Lathe spindle not very smooth.
Close
Login to Your Account
Results 1 to 19 of 19
  1. #1
    Join Date
    Apr 2018
    Country
    CANADA
    State/Province
    British Columbia
    Posts
    65
    Post Thanks / Like
    Likes (Given)
    25
    Likes (Received)
    7

    Default Lathe spindle not very smooth.

    Hey all,

    I have a 2010 model grizzly type 14x40 lathe. same quality, different name. actually fairly nice machine for the money.

    my question is in regards to how much force it takes for the spindle to turn ( in neutral).

    For instance, some machines spindles will glide very smooth with even a light touch - this machine will glide a little, but it definitely slows down, and has much more resistance then some machines.

    Can this be adjusted with the screw collars on the end of the spindle, or is it due to the lower quality bearings used in the imports? the spindle is very stout and has no runout.

    I have seen some imports with very smooth spindles, maybe I just got unlucky.

    Im running new AW46 oil in the gear box.

    thanks for any input.

  2. #2
    Join Date
    Jan 2009
    Location
    Maine, USA
    Posts
    203
    Post Thanks / Like
    Likes (Given)
    100
    Likes (Received)
    92

    Default

    The bearing preload as well as the seals will cause drag. It should still be smooth rolling, not crunchy or anything, but it may drag. Many manufactures specify the preload be set by adjusting the spindle nuts so after spinning the chuck with a good spin it comes to a stop within just a couple of rotations. It depends on the lathe. The other criteria is if the bearings/oil get too warm when running in high speed. Too tight and they will heat up.

    If it doesn't overheat and works well now, I certainly would not loosen the bearing preload. The performance of the machine will undoubtedly get worse if you do that.

  3. Likes hanermo liked this post
  4. #3
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    16,639
    Post Thanks / Like

    Default

    Take your HF $9.99 angle grinder, and engage the spindle.

    Reach in and grind the spindle smoother for better engagement.

  5. Likes g-coder05 liked this post
  6. #4
    Join Date
    Apr 2018
    Country
    CANADA
    State/Province
    British Columbia
    Posts
    65
    Post Thanks / Like
    Likes (Given)
    25
    Likes (Received)
    7

    Default

    Quote Originally Posted by digger doug View Post
    Take your HF $9.99 angle grinder, and engage the spindle.

    Reach in and grind the spindle smoother for better engagement.
    Sorry , im not following....can you elaborate?

  7. #5
    Join Date
    Jan 2009
    Location
    Maine, USA
    Posts
    203
    Post Thanks / Like
    Likes (Given)
    100
    Likes (Received)
    92

    Default

    He's pulling your leg because your machine is borderline against the rules here, trust me you don't want him to elaborate.

  8. Likes Milacron, eKretz, redlee, Joe Rogers, awake liked this post
  9. #6
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    8,481
    Post Thanks / Like
    Likes (Given)
    2047
    Likes (Received)
    5895

    Default

    Quote Originally Posted by Cleancut View Post
    Sorry , im not following....can you elaborate?
    Digger is being Digger, a swat with a rolled-up newspaper will send him on his way.

    If your machine is running OK as-is (headstock not overheating at the RPM/time you use it for), then leave it alone. If it's got real issues (overheating, noise, roughness when turning) then it could be investigated and a fix attempted.

    BTW, I also have a CN import 14 x 40, and it's not a bad machine for the money, except for an oil leak from the headstock past a seal on the power feed output shaft. I live with it for the moment, but at some point will cap it off when I convert to CNC operation.

    I'm mostly doing that so I can post a progress thread here to drive the other members batty.

  10. Likes JCByrd24, Cleancut, mike 44 liked this post
  11. #7
    Join Date
    Mar 2005
    Country
    UNITED STATES
    State/Province
    Indiana
    Posts
    4,442
    Post Thanks / Like
    Likes (Given)
    1065
    Likes (Received)
    963

    Default

    Leave it alone. If you don't know what you're doing you will mess up your spindle bearings.

  12. #8
    Join Date
    Sep 2009
    Location
    barcelona, spain
    Posts
    2,436
    Post Thanks / Like
    Likes (Given)
    549
    Likes (Received)
    1454

    Default

    To OP:
    You got "snarked" with the angle grinder comment.

    Posters here sometimes growl at import machines, even in the 14x40 industrial class that is fine for this forum.

