Milwaukee 28 volt hammer drill

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Anyone ever tore one down? I think I need brushes, but looking online it appears they changed several times over the years, some the brushes only come with the motor, some come with the switch assembley, and some you can just get the brushes. Can't read my model # any more so I'll just have to tear it down. Started spitting sparks out the vent slots today, about 10 minutes into use with a new battery.Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:I tore it apart expecting the brushes to be worn down to the wires, but there was still about 1/2" left on them. Does anyone know if DC motor brushes are the same composition for their entire length, or is there two types of metal making them up.It spits sparks and occasionally tiny particles, not while working, but when braking.I had been limping it along on old batteries, now I have a new one in it, lots more power and rpm, maybe I just need to keep working it.Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:Brushes aren't metal there carbon. I think your barking up the wrong tree, if the motor is turning, and your not down to metal on the brushes I don't think thats your problem.By your description of your fault look at your brake parts, sounds like something is buggered up there.
Reply:Well that makes perfect sense, only problem is I don't have a clue how the brake actually works, and what parts are involved. Somehow I thought the brushes were involved with braking.Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:Brushes are carbon formed around copper wire, usually with a tab on the end of the wire for better retention.  Some manufacturers use a limiting setup to keep the brushes from moving close enough to the commutator to do any damage, those without can wear down and expose the copper, then you will have metal  to metal contact."The man of great wealth owes a peculiar obligation to the State, because he derives special advantages from the mere existence of government."  Teddy RooseveltAmerican by birth, Union by choice!  Boilermakers # 60America is a Union.
Reply:Don't think so, maybe a holder around the brush holder assembly but I don't think so. Also I didn't answer your question but there is no big difference between a AC brush and a DC brush, Makita and a few other brands make AC and DC grinders, same motors same brushes.