Although I have never had the unfortunate experience of trying to remove an overtightened faceplate or chuck from a spindle, I recently had a spindle/chuck problem that I want to share so others may avoid it. I apologize in advance for the length of the message.
The problem:
Last week, I was rough turning some pieces mounted in my Vicmarc VM120 chuck which I had spun on/off a few times during the evening with no issues. I then go to thread it back onto the spindle and it starts to bind up as the chuck adapter starts over the unthreaded shoulder of the spindle. I unscrew it, using more effort than normal and have a look to see whats going on. The shoulder on the spindle looks a bit scarred so I take a file and gently remove the minute burr that appears to have formed. I then proceed to re-install the chuck and it goes on pretty smooth right up to about 1/16" from seating. It binds up again except this time, as I try to unscrew it, it seizes up solid.
The solution:
After trying a few methods to get it off, each of which resulted in profanity echoing through the shop, I finally accepted that I needed outside help on this problem. I removed the chuck body from the seized adapter and disassembled and removed the spindle completely from the headstock. I then sucked up to the millwright that lives next door for assistance and agreed that destoying the adapter was the only option (far cheaper to replace than the spindle) so he took it to work and machined the adapter off, keeping clear of the spindle thread and shoulder.
The cause:
I needed to determine why this happened at all and this is my conclusion:
I had drilled a 1/2" hole all the way through the last piece of wood I had mounted in the chuck. When the bit broke through on the chuck side it dropped chips into the adapter body. When I removed the chuck, one or more of the tiny chips fell into the adapter threads and when I spun it back on the spindle, the male threads pressed the chips into the internal threads of the adapter, creating a minute off-center misalignment. The inside diameter of the adapter has a very close tolerance to the diameter of the shoulder on the spindle and the misalignment caused it scrape the surface of the shoulder as it went on. For reasons I can't explain, the scraping turned into galling on the spindle, raising a 'splinter' of metal as it went along. When I tried to remove the chuck, the splinter folded over the other direction jamming the adapter to the shoulder (like a undesirable pin chuck). The more I forced it, the tighter it got. Check the attached pictures for the damage (which I have repaired enough to be functional again, but its not pretty).
Prevention:
It is my belief that had I been more diligent in keeping the internal thread of the chuck adapter clean, this problem would have never occurred. Draw your own conclusions, but I will ensure that my chuck and faceplate threads are clean from now on.
Steve
Vicmarc VL175SH and possibly a Delta 46-460 Midi in the near future.
The problem:
Last week, I was rough turning some pieces mounted in my Vicmarc VM120 chuck which I had spun on/off a few times during the evening with no issues. I then go to thread it back onto the spindle and it starts to bind up as the chuck adapter starts over the unthreaded shoulder of the spindle. I unscrew it, using more effort than normal and have a look to see whats going on. The shoulder on the spindle looks a bit scarred so I take a file and gently remove the minute burr that appears to have formed. I then proceed to re-install the chuck and it goes on pretty smooth right up to about 1/16" from seating. It binds up again except this time, as I try to unscrew it, it seizes up solid.
The solution:
After trying a few methods to get it off, each of which resulted in profanity echoing through the shop, I finally accepted that I needed outside help on this problem. I removed the chuck body from the seized adapter and disassembled and removed the spindle completely from the headstock. I then sucked up to the millwright that lives next door for assistance and agreed that destoying the adapter was the only option (far cheaper to replace than the spindle) so he took it to work and machined the adapter off, keeping clear of the spindle thread and shoulder.
The cause:
I needed to determine why this happened at all and this is my conclusion:
I had drilled a 1/2" hole all the way through the last piece of wood I had mounted in the chuck. When the bit broke through on the chuck side it dropped chips into the adapter body. When I removed the chuck, one or more of the tiny chips fell into the adapter threads and when I spun it back on the spindle, the male threads pressed the chips into the internal threads of the adapter, creating a minute off-center misalignment. The inside diameter of the adapter has a very close tolerance to the diameter of the shoulder on the spindle and the misalignment caused it scrape the surface of the shoulder as it went on. For reasons I can't explain, the scraping turned into galling on the spindle, raising a 'splinter' of metal as it went along. When I tried to remove the chuck, the splinter folded over the other direction jamming the adapter to the shoulder (like a undesirable pin chuck). The more I forced it, the tighter it got. Check the attached pictures for the damage (which I have repaired enough to be functional again, but its not pretty).
Prevention:
It is my belief that had I been more diligent in keeping the internal thread of the chuck adapter clean, this problem would have never occurred. Draw your own conclusions, but I will ensure that my chuck and faceplate threads are clean from now on.
Steve
Vicmarc VL175SH and possibly a Delta 46-460 Midi in the near future.
