Are my lathe's spindle bearings out of whack?
Close
Login to Your Account
Results 1 to 15 of 15
  1. #1
    Join Date
    Feb 2018
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    6
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default Are my lathe's spindle bearings out of whack?

    Hello all,

    I've recently acquired a Logan 1825 that was an old shop class lathe and has taken some love to get cleaned up and running. I noticed that I was getting some wobble on my workpiece so I've been trying to track down the cause. After putting my dial indicator on the outside of my chuck I found that it wobbles about 4 thou. I pulled it off and put my dial on the spindle just above the treads where it's flat and it's off about 0.6 - 0.8 thou.

    Is this enough of a misalignment that I should be concerned?

    Would this be a bearing issue? Damaged spindle?
    How do I tell?

    I'm still climbing that learning curve so drawing it out in crayon is much appreciated.
    Thank you!

  2. #2
    Join Date
    Sep 2015
    Country
    UNITED STATES
    State/Province
    California
    Posts
    161
    Post Thanks / Like
    Likes (Given)
    12
    Likes (Received)
    63

    Default

    Put the chuck back on and set up a dial indicator on top of it. Then using a 2x4, gently pry up on the chuck to see if the indicator reads it moving up and down. You can also check the end-play of the spindle this way. Lateral and/or axial movement of the spindle typically indicates bearing failure.

  3. #3
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    3,756
    Post Thanks / Like
    Likes (Given)
    72
    Likes (Received)
    615

    Default

    If you making table legs out of wood then it might be acceptable. Otherwise forget it. "oh my poor bearings".

    For a reference, a Hardinge lathe runout is +/-.000025.

  4. #4
    Join Date
    Aug 2003
    Location
    Eureka, CA, USA
    Posts
    1,634
    Post Thanks / Like
    Likes (Given)
    345
    Likes (Received)
    246

    Default

    Personally, I wouldn't give up on the old Logan without first adjusting the spindle bearings. (A Logan can't be a Hardinge even if touched by a fairy wand at midnight, so don't presume that .000025 runout is even remotely possible for your lathe. Quadruple that and you'll be in the ball park.)

    Adjustment procedures differ depending on the type of bearings your machine has but there's a fifty-fifty chance that you can improve that runout with a bit of work, given the lathe's history.

    Do some internet research on adjustment procedures before diving into this, however. It's ALWAYS possible to make a poor situation worse !

    P.S. When measuring spindle runout, the usual practice is to measure the internal morse taper. Make sure that the taper is clean and free of dings.

  5. #5
    Join Date
    May 2003
    Country
    UNITED STATES
    State/Province
    Iowa
    Posts
    9,827
    Post Thanks / Like
    Likes (Given)
    3005
    Likes (Received)
    3668

    Default

    First of all, I'm lefthanded also

    2nd What are you using for an indicator? If you don't have a "tenths" indicator, you're probably just seeing dings in the spindle.

    3rd. 4 thou on the OD of a chuck means very little. It's the OD of the chuck and nothing more. In fact, that's really pretty close.

    4th. You "newbies" tend to think you need to check everything before making any chips. Put a piece of steel in the chuck and turn the diameter down. If you can't take a 0.030" DOC without a bunch of chatter, then start looking for stuff.

    Don't look for problems where there are probably none.
    JR

  6. Likes tdmidget, JohnEvans liked this post
  7. #6
    Join Date
    Aug 2003
    Location
    Eureka, CA, USA
    Posts
    1,634
    Post Thanks / Like
    Likes (Given)
    345
    Likes (Received)
    246

    Default

    Quote Originally Posted by IAmTheSouthpaw View Post
    ...I noticed that I was getting some wobble on my workpiece...

    I think that he's suggesting that there is a problem (although he wasn't very specific) ?

  8. #7
    Join Date
    Feb 2018
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    6
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Quote Originally Posted by Spruewell View Post
    Put the chuck back on and set up a dial indicator on top of it. Then using a 2x4, gently pry up on the chuck to see if the indicator reads it moving up and down. You can also check the end-play of the spindle this way. Lateral and/or axial movement of the spindle typically indicates bearing failure.
    I did this and with medium pressure on 3 foot 2x4 it moves about 3-4 thou. but returned to almost the same location. I rotated over to the "low" spot and gave a little more pressure. Now it's only out about 2 thou. There is no obvious lateral movement.
    Should I keep prying with the 2x4 and try to get it close?
    Is this an indication that the spindle is damaged?
    What would you do next?

