- Joined
- Dec 8, 2015
- Messages
- 111
Does anyone know what the finish of the bores should look like in a Jacobs chuck body ?
I acquired a Jacobs 6A chuck and decided to disassemble, clean and lube – since it had a gritty feel when turning. This was the first time I had disassembled a drill chuck. I noticed that the bores in the chuck body, where the jaws slide into, had pronounced annular lines as though they were just drilled and not reamed. One of them had a pretty rough finish with a few very heavy score marks going around the bore. (Sorry I did not take any pictures of this chuck). The hardened jaws on the other hand looked ground with no wear marks. They fit tightly in the bores. I did not know if these lines are from, use, misuse or acceptable factory finish.
Also, the ends of the nut, where it was split in half were rough as if they broke the nut in half, instead of cutting. Perhaps small metal shards are what caused the gritty feel or the marks in the bore. But I cannot imagine them scoring around the bores instead of linearly.
The rest of the chuck looks to be in good shape, not abused or worn. The flats on the jaws were even the entire length. Currently the chuck arbor does not fit any of my machines to test accuracy
I acquired a Jacobs 6A chuck and decided to disassemble, clean and lube – since it had a gritty feel when turning. This was the first time I had disassembled a drill chuck. I noticed that the bores in the chuck body, where the jaws slide into, had pronounced annular lines as though they were just drilled and not reamed. One of them had a pretty rough finish with a few very heavy score marks going around the bore. (Sorry I did not take any pictures of this chuck). The hardened jaws on the other hand looked ground with no wear marks. They fit tightly in the bores. I did not know if these lines are from, use, misuse or acceptable factory finish.
Also, the ends of the nut, where it was split in half were rough as if they broke the nut in half, instead of cutting. Perhaps small metal shards are what caused the gritty feel or the marks in the bore. But I cannot imagine them scoring around the bores instead of linearly.
The rest of the chuck looks to be in good shape, not abused or worn. The flats on the jaws were even the entire length. Currently the chuck arbor does not fit any of my machines to test accuracy