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Chinese 10x18 Lathe Spindle Noise - I think I know what's wrong?

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  • Chinese 10x18 Lathe Spindle Noise - I think I know what's wrong?

    Hey guys, my Craftex B2227L 10x18 lathe has given me grief since the day I got it (used) but the latest issue is a lot of spindle noise after running it for extended periods. I think I know the issue but I wanted to see if I could get a second opinion.

    The lathe relies in "splash lubrication" or something, basically the gearbox throws oil around when spinning. It does this fine, I've seen it.

    The issue seems to be that the spindle is lubricated by oil getting thrown up on the lid of the gearbox, some of it makes its way into a trough that runs around the edge of the box and into a hole above the front spindle bearing. I've marked it in a picture here;



    The trough is slightly sloped, seems to get oil in it as when I open the gearbox its usually filled up with oil.

    The lathe makes a lot of noise at low gears due to some poorly-made and improperly spaced gears for the low-end speeds, but the high speeds sound pretty smooth except this new sound after extended use. I think the spindle bearing is spinning out its oil or something and this drip system doesn't replenish it fast enough. After sitting for a day enough seeps in that it runs quiet again for a while until its all spun out again. There is a ball fitting above the hole in the top cover, I can squirt oil into there and that helps the sound a bit for about 10 seconds before its back again.

    Another possible cause, I replaced the original cover gasket which was soft rubber and terribly deformed, I took care to cut the new gasket to give clearance for the trough, and the cover has a recess inside which makes the edge that meets the gasket thinner than the edge on the gearbox, so I don't think it should interfere with the trough even without a gasket at all. But I could be wrong.

    The rear bearing has no such trough and so I think must be packed with grease.

    A guy with a similar lathe had a similar problem. He took his apart to find no grease, and bearings that were not happy. His unit doesn't have a gearbox like mine so I don't know what his lube situation is intended to be. http://users.picknowl.com.au/~gloami...9325rev-g.html

    Should I take my spindle out and pack the bearing with grease?

    After I do that should I plug the oil hole so oil and grease don't get mixed up?

    Thanks for any tips. Someday this lathe will work decent, I swear.

  • #2
    Hi Matt,

    I have the same lathe. One the top of the cover mine has an oiler that lines up with the hole for the bearing. I think this may have been added in newer lathes, but I'm not 100% sure.

    I oil it daily with AW hydraulic oil (same oil that i use in the headstock).

    Edit: I reread your post and you also have the oiler. On reading this I think the bearing maybe cooked. I know lots of people forget to oil this port as they put a tool tray on the top and cover up the oiler. Grease might work, but the oil really does splash around a lot in there. You could cut a small plastic shield to try to keep the grease in. Grease is a viable option for spindle lubrication.

    Gearbox is noisy, but comes with the territory.
    Last edited by enginuity; 12-07-2016, 12:21 PM.
    www.thecogwheel.net

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    • #3
      You may also want to check the preload before you take it all apart. Have you cut anything with the lathe?
      www.thecogwheel.net

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      • #4
        I was doing some substantial removal in hot roll steel when the issue started up. Bought the lathe used about a year ago, made in 2006. Didn't seem to have much use on it and the guy selling said he never used it much.

        I'm thinking if I block that oil trough route and grease the bearing, that would make for a good fix. I hope the bearing isn't cooked already.

        When you say check the preload do you mean check it before taking apart so I have an idea what it should be, or check that it's properly loaded to begin with? Either way don't know how to do that so I'd have to read up before tackling it.

        Lathe seems to be performing alright, only just started doing steel with it, but it seems to be having a hard time taking much off. 0.005" feed rate, 0.015" DOC, 350 RPM, 1.5" diameter hot roll steel after the scale is cleared, with oil, chips are coming off coloured. Using high speed steel with a pretty big nose radius, finish is alright but the heat has me surprised. My reading says the only thing that should affect DOC is horsepower, but I'm getting a lot of chip welding on the tip and its messing up the effectiveness pretty quick.

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        • #5
          Roller bearings do not need a LOT of oil, but they do need some. Just enough to carry off heat, lubricate the cages, and lube the rollers to take care of "scuffing". It's not a lot.

          Possibly the gears are not picking up and throwing off enough oil at high speeds.

          The 10 seconds of quiet after oiling is interesting.... suggests the oil is damping something and after much of it is slung off, the "something" is again not damped.

          Agree on preload.

          Put an indicator against the spindle nose. Stick a piece of wood down the spindle bore, and try to move the spindle around. You basically should not be able to do that, it should be in the low tenths at most (NOT the same thing as "accuracy", don't be confused).

          Move the indicator 90 deg, repeat.

          If you cannot move the spindle, that's good, but eliminates a source of noise. You might try it directly after the machine is turned off after it has been making the noise. If it is a heat expansion issue that will show it up.

          If you CAN move it noticeably, take up on the spindle nut until you just cannot move it. Give it oil and run to see if the noise remains.

          I somewhat suspect the noise could be from the heat expansion after running a while, which may loosen the preload and allow the spindle and inner cone/rollers to rattle around in the bearing race. Then the oil might damp down the spindle rattling for a bit, but not for long. Your previous work may have backed off the preload spindle nut due to vibration, etc just enough.

          In bad cases of that, where tight enough hot is stupid tight when cold, Belleville washers can help out, that's a standard use (if you have room and can get the right size). But odds are that yours can be adjusted i that is the issue.

          I'd think there must be a way to get more oil in, even the oiler fitting is not a great solution, it probably should have a feed. A collector plate feeding a second angled drilled hole into that vertical hole (careful with chips if you do that), or the like.

          I don't like grease that much especially when they seem to intend oil.
          Last edited by J Tiers; 12-07-2016, 01:13 PM.
          1601

          Keep eye on ball.
          Hashim Khan

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          • #6
            With chip welding, you're probably better off with a carbide cutting tool. I would replace the bearing and make sure the oil passages are clear. You will get better lubrication and cooling with circulating oil than with grease. Proper preload is important. Too little, and the spindle won't be solid. Too much and it will quickly overheat.
            Kansas City area

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            • #7
              The nuts that folks are talking about are the two ring nuts on the outboard end of the spindle in case you didn't know. If your tool kit does not include them take the time to make up a set of G wrenches so the slots do not get chewed up and keep them aside for next time. Don't be one of those folks that just uses a pinch punch.

              When checking for any play in the bearings watch the indicator dial for a sudden step that comes from moving through the range of play. This is quite different from looking at a smooth spring like travel that might occur from you just flexing the spindle.

              I tend to suspect that it's more of an issue of improper preload that opens up after the spindle warms up as mentioned above. You need a touch of preload on the bearings when cold so they remain at zero or slight preload when warm. It's a fussy sort of adjustment too. Be prepared to play with two and three degree adjustments of the nuts as they tighten up and the outer one takes up the play in the threads of the inner nut. Which is another good reason for taking the time to make the proper wrenches. If beaten up with a pin punch or pipe wrench the burrs won't allow you to perform the delicate adjustments to nail the preload as the rings tighten against each other.


              Your lathe should be able to take a way heavier DOC then .015. But a .005 (sure it wasn't .0005?) is a pretty heavy feed rate. The way the chips are welding to the tip suggest that you've gone past the sweet spot for the cutter geometry and you're plowing off more than it should and that is causing the heat and chip welding.

              I've found that running too much nose radius tends to alter the actual cutting corner and that it makes the cutter act suspiciously like a negative rake right at the nose. Perhaps try a smaller nose radius. Especially with a larger size nose radius and with some top rake and only a .015 DOC the metal will never see the straight portion of the cutter. It'll always be riding the trailing edge of the now lower than mid point nose radius. Been there got the shirt.... Since I found this I tend to err on the side of a very small nose radius and the tools seem to cut more cleanly. But HSS isn't a coated carbide. I also found that unless I was willing to live with big bird's nests of blue hot shavings that I needed to lower the feed speed. And in fact for anything other than longer cuts I just found it easier to feed by hand so I could interrupt the cuts to break the chips. And running by hand for the hogging cuts also allowed me to feel the cutter back through the handle and set a feed pressure that cut without excessive heating. Then I engage the feed for lighter sizing and finishing cuts for the even finish.
              Last edited by BCRider; 12-07-2016, 01:39 PM.
              Chilliwack BC, Canada