    Your machine probably has generic bearings, a so-so spindle in terms of size // bearing fits and spindle straightness, and poor seals that add excessive friction.
    Most-all new lathes today have +/- exactly the same and function fine.

    If Your spindle has the common 2-nuts-on-thread spindle load and locknut, it is very unlikely you can do anything to improve the situation easily, without lots of work and or some components cost.

    And whatever You did, it would make Your lathe worse not better, via reduced preload, unless You address the core issues.

    Core:
    1.
    Better bearings would make the spindle run better, usually much better.

    -- These do not really need to be uber expensive machine tool bearings.
    Most import lathes are fit with bearings in a class with tractor trailers.
    They still work fine.
    Modern precision ac bearings from any industrial supply are likely to be a lot better.

    This is not very hard to do, but is not very easy, and may be quite a bit of work or not depending on gearbox stuff.

    1.1
    Minor spindle fitting might be necessary, or not.
    V-blocks, indicators, mics, will show it. Surface plate, reference std, 2 hours.

    Minor hand work and lapping with rigid laps, note rigid, adjusted via screws // controlled manner, may/can easily improve the spindle geometry 10-fold in a few hours.

    1.2
    Bearing bores might be good, or not.
    In size, and in alignment, and bores may have twists or no clearance at the inside radius.
    Or less than flat mounting surfaces or end stop surfaces.

    Not difficult to make a fixture to measure both bores at once, in both radius and at end surfaces.
    High precision linear rod (guide), v blocks, 4 x 2 micron dtis.

    2.
    Seals.
    Non-contact zero-friction labyrinth seals are available cheap, about 40$.
    See Nilos rings.

    3.
    Fit the reworked spindle and the better bearings and the new seals into the machine.
    You now have the worlds best 14x40 generic import lathe.
    Congrats !
    Similar in basic runout to the discontinued Grizzly ultra-precision 1 -micron tir machine at 40.000$, then 30.000$.

    BUT, except...
    4.

    After running-in the bearings, grind and/or rigid lap the spindle surfaces to run true.
    This is the most critical part !

    Even crap bearings repeat pretty well.
    This is why the import lathes work ok, since the spindle runs pretty true, after the mounting surface is trued running in it´s own bearings.

    SKF, Timken, et al allude to this in their MT spindle bearing literature.

    ?? See what it takes ?

    It is not difficult as such.
    It is involved.

    And laborious, as a one-off artesanal industrial high-accuracy job.

  13. Likes Cleancut, ptsmith liked this post
  14. #9
    Join Date
    Sep 2009
    Location
    barcelona, spain
    Posts
    2,436
    Post Thanks / Like
    Likes (Given)
    549
    Likes (Received)
    1454

    Default

    Good for You.

    Quote Originally Posted by Milland View Post


    I'm mostly doing that so I can post a progress thread here to drive the other members batty.

  15. #10
    Join Date
    Oct 2005
    Location
    dexter mich
    Posts
    284
    Post Thanks / Like
    Likes (Given)
    12
    Likes (Received)
    69

    Default

    Is this new not run yet ? or has it been running . Most likely Chinese . Short story Bought a 18x60 3 1/8 " inch metric lathe no name Chinese lathe ,it arrived and I put gear shift between gears [ verified by turning drive belts ] Put the chuck key in the chuck and tried to turn spindle , then tied harder , and harder , I said either I going to bend something or brake and pulled yet harder , it finally barely started to turn not well both directions the more it moved the freer it got this is back and forth . eventually it went lump lump .
    What had happened is called false brinelling . When a bearing is not rotated but is subjected to enough vibrations for long enough the oil is warn away and the balls and races they will corrode because they are being scrubbed clean they build up piles of rust around the roller or ball . I got the mfg to give me all new spindle bearing if I would install . These bearings are pretty large rollers with tapered bore for setting clearance preload . I bit of a good big chunk to chew I got a 16" 6 jaw thrown in and a discount on a large first order of tooling . The other thing I got out of it was an interesting education which had a price . The machine I have very few complaints about do to the price made it affordable for should not be spending this money budget .
    If it has been running tight spindle not so good .
    if it is new I would document it and discuss with dealer .
    I would not recommend doing it your self .

  16. #11
    Join Date
    Apr 2018
    Country
    CANADA
    State/Province
    British Columbia
    Posts
    65
    Post Thanks / Like
    Likes (Given)
    25
    Likes (Received)
    7

    Default

    Quote Originally Posted by hanermo View Post
    To OP:
    You got "snarked" with the angle grinder comment.

