I have had my dewalt DC925 hammer drill for a few years but is now out of warranty. It has had light usage over the last 3 years but there is now a lot of smoke coming from the commutator and you can see through the casing that the commutator is glowing hot especially in the joins of the copper segments. The brushes are fine, is there anything I can do to repair this as a new motor is quite expensive.

Bernie, August 2016

Yes - you can dismantle it and clean the commutator with fine emery cloth and make it shine - and use a wooden toothpick to clean out any crud between the segments.

Sometimes you can remove the brushes and feed in a strip of fine abrasive through one brush opening - around the comm and back out the way it came in - then rotate the chuck by hand.

Good Luck..., August 2016