Announcement

Collapse
No announcement yet.

3 Jaw Chuck Issues

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    I think he has two problems.

    He said that the issue has gradually become worse, and things in the chuck seem to be crooked. So there is reason to believe in a chuck issue.

    The spindle issue is different. Or appears to be, from his statements, anyway. Many of us have said, 0.003" spindle runout is a TON of runout, and that is so. The old Logan has only about 0.0006" TIR runout on any part of the spindle, and I would expect that even with a Grizzly/BusyBee/harbor freight chinese machine, one would expect, and get, under 0.001" TIR.

    Rolling bearings (ball or roller) should not "wear out". Over many years of heavy usage, the rollers or balls may fatigue and start to spall, but if the balls or rollers actually "wear", they must be getting abrasive grit in them.
    2801 3147 6749 8779 4900 4900 4900

    Keep eye on ball.
    Hashim Khan


    It's just a box of rain, I don't know who put it there.

    Comment


    • #17
      I bought a very cheap long nose pneumatic die grinder on ebay and it is better than expected.
      Ebay no 239196340919

      Comment


      • #18
        Originally posted by J Tiers View Post
        I think he has two problems.

        He said that the issue has gradually become worse, and things in the chuck seem to be crooked. So there is reason to believe in a chuck issue.

        The spindle issue is different. Or appears to be, from his statements, anyway. Many of us have said, 0.003" spindle runout is a TON of runout, and that is so. The old Logan has only about 0.0006" TIR runout on any part of the spindle, and I would expect that even with a Grizzly/BusyBee/harbor freight chinese machine, one would expect, and get, under 0.001" TIR.

        Rolling bearings (ball or roller) should not "wear out". Over many years of heavy usage, the rollers or balls may fatigue and start to spall, but if the balls or rollers actually "wear", they must be getting abrasive grit in them.
        Agreed. The place to start though is with why that spindle has so much runout. I have a jet 13x40 lathe and its runout is maybe a couple tenths at most. Way back I had one of the famous china 7x10 lathes, that was WELL under .001 also. Brian's .003 is either a indication of a manufacturing defect from when it was new (assuming it was that bad when new) or a serious problem with the bearings, their mounting (spun on shaft/housing etc) or the spindle itself developed a problem (bent from crash etc).

        The chuck may well be a problem also but the spindle is the place to start searching for problems. Maybe Brian will recheck his measurements, .003 on the spindle is so bad its hard to believe.

        Comment


        • #19
          It will be almost impossible to get any chuck running correctly, no matter how expensive it is without the spindle being ok. I have two Chinese 160mm chucks, and they run well enough for three jaw scroll types. All the testing of the spindle has been mentioned in this thread. Even if the adjustment of the spindle bearings was out, just rotating the spindle against a dti would not show it up, so my money is on the flange needing a slight skim.

          Comment


          • #20
            Originally posted by Sparky_NY View Post

            The chuck may well be a problem also but the spindle is the place to start searching for problems. Maybe Brian will recheck his measurements, .003 on the spindle is so bad its hard to believe.
            Yes, and definitely agreed on the runout being beyond ridiculous for a decent metal lathe. (would be invisible on a wood lathe). Correcting the chuck will need to wait until there is a reasonable base to begin it.

            I was more discouraging replacing the chuck before investigation of the (likely) two problems.

            We need to see exactly where he measured, and what the result was each place.

            If measured inside the taper, that would be obnoxious, but not a problem using the chuck.

            If measured on the unthreaded portion, that would suggest a problem with the chuck mounting means.... it's difficult to measure on the threads (but do-able), so measuring on the outside of the chuck is a possible for confirmation. If the error is repeated on the OD of the chuck, for position and general amount, then it looks bad for the spindle.

            I'd like to see a measurement on the face of the spindle mount as well, to eliminate "cam runout" in the chuck problem. That at least, could be swarf etc under the chuck as mounted.
            2801 3147 6749 8779 4900 4900 4900

            Keep eye on ball.
            Hashim Khan


            It's just a box of rain, I don't know who put it there.

            Comment


            • #21
              Brian, where did you measure the spindle runout?

              Comment


              • #22
                I removed the chuck and checked the runout on the outer diameter of the flange on the spindle. This outer diameter fits into a register in the back side of the chuck. I checked over my notes that I made when the lathe was brand new, and it had 0.002" total indicated runout fresh out of the box.
                Brian Rupnow
                Design engineer
                Barrie, Ontario, Canada

                Comment


                • #23
                  Originally posted by brian Rupnow View Post
                  I removed the chuck and checked the runout on the outer diameter of the flange on the spindle. This outer diameter fits into a register in the back side of the chuck. I checked over my notes that I made when the lathe was brand new, and it had 0.002" total indicated runout fresh out of the box.
                  That is horrible for a new machine but it would be interesting to measure the runout on the ID taper of the spindle. It "should" be the same as the OD but there is only one way to be sure. Spindle runout is customarily measured on the ID taper of the spindle. It would also be interesting to see what the QC sheet with the lathe "claims" the runout was when tested at the factory, my bet is less than 1/4 what you measured.

