I have a B&D electric drill and the carbon brushes are sparking
excessively. (I'd expect a *little* sparking but this is a lot) Apart
from that the drill runs fine.

Inspecting the brushes there is about 1/4 the original length left and
the nds are rough, so they need replacement.

However, will replacing the brushes/cleaning the commutator cure the
sparking?

If not, what else could be causing the sparking?

S