The ornamental design for a twin cavityballendscrew bit, as shown and described.
FIG. 1 is a perspective view of a twin cavity ball end screw bit showing our new design;
FIG. 2 is a left perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a front elevational view thereof, rotated 45 degrees from the position in FIG. 3;
FIG. 5 is a front elevational view thereof, rotated 45 degrees from the position in FIG. 4;
FIG. 6 is a front elevational view thereof, rotated 45 degrees from the position in FIG. 5;
FIG. 7 is a front elevational view thereof, rotated 45 degrees from the position in FIG. 6; and,
FIG. 8 is a front plan view thereof.
The broken line showing of the tool body in FIGS. 1-8 are included for the purpose of showing environmental structure and form no part of the claimed design.