The ornamental design for a handle bar for a conduit dredge, as shown and described.
FIG. 1 is a perspective view of a handle bar for a conduit dredge, showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof; and,
FIG. 6 is a top view thereof.
The dash dot dash lines represent boundary lines of the claimed design and form no part thereof. The evenly spaced broken lines illustrate environment and form no part of the claimed design.