Fig. 9. Turning the Rim of a Flywheel
Turning a Flywheel on a Vertical Mill.—The turning of a flywheel is a good example of the kind of work for which a vertical boring mill is adapted. A flywheel should preferably be machined on a double-head mill so that one side and the periphery of the rim can be turned at the same time. A common method of holding a flywheel is shown in [Fig. 9]. The rim is gripped by four chuck jaws D which, if practicable, should be on the inside where they will not interfere with the movement of the tool. Two of the jaws, in this case, are set against the spokes on opposite sides of the wheel, to act as drivers and prevent any backward shifting of work when a heavy cut is being taken. The illustration shows the tool to the right rough turning the side of the rim, while the left-hand tool turns the periphery. Finishing cuts are also taken over the rim, at this setting, and the hub is turned on the outside, faced on top, and the hole bored.
Fig. 10. Tool B set for Boring the Hub
The three tools A, B and C, for finishing the hole, are mounted in the turret. Bar A, which carries a cutter at its end, first rough bores the hole. The sizing cutter B is then used to straighten it before inserting the finishing reamer C. [Fig. 10] shows the turret moved over to a central position and the sizing cutter B set for boring. The head is centrally located (on this particular machine) by a positive center-stop. The turret is indexed for bringing the different tools into the working position, by loosening the clamping lever L and pulling down lever I which disengages the turret lock-pin. When all the flywheels in a lot have been machined as described, the opposite side is finished.