For anyone seriously interested in the technology of the period that thread on the Practical Machinist Antique Machines sub-forum is a good start. Asquith and Rivett 608 are both very knowledgeable while GW Wilson is the retired chief toolmaker at Colonial Williamsburg. There is another thread somewhere on that forum on the David Wilkinson screw cutting lathe...which we know was built and several sold to the US Ordnance Dept but the actual patent drawings were destroyed when the patent office burned during the War of 1812. The drawing now associated with the patent is a copy and there are questions as to how accurate it is.