The Cataract lathe could, like most quality lathes of its type, be provided with either changewheel-driven "top-slide" or traditional "chase" screwcutting - the latter system devised by Joseph Nason of New York who obtained US Patent No. 10,383 on January 3rd, 1854 for an "arrangement for cutting screws in lathes." In the Cataract interpretation of the system a T slot, which ran down the back face of the specially-cast bed, held supports carrying a sliding transmission bar and, above it, a "master thread". At the headstock end of the assembly additional gearing was provided to extend the threading range (by a multiple of six) for each thread master used. A follower (with an interchangeable tip carrying a few threads of the same pitch) pressed into the master thread and transmitted its motion, via a sliding bar, to a threading tool held against the workpiece in an adjustable toolholder.
Whilst this system produced absolutely-accurate threads, and was especially suited to delicate operations on the thin-wall tubes used to construct such items as microscopes and the bodies of camera lenses, the length of thread that could be cut, and the number of threads per inch or mm, depended upon the availability of the appropriate thread master. A useful touch was that Cataract master threads (like Pratt & Whitney's) could be supplied complete with a hob at one end for chasing nuts to suit the thread being generated in the lathe. An alternative form of screwcutting, and the only type available on lathes with a "plain" bed, was provided with a set of changewheels and a splined, universally-joined shaft which drove the top slide; the arrangement is illustrated below..