    Thanks Spruewell

  9. #8
    Join Date
    Jul 2003
    Location
    savannah, jaw-ja
    Posts
    1,513
    Post Thanks / Like
    Likes (Given)
    797
    Likes (Received)
    303

    Default

    Then there's the most likely clapped out old three jaw that's been crashed a few times in shop class holding the work that is "wobbling".

    Edit - the 2x4 test is just to see how much movement there is, not to bend anything! Note the word "gently" before the word "pry".

  10. Likes dalmatiangirl61 liked this post
  11. #9
    Join Date
    Feb 2018
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    6
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    There is a bit of surface rust on the inside of the taper. Would a brass brush be too aggressive? Would a brass brush be too aggressive on the ways?

    I'll clean out the taper and measure again.

    Thanks Randyc

  12. #10
    Join Date
    Feb 2018
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    6
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Quote Originally Posted by JRIowa View Post
    First of all, I'm lefthanded also
    ...
    JR
    1) Being left handed is hard, we're the only people in our right minds.

    2) Starrett 656, it does have a "tenths" indicator.

    3) I was thinking that it may just be the chuck, but it's nice to be reassured.

    4) I love this lathe. It has also been sitting for a good long while. I had to push through a solid layer of hardened crem in the apron plug.

    I've turned some aluminum which went pretty nicely, but later noticed the wobble and started hunting. If you think that it's pretty close then I may just be hunting snipes.

    Thanks JRIowa

  13. #11
    Join Date
    Feb 2018
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    6
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Quote Originally Posted by Rudd View Post
    Then there's the most likely clapped out old three jaw that's been crashed a few times in shop class holding the work that is "wobbling".

    Edit - the 2x4 test is just to see how much movement there is, not to bend anything! Note the word "gently" before the word "pry".
    Good call. That's what I thought but just wanted to double check before I did any real damage.

    You are absolutely correct in assuming the chuck has been hit.
    There is obvious damage on the compound rest where it's been run into the chuck by a teacher (students wouldn't dare!). The chuck has been replaced but the strike may have thrown the bearings out of alignment?

    In hindsight I should have included this little detail in the original post, my bad.

    Thanks Rudd

  14. #12
    Join Date
    Feb 2018
    Country
    UNITED STATES
    State/Province
    Utah
    Posts
    6
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Quote Originally Posted by randyc View Post
    Personally, I wouldn't give up on the old Logan without first adjusting the spindle bearings.
    ...
    P.S. When measuring spindle runout, the usual practice is to measure the internal morse taper. Make sure that the taper is clean and free of dings.
    I cleaned out the taper and measured the runout again. Luckily the hand on my dial indicator landed right on a tick mark because I could barely tell when it moved when I turned the spindle. I'm going to assume this is good

    Thanks Randyc

  15. #13
    Join Date
    Jan 2011
    Location
    BFE Nevada/San Marcos Tx
    Posts
    98
    Post Thanks / Like
    Likes (Given)
    82
    Likes (Received)
    47

    Default

    Coming from a school, anything is possible, even a bent spindle. Yes a brass brush is fine for cleaning out spindle, and on ways.

  16. #14
    Join Date
    Aug 2003
    Country
    UNITED STATES
    State/Province
    New York
    Posts
    92
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    10

    Default

    Iamthe southpaw,
    Your indicator (starrett 656) is graduated in thousandths or .001" increments. Generally when someone here mentions "tenths" they are referring to tenthousandths or .0001" and not .01" which would be 1/10 of an inch. If your lathe has tapered roller bearings in the headstock you should be able to tighten them a little to reduce that deflection with the 2 x 4. Light pressure, with the 2 by is important, remember that. Do not over tighten the bearings. Should you adjust the bearings be sure they are lubricated well and watch for excessive heat. Enjoy your toy. Oh yeah, I'm in my right mind as well...

  17. #15
    Join Date
    May 2003
    Country
    UNITED STATES
    State/Province
    Iowa
    Posts
    9,827
    Post Thanks / Like
    Likes (Given)
    3005
    Likes (Received)
    3668

    Default

    Quote Originally Posted by IAmTheSouthpaw View Post
    1) 2) Starrett 656, it does have a "tenths" indicator.
    The 656 is a travel indicator. Save up some money and get an Interapid 312-B
    http://www.metronprecision.com/Merch...jpgammaadj.jpg
    60 thousands travel, shock resistant, and auto reverse.

    OK, back to the lathe. Mos used 3 jaw chucks are probably junk by the time your get them. New, they usually aren't much better. The one I have and rarely use probably has 0.003" runout with the jaws re-cut. If you want accuracy, get a 4-jaw chuck. So many guys are scared of them because they really don't know how to use them. If you use one enough, you can put a piece of round stock in and have running within 0.001" in less than 10 minutes.
    JR


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •