This started out as an attempt to repair a keyless chuck but somewhere along the line it has turned into an autopsy.
Some time ago I fished a power drill out of a bin. It looked OK and when I plugged it in seemed to work perfectly - so I tried drilling a hole with it and discovered it had been dumped because the chuck didn't grip.
I cleaned the chuck as best I could with no improvement and then left it until today when I decided to take it to bits.
The outside all looked a bit fragile for gripping it in the vice so I screwed a 1/2 bolt into the back of the chuck and holding the rear section of the chuck whacked it on a hard surface a few times. It definitely moved so I held the rear section of the chuck in one hand and hit the bolt with a hammer and it came apart quite easily. I then opened the jaws and set it in the vice on the edges of the front section and using a drift inside the body knocked the body out the front section. The split nut and bearing came off easily and the front cap could be levered off with a screwdriver.
Here are all the bits.
Examination showed that the bearing race was far from smooth and clearly wouldn't allow you to tighten the chuck.
Here's a close up - which actually seems to make it look better than in real life.
The other side of the bearing (the back of the split nut) looks fine.
I thought about making a new one but I don't have any hardenable steel the right size and I think mild steel would quickly suffer the same fate as this one.
I think from this that if you have a hammer drill with a keyless chuck then the bit should be in contact with the back of the chuck to avoid the hammer action going through the bearings.
I've ordered a cheap keyed chuck off ebay.
Russell
