Smoking Drill - End of Useful Life?

thor

I've got a Bosch Hammer Drill which I've been using very infrequently over the last 10 years without any issues but just recently it started smoking and slowing down considerably to the point that it is now ineffective. After googling I've discovered that the problem is likely that friction in the gears is likely the cause and that the damage is irreversible. Is this true? If I opened it up and lubricated(I've got some white lithium grease) the mechanism is there a chance that the drill can return to normal or will I just have to give up on it and learn a lesson that I should have greased it at regular intervals?

Lorian

It could be the motor brushes gone you will need to open it and look. 

FreeBear

Open up, give the gearbox a good clean and pack with fresh grease. While it is apart, replace the carbon brushes and give the commutator a light clean.

New brushes will be less than £10 (perhaps as cheap as £5), and the grease costs next to nothing. So you don't really have much to lose.

I have a Bosch that was purchased over 30 years ago. Aside from a new set of brushes, I've never bothered with greasing the gearbox. Still going strong, and I've given it some serious abuse over the years.

Section62

thor said:

I've got a Bosch Hammer Drill which I've been using very infrequently over the last 10 years without any issues but just recently it started smoking and slowing down considerably to the point that it is now ineffective. After googling I've discovered that the problem is likely that friction in the gears is likely the cause and that the damage is irreversible. Is this true? If I opened it up and lubricated(I've got some white lithium grease) the mechanism is there a chance that the drill can return to normal or will I just have to give up on it and learn a lesson that I should have greased it at regular intervals?

I'd be amazed if it was the gears - the torque an electric drill can deliver when drilling should easily overcome any drag on the gears due to old grease.

Where is the smoke coming from, and does it have an 'electrical' smell?  It could be the brushes, but if it has an electronic variable speed then it might be that going iffy.  My old Bosch (40+ years old) started to go wrong - it was one of the suppression capacitors which had failed and obviously had been very hot at some point.

thor

The smoke appears to be coming from between the keyless chuck and torque adjustment collar(I had to google the name of those parts). I've not had the time to open it up but when I do will I be able to see the carbon brushes to see if they are damaged? Also why do drills slow down if the brushes begin to melt? Is there some kind of thermal regulation that throttles the drill?

kipperman

The other strong possibility is that the insulation between the windings has broken down - usually accompanied by significant sparking from the brushes. Terminal if that is the case

FreeBear

thor said:

The smoke appears to be coming from between the keyless chuck and torque adjustment collar(I had to google the name of those parts). I've not had the time to open it up but when I do will I be able to see the carbon brushes to see if they are damaged? Also why do drills slow down if the brushes begin to melt? Is there some kind of thermal regulation that throttles the drill?

The brushes will be at the other end of the drill. If they are getting worn out, the drill usually stops working or runs intermittently.

Smoke coming out of the ventilation slots usually indicates one or more windings are getting way too hot. Often leading to the insulation breaking down and becoming terminal - In the early years with my drill, I abused it by drilling ~36mm dia holes in some thick slabs of aluminium. Had a bit of smoke wafting out. Left it to cool down, and took it a bit slower with the big holes.