    Posters here sometimes growl at import machines, even in the 14x40 industrial class that is fine for this forum.

    Your machine probably has generic bearings, a so-so spindle in terms of size // bearing fits and spindle straightness, and poor seals that add excessive friction.
    Most-all new lathes today have +/- exactly the same and function fine.

    If Your spindle has the common 2-nuts-on-thread spindle load and locknut, it is very unlikely you can do anything to improve the situation easily, without lots of work and or some components cost.

    And whatever You did, it would make Your lathe worse not better, via reduced preload, unless You address the core issues.

    Core:
    1.
    Better bearings would make the spindle run better, usually much better.

    -- These do not really need to be uber expensive machine tool bearings.
    Most import lathes are fit with bearings in a class with tractor trailers.
    They still work fine.
    Modern precision ac bearings from any industrial supply are likely to be a lot better.

    This is not very hard to do, but is not very easy, and may be quite a bit of work or not depending on gearbox stuff.

    1.1
    Minor spindle fitting might be necessary, or not.
    V-blocks, indicators, mics, will show it. Surface plate, reference std, 2 hours.

    Minor hand work and lapping with rigid laps, note rigid, adjusted via screws // controlled manner, may/can easily improve the spindle geometry 10-fold in a few hours.

    1.2
    Bearing bores might be good, or not.
    In size, and in alignment, and bores may have twists or no clearance at the inside radius.
    Or less than flat mounting surfaces or end stop surfaces.

    Not difficult to make a fixture to measure both bores at once, in both radius and at end surfaces.
    High precision linear rod (guide), v blocks, 4 x 2 micron dtis.

    2.
    Seals.
    Non-contact zero-friction labyrinth seals are available cheap, about 40$.
    See Nilos rings.

    3.
    Fit the reworked spindle and the better bearings and the new seals into the machine.
    You now have the worlds best 14x40 generic import lathe.
    Congrats !
    Similar in basic runout to the discontinued Grizzly ultra-precision 1 -micron tir machine at 40.000$, then 30.000$.

    BUT, except...
    4.

    After running-in the bearings, grind and/or rigid lap the spindle surfaces to run true.
    This is the most critical part !

    Even crap bearings repeat pretty well.
    This is why the import lathes work ok, since the spindle runs pretty true, after the mounting surface is trued running in it´s own bearings.

    SKF, Timken, et al allude to this in their MT spindle bearing literature.

    ?? See what it takes ?

    It is not difficult as such.
    It is involved.

    And laborious, as a one-off artesanal industrial high-accuracy job.
    wow, thank you. a lot of info there...

    the parts I do not understand pertain to what you said about hand work and lapping with rigid laps / adjusting screws / truing the mounting surface.

    do you mean truing the spindle bearing mounting surfaces to each other? so in other words take the bare spindle out of the machine and true both bearing surfaces so both have zero run out in relation to each other?

    what would I be hand working with rigid laps? the bearing surfaces themselves?

    Judging by how the spindle turns I would say just new bearings and seals would make a big difference. the spindle does not seem out of alignment, just a lot of drag from seals and the crap bearings. the bearings do not sound like they are grinding, but you can hear the rollers on the races dragging to some degree. the machine does produce nice surface finishes for the most part.

    maybe its not worth messing with....but that super smooth spindle has me hankering...

  17. #12
    Join Date
    Jun 2008
    Location
    Roanoke, VA
    Posts
    672
    Post Thanks / Like
    Likes (Given)
    192
    Likes (Received)
    253

    Default

    Sometimes the construction of the gearbox makes a lot of resistance, a geared head lathe can usually be put between gears and will roll over easily. If there are drive belts from the spindle down to the gear train then you're dragging a bunch of belts over sheaves and that takes work.

    Rolling the chuck around indicating runout is the only time I use neutral on my lathes so as long as the drag didn't make it laborious to indicate work I'd leave it alone. There does stand a real chance you'll take it apart and not get it back together.

  18. #13
    Join Date
    May 2003
    Location
    Walla Walla Wine and Wild Turkey
    Posts
    4,683
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    370

    Default

    Quote Originally Posted by digger doug View Post
    Take your HF $9.99 angle grinder, and engage the spindle.

    Reach in and grind the spindle smoother for better engagement.
    HF now has an improved grinder for only $5 more it will run another hour.
    I cant remember one experienced machinist ever buying one of those lathes, or at least admitting it on a forum.
    The sad fact is an Atlas lathe is much better then that, better bearings.

