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4-jaw removal cornfusalment

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  • 4-jaw removal cornfusalment

    Ok, this 4-jaw hasn't been off the lathe in 2 years at least - that's when the previous owner passed. And there were no additional chucks or faceplates. I can only conclude that this 4-jaw may have been on the lathe for a very long time.

    How do I get it off? I've thought about it so much I'm completely confused. It's a Craftsman 12".

    The chuck needs to be spun clockwise to be removed, yes?

  • #2
    Not sure but the cincinatti at school has a taper-key spindle and the chuck un-threads counter clockwise. Also i think the southbends with threaded spindle noses were right hand thread so you spin the chuck counter clockwise to get it off but i've never worked with one...


    • #3
      I don't know the Craftsman 12", but I'm pretty sure they were all threaded spindles. So, there should be some means to lock the spindle against rotation. Then chuck should have some feature for attaching a spanner or some sort of bar to turn it counter-clockwise (standard right hand thread) and unscrew the chuck. Don't drop it on the ways!

      If it's been on there a long time, it may be necessary to get more "serious" with it. I've head of folks putting a board under the chuck to protect the ways when/if it drops, then clamping a board in the chuck jaws, extending from one side over the ways. They then run it backward in back gear to break them loose.
      Master Floor Sweeper


      • #4
        Errr,no.the chuck needs to be turned anti-clockwise for removal.If it was the other way,your chuck would spin of at the first sign of a load on it.
        That is to say,if your standing in front of the lathe,with the headstock on your left,spin the chuck towards you.If possible,lock the geartrain,or at least in the lowest gear possible.Chuck a piece of scrap steel in the jaws,so it sticks out beyond the chuck.Hit this bit with a good size hammer,and it should free up.
        If it doesn't come off,spray wd-40 or similar on spindle thread,and leave overnight.Should come off nicely in the morning.
        If it doesn't,I'm out of ideas.


        • #5
          btw.Baddog's point about a board on the ways is a very good one.I use a cheap polypropylene cutting board for this very purpose.


          • #6
            If you put it in back gear and put too much pressure on the gears you may break a tooth on the backgear. If I was removing a stuck 4 jaw chuck I would put an inch bar in the chuck and use an eight point socket with an air wrench after soaking it for a week or so with liquid wrench or a similar penetrating oil. I would use a strap wrench on the drive pully instead of back gear. If all else fails you may have to remove the chuck from the backplate and turn it off.
            my two cents worth, I would interested to know how you finally get the chuck off.
            Herm Williams


            • #7
              The chuck is threaded on with a right hand thread and is removed by turning counterclock wise as matador said.

              Put it in back gear and run one of the jaws out to the OD of the chuck. Take an 8" +/- long piece of 3/4" key stock or something similar and lay one end of it flat on the face of the chuck perpendicular to the jaw at the outer edge of the face. Hit it smartly with 1 or 2 pound hammer. A few hits should do it. Be sure the end of the bar on the jaw is square and flat on the jaw. It is important to hit the jaw at the face of the chuck, not away from the face.

              This is the way it is done in almost all machine shops. But if you are a purist and fanatic then there are ways to spend hours and/or days to remove it.

              EDIT: You can use the lowest gear without the back gears and sometimes it will break loose. As mentioned in following posts, the back gears are sometimes easy to break.
              Last edited by Carld; 11-08-2007, 09:52 PM.
              It's only ink and paper


              • #8
                When I removed my 3 jaw from my L1 nose, presumably for the first time in a zillion years, I had a lot of trouble. I put 2x6s over the bed, put a big high quality prybar between the chuck jaws and bound agains the 2x6s. Put my spanner wrench on the chuck lock collar and couldn't buge it. I ended up with a 8' extension on my spanner and actually rocking the 15x48 lathe onto its feet before the collar finally broke free. The manual said specifically not to put a extension on the spanner, but I didn't have any other choice. I had soaked it in penetrating lube for days. It was to close to seals and the Gamit bearings to risk heat, so it had to be leverage. I nearly had to change my shorts when the collar let loose, it made a huge bang! All is well now though, and the threads are antiseezed...



                • #9
                  Be careful on your bashing, that you don't break the back gears or the locking pin.

