Locking Spindle

[Daniel]

I apologize in advance if this has been covered but I can't find it.

I'm trying to take off my chuck and I'm using a steel rod set up in the jaws as a lever. I've engaged back gears but the lever has so much torque that it just spins freely. What's the best way to lock the spindle so I can take off the chuck?

I have an old Atlas 12" and I don't seem to have a locking ring.

Thanks-Dan

[Harold_V]

You have to be a little careful, for with some machines you can do damage to the back gear if you horse the chuck.
You might try placing an appropriate length of 2 x 4 between the jaw and bed. Back the chuck away, so the jaw doesn't make contact, the quickly turn the chuck until the jaw makes contact with the 2 x 4. The sudden stop may cause the fit to release. I'd suggest you do that with the lathe in back gear. so the works apply greater forces than would be available in direct drive. You'd place the piece of wood towards the rear, and turn the chuck backwards for this operation. Do this manually, not with the motor.

There has been reports of satisfaction in getting a chuck off by hanging a weight from the chuck (place a lever between the jaws, that projects towards the front of the lathe), applying penetrating oil to the thread, then walking away, allowing time to cause the fit to release. Never tried it, as I have a cam lock spindle, but if you're not in a hurry, you might consider giving that idea a go. I'd use as much weight as I could, with the spindle not being able to turn with the applied load.

One of the guys on the forum with such a spindle is most likely to step forward with some advice based on experience.

Harold

[neanderman]

On my Atlas 6", there is a pin that protrudes from the headstock gear nearest the chuck. When pushed in, the spindle is tied to the pulleys that surround it; pulled out, the spindle 'free wheels.'

If you engage the back gears with the pin pushed in, the spindle is effectively locked.

To remove my chuck, I lock the spindle as described above, put the chuck wrench in one of the sockets and give it a quick jerk.

Just don't forget to disengage the back gears before you turn the lathe on.

[ctwo]

You have to be a little careful, for with some machines you can do damage to the back gear if you horse the chuck.
You might try placing an appropriate length of 2 x 4 between the jaw and bed. Back the chuck away, so the jaw doesn't make contact, the quickly turn the chuck until the jaw makes contact with the 2 x 4. The sudden stop may cause the fit to release. I'd suggest you do that with the lathe in back gear. so the works apply greater forces than would be available in direct drive. You'd place the piece of wood towards the rear, and turn the chuck backwards for this operation. Do this manually, not with the motor.

There has been reports of satisfaction in getting a chuck off by hanging a weight from the chuck (place a lever between the jaws, that projects towards the front of the lathe), applying penetrating oil to the thread, then walking away, allowing time to cause the fit to release. Never tried it, as I have a cam lock spindle, but if you're not in a hurry, you might consider giving that idea a go. I'd use as much weight as I could, with the spindle not being able to turn with the applied load.

One of the guys on the forum with such a spindle is most likely to step forward with some advice based on experience.

Harold

I'm shocked! The way I first broke my chuck loose was to actually chuck up a piece of 2x4, a bit over a foot long, radially, manually rotate it until it hit the bed going forward, then turn on the lathe in reverse. I had it in a lower direct drive. The third whack and it came clean off...I thought I was doing it wrong...

[spro]

Yes the type Ed is referring to was used in the earlier 12 1/4" Atlas. That same bull gear is an indexing feature with 360 holes (of smaller dia. as the end of the pin). The full dia of the pin pushed into larger holes and i forget how many, just a few. This then doesn't rely on the teeth at all-which are fragile with shock. In fact that whole gear is fragile. There is a point where you find it is too tight and the gear is going to crack. There is a tool used by plumbers to grip the inside of pipe. They end with a square drive for a socket wrench or extension. They expand with external jaw teeth, aggresive, like a pipe wrench. So since the very inside of the spindle is only rough machined, one could put extreme torque against the chuck without involving the bull gear at all.

[Harold_V]

I'm shocked! The way I first broke my chuck loose was to actually chuck up a piece of 2x4, a bit over a foot long, radially, manually rotate it until it hit the bed going forward, then turn on the lathe in reverse. I had it in a lower direct drive. The third whack and it came clean off...I thought I was doing it wrong...

It's a little risky doing that under power. For one, the chuck can be dropped on the ways. By revolving the spindle by hand, you avoid that risk.

The 2 x 4 held radially is a good move, though. A lot easier to handle, and you can get more of a run at the bed. Infact, it can serve as the lever by which you propel the spindle. I wasn't thinking clearly.

Harold

[Daniel]

Thanks a lot! That really worked

[Fred Martin]

I have experience with a 4 jaw chuck and I've had these same problems when I was younger. The best advise I can offer is to take Harold's method and get it loose with the board and no power, then take a 1/8" bronze/brass brazing rod pretty close to ten inches long, put it in the lathe and put a 60 degree point on each end with a cutter or a file and bend each end 180 degrees apart, about 1/2" long. Then form a long "U" with it and adjusted just right you will have a tool to clean out the threads on any chuck for that lathe. Screw it through the chuck two or three times and then blow it out with an air hose real good. Put some oil on the spindle of the lathe and some inside of the chuck threads. It should go on easily then. I generally touch the back of the spindle easily, back it off a quarter turn and then take a cresent wrench on any jaw to snug it up against the end with the palm of your hand, no tighter. Then it will generally come off with the palm of your hand and crescent just as easily. You should do this every time you change chucks.
You should try putting a 4" piece of round steel in the chuck with the jaws either way and dial it in at the edge of the chuck and instead of "bumping", you can use a tapered piece of a wedge and find the high spot out on the end and then drive the wedge between the chuck and the steel (after trying this a time or two) you can bring it right down to where you want it. But, you have to go back and forth to get both places as close as you want them with an indicator without being so bouncy with the indicator . I have a new web address and will change shortly, (ohfred41@cinci.rr.com) if anyone needs my attention, or to curse at me...smile! ohfred