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Puzzled by Atlas Mk. 2 back gear engagement

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  • Puzzled by Atlas Mk. 2 back gear engagement

    I've just acquired a 6" Atlas Mk. 2 lathe, from eBay. It is in fine shape, although all the gibs were loose. Adjusting these took out all the play in the carriage and cross-slide. The spindle bearings, and bed, seem fine.

    I cannot engage the back gears. http://www.lathes.co.uk/atlas/page14.html describes the procedure (which doesn't work for me):

    "At first sight there is no obvious way of releasing the large V pulley from its embrace with the spindle. The secret is the "external locking ring" on the end of the pulley; this is simply pulled outwards to uncouple it from the shaft and the backgear lever then operated as usual to mesh the respective gears."

    I've pulled backwards on the locking ring, first with my fingers, then with needle-nose pliers, but nothing budges, and the pulley remains keyed to the spindle.

    If any members have this lathe, and can describe what I should be doing, I'll be grateful.
    Allan Ostling

    Phoenix, Arizona

  • #2
    I am not familiar with that particular lathe, but if it has been sitting, or the previous owner did not use the backgear with any frequency, it is quite possible it is stuck or gummed up.

    I use Kroil but PB Blaster or a similar penetrant applied to the area with a little judicious tapping may help in freeing it up. If that does not work, it may be necessary to dismantle and clean the parts to make it operable. You might try to locate a parts & operating manual for the lathe before delving too deeply. Most Atlas machines are pretty straightforward in assembly.
    Jim H.

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    • #3
      thereis something very frustrating going on there , i cant remember how it is done , but is a very poor design , i will try and find out .

      I do remember a ****ty little ball bearing detent thing there that pops out on the floorgiven a chance-

      Comment


      • #4
        Originally posted by thistle
        thereis something very frustrating going on there , i cant remember how it is done , but is a very poor design , i will try and find out .

        I do remember a ****ty little ball bearing detent thing there that pops out on the floorgiven a chance-

        I saw that ball-bearing "detent." It is spring-loaded, and I assume it is a plug for an oiling port. I've thought about squirting some penetrating oil through it.

        It's possible that the back gears were seldom used, but I find it hard to believe the mechanism is seized so apparently tight, in a lathe which is otherwise in good condition. I will be eager to learn the procedure, once you try it on your lathe.
        Allan Ostling

        Phoenix, Arizona

        Comment


        • #5
          The little six inch Atlas has a pin with a detent ball and spring that when in the "in position" locks the drive pully to the spindle. When in the out position, the pully will be free turning around the spindle. To put the lathe in back gear locate this small pin on the right side of the pully and pull it out to the "out position". Then engage the back gear lever and you are ready to go. The pin I am talking about is small and in an obscure place if you don't know where to look. It is on the right side of the spindle pully at the front of the headstock. The pin is about a 1/4" dia. and moves back and forth on the same axis as the carriage on the ways. Good luck!

          Perk in Cincinnati

          Comment


          • #6
            Originally posted by eperkins
            The little six inch Atlas has a pin with a detent ball and spring that when in the "in position" locks the drive pully to the spindle. When in the out position, the pully will be free turning around the spindle. To put the lathe in back gear locate this small pin on the right side of the pully and pull it out to the "out position". Then engage the back gear lever and you are ready to go. The pin I am talking about is small and in an obscure place if you don't know where to look. It is on the right side of the spindle pully at the front of the headstock. The pin is about a 1/4" dia. and moves back and forth on the same axis as the carriage on the ways. Good luck!

            Perk in Cincinnati

            There is no such pin on the Mark 2 version of the 6" Atlas. The procedure is entirely different. If you go to my original post and click on Tony's link, you'll see the procedure as it is suppose to work. Unfortunately, it doesn't for me.
            Allan Ostling

            Phoenix, Arizona

            Comment


            • #7
              I think if a few soakings of penetrating oil doesn't free it up you'll have to disassemble- it should pull out effortlessly with just your fingertips. Some times you need to wiggle the chuck a little to push it back but never to pull it out.

              Comment


              • #8
                Originally posted by jmm360
                I think if a few soakings of penetrating oil doesn't free it up you'll have to disassemble- it should pull out effortlessly with just your fingertips. Some times you need to wiggle the chuck a little to push it back but never to pull it out.
                I have an exploded parts drawing, but no instructions on disassembly. If anybody has disassembled the headstock, I'd be grateful for advice.
                Allan Ostling

                Phoenix, Arizona

                Comment


                • #9
                  I may be looking at this wrong,

                  But what I see, is that the part to be pulled should be the small collar around the snap ring, The snap ring appears to be on the spindle itself, holding what looks to be a bearing Which means that you'd pull the collar around it, looking at the rear view of the photo, you have the pulley, a small gap, a collar, then the spindle and snap ring.

                  looking at the cad drawing, it seems that it's one bit with the pulley, but looking at the the photo it doesn't.

                  ken.

