The work A shown in Fig. 5 is a bronze rear axle housing for an automobile, and the recessing bar is only one of a group of tools used at the same setting of the work. Previous to this setting the finished annular rings at the two ends D and E of the casting were machined so that they might be used as locating points in this setting. The ring D slips into the split bushing in the holding device B. The other end E revolves in a roller back-rest F which is placed on the ways of the turret lathe. This back-rest is not shown in detail, as its construction is not essential in connection with the recessing tool. The two grooves in the work at 8 were to be spaced an exact distance part and it was partly to insure accurate spacing that this bar was designed, although rapidity of operation was also a factor. A cast-iron bracket K is fastened to the dovetailed face of the turret by means of gib Y shown in the lower view. The handwheel W is connected to a shaft which drives the pinion M. A steel pointer X is fastened to the bracket and acts as an indicator on the graduated rim of the wheel. It will be seen that this arrangement makes it very easy to determine the depth of the cut.

The pinion M meshes with a rack cut upon the enlarged end N of the operating rod L. This rod is considerably below the center of the bar and is flatted at 0 and P. The tongues Q and R are angularly-cut on these surfaces, and they engage with grooves on the under side of the tool-carrying blocks T, so that any longitudinal movement of the rod L is transformed into a radial movement of the blocks. The grooving tools 8 are of round section and are held in position by the headless screws Z. The backing-up screws U permit accurate adjustments to be made with ease. The pilot H enters the steel bushing C in the body of the holding device and assists in preventing chatter. An added refinement to this tool was an oil-groove from which oil was lead directly to the cutting tools. This was supplied with oil through a special piping system and a distributing collar on the turret. In order to avoid confusion in the drawing, this has not been shown. This device gave very satisfactory results.

Fig. 5. A Double Recessing Tool Arrangement for a Rear Axle Housing.