                  First thing I'd try is putting it in backgear and don't pull the locking pin; this ought to lock the spindle against rotation. Arrange to have one of the chuck's key holes on top of the chuck. Insert chuck key, and give it a vigorous yank towards you. If you're lucky, that will be sufficient to start the chuck unscrewing.

                  If you're not lucky, more persuasive measures will be needed, and at this point my initial cautionary sentence about being careful not to break something kicks in. I would be careful of doing anything much more forceful and relying on the back gears to lock the spindle. I don't think Atlas gears are known for their strength. Figure out some other way to keep the spindle from turning. One thing you could do, though it would take a bit of preparation, is clamp a couple of pieces of wood together with two bolts, then bore a hole between them on the dividing line just big enough to go around the spindle. Use the boards and bolts to clamp the spindle in place -- you might have to shave a little off the boards' mating surfaces to get clamping to happen. Then stick a bar between the chuck jaws and belt it with a hammer, as somebody else suggested.
                  Try to make a living, not a killing. -- Utah Phillips
                  Don't believe everything you know. -- Bumper sticker
                  Everybody is ignorant, only on different subjects. -- Will Rogers
                  There are lots of people who mistake their imagination for their memory. - Josh Billings
                  Law of Logical Argument - Anything is possible if you don't know what you are talking about.
                  Don't own anything you have to feed or paint. - Hood River Blackie


                  • #10
                    Don't use the indexer pin or you may break it or the pulley. I engage the back gear lever, stick the chuck key in one of the pinions and give a yank towards me. Don't put anything in the jaws and hammer. Use a piece of wood across two jaws and tap. Before I'd do that though, I'd use a rod in one of the pinions and hammer. Less chance of breaking out a jaw.


                    • #11
                      I do exactly what CCWKen does.

                      I am in general AGAINST hammering on things in a gear train, unless the gear train is as stout as the ones in machines CarlD is used to.

                      That Atlas ain't a Springfield. You actually have a pretty decent chance of breaking something on the Atlas. Not so on a Springfield, or other big-A heavy machine (substitute favorite big-A machine names as needed).

                      IMPACT cracks Atlas gears (and ones in other lightweight machines). A steady pull, even with a lever does not have as good a chance of breakage, so that is what I'd try if a good pull with the key isn't good enough.

                      P-Blaster is good stuff for stuck things.
                      3751 6193 2700 3517

                      Keep eye on ball.
                      Hashim Khan

                      If you look closely at a digital signal, you find out it is really analog......


                      • #12
                        I don't have the countershaft nor back gears on my lathe currently. I want the chuck off since it seems like a requisite for removing the spindle.

                        I tried putting some 3/4" oak in the jaws and striking it with a hammer.

                        I held the cone pulley with my hand and struck the oak with a 16 oz claw hammer. I did this repeatedly. I eventually broke the oak. The chuck didn't budge. I hosed it down with WD40 though I don't think it's going to do anything. Maybe it will find a way in, we'll see.

                        Stay Tuned.


                        • #13
                          When using a hammer, hitting a lot with a light one is not equal to a couple of good "clugs" with a big one......

                          if the gears are not in, you can't break them, so go for it, just don't damage the bearings, or bend the spindle by getting vicious on it.
                          3751 6193 2700 3517

                          Keep eye on ball.
                          Hashim Khan

                          If you look closely at a digital signal, you find out it is really analog......


                          • #14
                            I think I'll try a cheater bar and strap lock. I don't want to beat on it.


                            • #15
                              Threaded spindle noses & removing chucks....

                              The 2 lathes I have that use threaded spindle noses have both been subject to the "lock the spindle with the back gear" routine and the chucks come off fairly easily. It is the recommended method in the Atlas 6"/10" manual.

                              Yes, use a chuck board to protect your ways. 30 to 50 lb. chucks can hurt your fingers & bruise ways. Lathe beds don't heal well.

                              Never had a problem with the D1 spindle nose on the other lathe.

                              The SB wore it's 3 jaw for a number of years without removal; I just used a piece of 2 x 4 between 1 jaw & the bed and rotated the spindle by hand from the pulley. Banged a few times, but it came off. I can't recall if the back gears were in for torque multiplication or not though....