                  Can you measure the runout at the other end of the spindle to see if its similar? That would be a interesting data point.

                  More data never hurts and will help determine a plan of action.

                  Comment


                  • #24
                    Update ! Google searching to see if I could find any other reported problems with runout on this lathe AND found Brians post when he first got the lathe ! He posted .002 runout AT 2" out from the 3 jaw chuck ! The pic clearly shows this was not done with something like ground stock but rather what looks like a piece of raw brass. Nothing says the brass is round !!! Also, the runout includes the chuck, its not a measurement at the spindle itself.

                    I say his original measurement was invalid. I'm not knocking Brian, this may well be a good thing ! The runout when new may well have been much better than what he thought, especially inside the spindle.
                    Yesterday I brought home my new CX701 lathe from BusyBee Tools in Barrie. This is their new offering with 1.5 HP variable speed D.C. 90 volt motor, which...

                    Comment


                    • #25
                      Originally posted by Sparky_NY View Post

                      That is horrible for a new machine but it would be interesting to measure the runout on the ID taper of the spindle. It "should" be the same as the OD but there is only one way to be sure. Spindle runout is customarily measured on the ID taper of the spindle. It would also be interesting to see what the QC sheet with the lathe "claims" the runout was when tested at the factory, my bet is less than 1/4 what you measured.

                      Can you measure the runout at the other end of the spindle to see if its similar? That would be a interesting data point.

                      More data never hurts and will help determine a plan of action.
                      +10 on all of this!
                      2801 3147 6749 8779 4900 4900 4900

                      Keep eye on ball.
                      Hashim Khan


                      It's just a box of rain, I don't know who put it there.

                      Comment


                      • #26
                        If that runout is measured on the OD of the flange, does that not give you a way of setting the chuck in one of either 3 or 4 positions- one of which should give the chuck jaws the least amount of runout? Or is there only one orientation in which it can mount? I'm assuming it's the backing plate that has the recess to fit over this flange- if so, then the chuck to backing plate interface is also a potential trouble spot.

                        I'm hoping that the face of the flange is running true- there should be no detectable runout there, and if there's a register surface in front of the flange, there should be well under a thou of runout there. If your spindle bore has a morse taper, you should also be reading well under a thou at that point. My 8x18 showed just under 2 tenths in all these areas, last time I checked anyway, which was many years ago. It would be good for you to spend some time checking out your spindle before doing anything to a chuck except a rebuild for cleaning.
                        I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                        Comment


                        • #27
                          I cannot comment on Mr Rupnow's equipment because I have not seen or examined it. That said , I have bought a
                          few items sold by Busy Bee tools.
                          Some of them have worked well for me, some have been disappointments.
                          When I moved I gave my 13 by 36 Busy Bee lathe to my apprentice. I used it for some 20 odd years but never really liked it.
                          His Dad , a very capable machinist, says it is a useable but not a good tool.
                          I recently bought a small rotary table from Busy Bee to use on my Atlas Horizontal mill. This morning I got my 40 divisions allright,( Long story there) but again did not enjoy the " Feel" of it and have doubts about using it for small gear making.
                          All in all, I feel that buying Asian made equipment is akin to gambling, sometimes you win, sometimes you loose and often you are tempted by the glitz and glamour of new and exciting.
                          Regards David Powell.

                          Comment


                          • #28
                            Originally posted by brian Rupnow View Post
                            Runout on the spindle, as checked without the chuck in place is still +/- .003 total indicated runout.
                            you measured on a registery taper - i.e. either D1 mount or internal taper? that is nuts. wow. its either been crashed, the spindle wasn't made properly or they used pebbles instead of ball bearings.....or maybe the nuts putting the preload on have come loose (should never happen, but can't think of what else it could be). put a tenths indicator on the spindle and try applying a radial force - press it back and forth. Do you see any flex?

                            Forget about the chuck, the problem is the spindle.
                            in Toronto Ontario - where are you?

                            Comment


                            • #29
                              I have a feeling that the spindle nose is similar to the design on the 7 x 10 lathes. I would like to see a picture of it.

                              Comment


                              • #30
                                Your 0.003" is in the spindle. The inconsistency MAY be in the chuck, but as has been said and repeated, figure out the spindle first.

                                I sort of doubt you hae seriously loose preload, because I have had that, and absolutely NO turning could be done without ridiculous amounts of chatter, and a horrible finish. The finish you get seems fine, and you have not mentioned chatter.

                                So the spindle may be just horribly badly made. But without measurements and pictures of the setup for them, we have no way of knowing,.
                                2801 3147 6749 8779 4900 4900 4900

                                Keep eye on ball.
                                Hashim Khan


                                It's just a box of rain, I don't know who put it there.

                                Comment

                                Working...
                                X