in which the log may be rapidly fixed in position, correctly aligned and centred. The chuck pair is made up of two fitting coaxial cylinders, the inner of which carries the chuck jaws, and is mounted on a bench. The outer cylinder, to which the handles are attached, has toothed rims which engage with threaded cog-wheels. When these wheels are rotated, the screws, which pass through them and to which the jaws are attached, screw in or out. By moving one of the handles, therefore, the jaws are made simultaneously to open or close.

The boring bit is attached to the front of a pulley which was presumably intended to be driven by a belt. The tool is supported near the chuck by a fixed bearing and is fed into the log by means of a lead-screw in the bench, which is turned by a winch.