The work A shown in Fig. 2 is a steel forging of an automobile hub which is held in a three-jawed chuck by the flange B, the tapered portion entering the hole G in the chuck body. The inside of the hub is to be threaded at K with a collapsing tap. A recess is therefore needed at L in order to obtain a clean thread. The machine selected for the work is a Pratt & Whitney turret lathe having a cross-sliding turret of the flat type. The recessing tool is of high-speed steel, with the shank turned and ground cylindrical at E. The front end is also turned to form the flange D, and is afterward cut away and finished to the shape required, as clearly shown in the lower part of the illustration. The tool-holder F is of cast iron and contains a steel split bushing J which is compressed by two screws H in the top of the holder. The action of this tool was satisfactory, but the upkeep is obviously rather expensive.

Fig. 2. Recessing Tool used in a Turret Lathe.