Turning and Boring / A specialized treatise for machinists, students in the industrial and engineering schools, and apprentices, on turning and boring methods, including modern practice with engine lathes, turret lathes, vertical and horizontal boring machines

by Franklin Day Jones

Fig. 17. Turning a Gear Blank on a Vertical Turret Lathe

Examples of Vertical Turret Lathe Work.—In order to illustrate how a vertical turret lathe is used, one or two examples of work will be referred to in detail. These examples also indicate, in a general way, the class of work for which this type of machine is adapted. [Fig. 17] shows how a cast-iron gear blank is machined. The work is gripped on the inside of the rim by three chuck jaws, and all of the tools required for the various operations are mounted in the main and side turrets. The illustration shows the first operation which is that of rough turning the hub, the top side of the blank and its periphery. The tools A for facing the hub and upper surface are both held in one tool-block on the main turret, and tool A₁ for roughing the periphery is in the side turret. With this arrangement, the three surfaces can be turned simultaneously.

The main turret is next indexed one-sixth of a revolution which brings the broad finishing tools B into position, and the side turret is also turned to locate finishing tool B₁ at the front. (The indexing of the main turret on this particular machine is effected by loosening binder lever n and raising the turret lock-pin by means of lever p.) The hub, side and periphery of the blank are then finished. When tools B are clamped in the tool-blocks, they are, of course, set for turning the hub to the required height. The third operation is performed by the tools at C, one of which “breaks” or chamfers the corner of the cored hole in the hub, to provide a starting surface for drill D, and the other turns the outside of the hub, after the chamfering tool is removed. The four-lipped shell-drill D is next used to drill the cored hole and then this hole is bored close to the finished size and concentric with the circumference of the blank by boring tool E, which is followed by the finishing reamer F. When the drill, boring tool and reamer are being used, the turret is set over the center or axis of the table, by means of a positive center stop on the left-side of the turret saddle. If it is necessary to move the turret beyond the central position, this stop can be swung out of the way.

Fig. 18. Turning Gasoline Engine Flywheel on Vertical Turret Lathe—First Position

Fig. 19. Turning Gasoline Engine Flywheel—Second Position