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Proper way to remove a chuck from a threaded spindle

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  • Proper way to remove a chuck from a threaded spindle

    So I understand it's poor practice to use the back gears to lock the spindle when removing a chuck, but it's what I've been doing. Just wondering what's the correct way. I've got tons of machining books but I don't think I've ever seen the proper way.
    Darrell

  • #2
    Well I'll probably get flamed, but that's the way I was taught in the Navy's Machinery Repairman School and have used that method ever since. Not once have I broken a gear in the process.

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    • #3
      I do it all the time. Now, that being said I don't get out the 36" Rigid pipe wrench and jump on it with a pipe. A chuck should come loose with firm even pressure. I only recall once when it really didn't want to come off. For ones that are really stuck I made a large 36" long spindle wrench for the South Bend Heavy 10 as I had purchased a machine that hadn't had the chuck of for what may have been most of its life. That one was really on there.

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      • #4
        At least on old Atlas's and maybe other lathes, it's the pin that locks the front gear to the stack pulley that is taking the beating (such as it may be), yes you start seeing it in the back gears, but it's one of the reasons (not the only reason) that pin starts getting sloppy.

        Correct way to get the chuck off --whatever works and doesn't break anything --including the person removing the chuck (don't cross chuck a 2x4 and turn on the machine in reverse to loosen it for you --hey there are such people out there... for awhile anyway).

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        • #5
          Chuck a large bolt, then use a rattle gun on the ones that are stuck.

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          • #6
            If I had a screwed-nose/s aspindle with a serioulsly jammed on chuck I'd really consider unbolting/removing the chuck from the back-plate and removing thr back-plate by turning it down to the outside diameter of the spindle and if it didn't come off then, screw-cut the remnant until it was easy to remove or almost falls off.

            Knocking the back-gear train and the pin (and the holes on the gears for it)about will not improve things much at all.

            Even though you've used a "cheater bar" "lots of times before", if you snap a gear tooth or the pin and the chuck is still on the spindle you might wish you'd made a spare backing-plate and removed the jambed-on plate as above.

            "Bruised" back-gear teeth can be the cause of a "pattern" on an otherwise good job.

            Having other "bruised/weakened" teeth" or the "pin" let go or snap sure isn't going to improve you, your lathe or you job.

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            • #7
              The spindle on my lathe has a collar behind the threaded portion. On the face of it is the register surface, and around the outside of the collar there are three holes. These are meant for a wrench of sorts that lets you hold the spindle stationary while you remove the chuck. No forces get transferred to any gearing or pins.

              Your lathe must have something for a register surface, so it's quite possible you have these holes also- if not you could either drill some and make a wrench to suit, or maybe make a gripping device that would clamp around the collar tightly. As far as the chuck being so tight that it won't loosen, I'm with the camp that says don't beat on it. I don't like the idea of prying against the jaws either. I'd be more inclined to make a semi-circular tool that would notch into one of the pinions, then wrap about halfway around the chuck. Here you'd be putting pressure sideways on the pinion, which isn't going to hurt anything. You're not bending it, just hooking the tool into it. I don't know what that tool is called- bicycles use them for the bottom bracket. Something similar is called a pin wrench.
              I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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              • #8
                A word of caution here. I use the "lock the back gears" method and normally use a chuck key for leverage. I may hit the chuck key with the palm of my hand, but that is the limit of striking. If that fails, I will cross chuck an 18-36" wood scrap for leverage and apply pressure to it until it loosens. Here is the caution: do not strike the lever arm with a hammer or other heavy object. Want to know why not? Just look at used lathes on E-bay and count the ones described as having a broken tooth on the back gears. There are a lot. A sharp blow with a hammer will instantly apply a heavy shock to one or two gear teeth and this is very likely to break them. Wack: Snap! These gear teeth are intended for moderate, steady loads, not sudden shocks.
                Paul A.
                SE Texas

                Make it fit.
                You can't win and there is a penalty for trying!

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                • #9
                  Take the largest size pipe or tube or solid round bar that will fit inside the spindle. Taper the ID on one end, then make lengthwise slits. Weld a long handle on the other end.

                  Fashion a tapered plug with a threaded hole in the center. Install it with a bolt that can be tightened from the outer end of the pipe/tube/bar.

                  Slip the assembly into the spindle, tighten the bolt to expand the inner end, and you've got a nice handle to hold the spindle while you break the chuck loose.
                  Any products mentioned in my posts have been endorsed by their manufacturer.

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                  • #10
                    I used to just leave it in whatever gear it was in, insert a chuck key and give it a smack with a rubber or plastic mallet. Worked every time, and I figured since it was a relatively soft mallet...no harm done. Never hurt anything either.

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                    • #11
                      I put my atlas in back gear to remove the chuck. But like mentioned I only use the chuck key and my hand to loosen it. Haven't had a stuck chuck yet.
                      Andy

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                      • #12
                        My Atlas's 4-jaw was stuck tight, probably had not been off in a long time. I finally resorted to engaging back gears, clamping a 2x4 in the chuck, and whacking end far end of said 2x4 with a 3lb sledge. Finally, about the time I was were going to give up, it moved a little. It screwed right off then. The threads were clean as a whistle.

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                        • #13
                          Please don't use the back gears !
                          If you must, use a wedge of soft wood, like pine, between the gears
                          The bearings are stronger than a Cast Iron tooth and the force is spread over several teeth !
                          If you have to take the cover off the headstock, so be it , at least you preserve the integrity of the gears.

                          If the stuck chuck happens more frequently , better check the clearance between the spindle shoulder and the c'bore at the back of the chuck ( this area is sometimes reffered to as "The Registration" ..which it isn't IMHO) To tight a clearance will cause stuck chucks.

                          Rich

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                          • #14
                            Originally posted by Rich Carlstedt View Post
                            Please don't use the back gears !
                            If you must, use a wedge of soft wood, like pine, between the gears
                            The bearings are stronger than a Cast Iron tooth and the force is spread over several teeth !
                            If you have to take the cover off the headstock, so be it , at least you preserve the integrity of the gears.

                            If the stuck chuck happens more frequently , better check the clearance between the spindle shoulder and the c'bore at the back of the chuck ( this area is sometimes reffered to as "The Registration" ..which it isn't IMHO) To tight a clearance will cause stuck chucks.

                            Rich
                            +1 on the above. Hardwood wedge between headstock casting and the spindle gear. If you think this put undue stress on the headstock casting, it doesn't. This is what I was told by a former employee from the Sheldon Lathe Co.

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                            • #15
                              Originally posted by OKChipmaker View Post
                              Chuck a large bolt, then use a rattle gun on the ones that are stuck.
                              Seems to me that would be hard on the chuck.

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