                  Comment


                  • #10
                    Originally posted by kendall
                    But what I see, is that the part to be pulled should be the small collar around the snap ring, The snap ring appears to be on the spindle itself, holding what looks to be a bearing Which means that you'd pull the collar around it, looking at the rear view of the photo, you have the pulley, a small gap, a collar, then the spindle and snap ring.

                    looking at the cad drawing, it seems that it's one bit with the pulley, but looking at the the photo it doesn't.

                    ken.
                    I think you are correct. The Atlas instruction manual states that the procedure is to pull on the small collar (which is referred to as a coupling) -- "Pull coupling (A figure 7) to disengage pulley and gear" is how it is phrased. There is a arrow identifying "A" as the collar of which you speak.

                    But the collar won't budge either. In fact, that was what I tried first, pulling on this collar with needle-nose pliers after manipulation by hand failed.

                    Disassembly is not obvious. I wonder if there are press fits, perhaps needing a special gear puller?
                    Allan Ostling

                    Phoenix, Arizona

                    Comment


                    • #11
                      Sorry I should have read your question more carefully,
                      It's not the snap ring you pull on, like kendall said it's the piece surrounding it, about 1 3/8" OD. It's nested inside the pulley, the pulleys do not move laterally. It doesn't show in your CAD drawing, in the lates.co photo it's the shiny ring.
                      John

                      Comment


                      • #12
                        Originally posted by kendall
                        But what I see, is that the part to be pulled should be the small collar around the snap ring, The snap ring appears to be on the spindle itself, holding what looks to be a bearing Which means that you'd pull the collar around it, looking at the rear view of the photo, you have the pulley, a small gap, a collar, then the spindle and snap ring.

                        looking at the cad drawing, it seems that it's one bit with the pulley, but looking at the the photo it doesn't.

                        ken.
                        I've found an eBay auction for the spindle, which has a photo shedding some light on the situation: http://cgi.ebay.com/ATLAS-CLAUSING-6...QQcmdZViewItem

                        This seller has another auction for the coupling, which is what is apparently jammed on my spindle shaft.

                        Assuming my coupling is jammed, it looks like disassembly could not proceed without UNjamming the parts.

                        I shall consider bidding on this sellers items.
                        Allan Ostling

                        Phoenix, Arizona

                        Comment


                        • #13
                          Originally posted by jmm360
                          I think if a few soakings of penetrating oil doesn't free it up you'll have to disassemble- it should pull out effortlessly with just your fingertips. Some times you need to wiggle the chuck a little to push it back but never to pull it out.
                          I'm in a quandry, as to how to disassemble. I can remove the outermost retaining ring, but that serves only to allow the collar (coupling) to slide off the back end of the spindle. This doesn't free the collar, which is frozen to the spindle, and I don't see how I can bust it loose. I can't get a grab on the collar O.D., because it nests inside the I.D. of the spindle drive pulley (shown in an eBay photo here: http://cgi.ebay.com/ATLAS-CLAUSING-6...QQcmdZViewItem ). There is room for me to grap the collar with pliers, but that's all.

                          I'll try more penetrating oil, and wait for inspiration.
                          Allan Ostling

                          Phoenix, Arizona

                          Comment


                          • #14
                            Remove the snap ring, and apply good penetrating oil. Let it soak for a while, it might be a good idea to stand the lathe on end so the penetrating oil will get into the proper area.

                            Sometimes, the part can be tapped and pried, and moved small distances at a time until it is finally worried loose. There should not be any need for specialized tooling that I can see. As I mentioned, assembly is usually pretty simple. Even if you were to purchase replacement parts, you will still have to dismantle it. Once apart, cleaning and lubrication will more than likely solve the problem.
                            Jim H.

                            Comment


                            • #15
                              Originally posted by JCHannum
                              Remove the snap ring, and apply good penetrating oil. Let it soak for a while, it might be a good idea to stand the lathe on end so the penetrating oil will get into the proper area.

                              Sometimes, the part can be tapped and pried, and moved small distances at a time until it is finally worried loose. There should not be any need for specialized tooling that I can see. As I mentioned, assembly is usually pretty simple. Even if you were to purchase replacement parts, you will still have to dismantle it. Once apart, cleaning and lubrication will more than likely solve the problem.
                              My can of penetrating oil is probably thirty years old, so the first thing I am going to do on the way home from work tonight is get a new can. I like your advice, and will stand the lathe on end to let the oil soak in.

                              The seller of the lathe (which belonged to his father) is being very helpful. He kept the ways and slides lubricated while it was in storage in Florida, but the high humidity may account for the collar/coupling being frozen to the spindle shaft.
                              Allan Ostling

                              Phoenix, Arizona

                              Comment

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