Rose engine lathe by Hulot Fils 1768, mounted on table with treadle drive and complete with slide rest and chucks

This French 'Rose-Engine', made by Hulot Fils, is a typical example of its period. The headstock carries a mandrel which is free to move longitudinally in its bearings, whilst the whole headstock can move laterally on fulcrums.

On the mandrel is mounted a series of rosettes having both edge and side serrations which bear against rubbing pieces carried in two side frames. Under the influence ofthe rubbing pieces the serrations cause the mandrel to move rhythmically either laterally or longitudinally as desired, being held in contact with the rubbers by plate springs. Thus wavy lines, varying in pitch or depth, are produced by the cutting tool on the surface of the work. The mandrel is driven from a treadle shaft and the arrangement of belt pulleys on the mandrel and back shaft gives the effect of backgearing.

Various forms of chuck can be mounted on the mandrel nose. An early and somewhat unusual type of elliptical chuck is shewn dismantled.

The tool rest consists of a main slide which can be set for either sliding or surfacing, with a subsidiary tool slide and tool holder set at right angles, both movements being made by hand-operated screws. The tool rest has a screw-adjusted stop for setting the tool.

In the same case is shewn a separate headstock by the same maker fitted with guide screws for cutting threads. To this headstock is screwed a double eccentric chuck.

A spherical or dome chuck of about 1815 by Holtzapffel is also included in the equipment of this lathe.