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              • #8
                I don't see any facility for adjusting preload in the pic.
                “I know lots of people who are educated far beyond their intelligence”

                Lewis Grizzard

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                • #9
                  Originally posted by Dave C View Post
                  I don't see any facility for adjusting preload in the pic.
                  I've yet to find a lathe that didn't have the spindle bearing adjustment ring nuts on the outboard end of the spindle.
                  Chilliwack BC, Canada

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                  • #10
                    Thanks guys, I'll do some fiddling around tonight, so far I've got;

                    1. Insert wood in spindle bore and try to push the spindle around, see what kind of deflection i can produce on an indicator, at different spindle positions
                    2. Check oil passage is clear. I'll try cleaning the trough and putting some oil in it, see if it flows. The lathe is almost level, but ever so slightly tilted towards the tailstock, shouldn't be an issue for the oil flow.
                    3. Start making a pair of G wrenches for the spindle nuts. Surely the preload is not well tuned as the previous owner of this lathe was an idiot and I'm sure the factory does the fastest job they possibly can. Hopefully it's all that's wrong.

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                    • #11
                      Nuts are in the box on the end

                      EDIT; to clarify the pic, I replaced a couple of bearings on the gear shafts because of noise, I thought I had it figured out that a bad bearing was on one of the shafts but it turned out the pair of gears on the spline that controls the high and low speed ranges are poorly made; the high speed gear meshes well but the low speed gear does not and makes a lot of shatter, especially when not under load.

                      Never touched the spindle shaft during that though. It's as it was when I got the lathe.

                      Last edited by mattthegamer463; 12-07-2016, 02:04 PM.

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                      • #12
                        Oh geez. You'll have to limit the length of the handles if you have to make your own.

                        On my lathe the "box" is also the movable part. So I can reach the adjustment nuts as well as all the rest with any length of wrench.

                        It would be an interesting mod to zip cut off and attach the top and front sides to the movable door. That would sure open up a lot of nice working room for reaching the spindle nuts and gear retention nuts.
                        Chilliwack BC, Canada

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                        • #13
                          Those are the nuts.

                          Most Chinese tools are set without enough preload on the spindle. It is safer and quicker this way for them as they don't have to monitor the spindle temperature before they ship the machine.

                          You should be able to take a lot more DOC. The RPM is fast for HSS, and that is the biggest problem with this lathe. The higher speeds are great for smaller stock, but larger stuff is just way too fast. Make sure you also check your tooling geometry.

                          For what it's worth, I've taken a 1/8 DOC with the same model lathe in steel. It's in the video on the concrete workbench on my blog.
                          www.thecogwheel.net

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                          • #14
                            Originally posted by enginuity View Post
                            Those are the nuts.

                            Most Chinese tools are set without enough preload on the spindle. It is safer and quicker this way for them as they don't have to monitor the spindle temperature before they ship the machine.

                            You should be able to take a lot more DOC. The RPM is fast for HSS, and that is the biggest problem with this lathe. The higher speeds are great for smaller stock, but larger stuff is just way too fast. Make sure you also check your tooling geometry.

                            For what it's worth, I've taken a 1/8 DOC with the same model lathe in steel. It's in the video on the concrete workbench on my blog.
                            Doesn't even seem to flinch with that cut. I need to get serious about angles on my HSS grinds, and watch more grinding videos.

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                            • #15
                              Matt, when grinding my HSS I'll finish up with just a slight kiss on the corner to put about a .01 bevel on the very corner. Then a couple of strokes with a triangle india stone I need handy at the lathe for this use and generally freshening up between grindings dubs off the corners of the bevel to give me a sort of .006 to .008 sort of nose radius. For general cutting use I found that much is enough to extend the time between grindings by a good amount without causing issues on finer cuts with the radius becoming too significant for the tool. And for finer finishing cuts I don't even kiss the corner on the grinder. I either leave it sharp or I might lightly hone in a very fine nose radius. And when I do it's mostly to remove a burr that I might feel.

                              The only times I use a bigger nose radius is if I'm deliberately wanting to leave a radius at the shoulder of a cut for stress reasons.
                              Chilliwack BC, Canada

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