    The 14" size imports are mostly a jacked up bench lathes, no where near what really an industrial grade machine like the 14" Webb, Cadillac, or Takasawa is. There was also Goodway, Victor and others. Those machines would run a good 5yrs with few problems.
    Grizzly has apparently zero quality control on this continent, you get whats shipped in from China, if its bad you ship it back and they send another.

    My observation over many years with the cheap machinery is, most often beginners do not have enough experience to know their machine is faulty, experience bad results, cant advance lose interest.....3 in 1 machines, mill drills, crappy lathes.

  19. #14
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    8,481
    Post Thanks / Like
    Likes (Given)
    2047
    Likes (Received)
    5895

    Default

    Quote Originally Posted by donie View Post
    I cant remember one experienced machinist ever buying one of those lathes, or at least admitting it on a forum.
    Well heck, I'd see a doctor about that short-term memory issue, as I mentioned I had one in #6. If 40+ years in the trade's not experienced enough, please tell me how much longer I need to go to qualify, and I'll see if my warranty's good for it.

  20. Likes Joe Rogers, TeachMePlease liked this post
  21. #15
    Join Date
    May 2017
    Country
    FINLAND
    Posts
    1,958
    Post Thanks / Like
    Likes (Given)
    535
    Likes (Received)
    884

    Default

    Quote Originally Posted by Milland View Post

    BTW, I also have a CN import 14 x 40, and it's not a bad machine for the money, except for an oil leak from the headstock past a seal on the power feed output shaft. I live with it for the moment, but at some point will cap it off when I convert to CNC operation.

    I'm mostly doing that so I can post a progress thread here to drive the other members batty.
    MACH3 please?

  22. Likes Milland liked this post
  23. #16
    Join Date
    May 2017
    Country
    FINLAND
    Posts
    1,958
    Post Thanks / Like
    Likes (Given)
    535
    Likes (Received)
    884

    Default

    Quote Originally Posted by Cleancut View Post
    Hey all,

    I have a 2010 model grizzly type 14x40 lathe. same quality, different name. actually fairly nice machine for the money.

    my question is in regards to how much force it takes for the spindle to turn ( in neutral).

    For instance, some machines spindles will glide very smooth with even a light touch - this machine will glide a little, but it definitely slows down, and has much more resistance then some machines.

    Can this be adjusted with the screw collars on the end of the spindle, or is it due to the lower quality bearings used in the imports? the spindle is very stout and has no runout.

    I have seen some imports with very smooth spindles, maybe I just got unlucky.

    Im running new AW46 oil in the gear box.

    thanks for any input.
    Some drag is perfectly normal or even desirable with preloaded bearings (angular contact or tapered roller) like these lathes typically have.
    Normal test procedure for some models is to give good spin for the chuck with your hand and if it rotates more than x rotations your bearings are actually too loose.
    Like others have said, unless the headstock/spindle heats up considerably(hot to touch) at maximum speed there is nothing to worry at the moment.

  24. #17
    Join Date
    Sep 2009
    Location
    barcelona, spain
    Posts
    2,436
    Post Thanks / Like
    Likes (Given)
    549
    Likes (Received)
    1454

    Default

    1.2.3.
    Yes.

    You would be removing less than 0.01 mm of material, and mostly on an inclined plane.

    4.
    Almost certainly no, big NO.

    Lathes are all about rigidity (+load capacity) under load.
    To a degree totally un-imaginable.
    And totally non-intuitive.

    Truing bearing surfaces is about adjusting the cylindricity to about 0.01-0.03 mm at a distance of 1 m.

    The spindle easily bends to allow a surprisingly big misalignment, and so does the headstock.

    Test:
    Put dti in spindle shaft inside hs, in the middle.
    Press on spindle by hand, firm (10 kgf).
    See ?
    The spindle bends several 0.01 mm, maybe 0.02 mm / 20 microns, with hand pressure.

    The bearings are rated for 4000 kgf force, each.


    Quote Originally Posted by Cleancut View Post
    wow, thank you. a lot of info there...

    the parts I do not understand pertain to what you said about hand work and lapping with rigid laps / adjusting screws / truing the mounting surface.

    1.
    do you mean truing the spindle bearing mounting surfaces to each other?

    2.
    so in other words take the bare spindle out of the machine and true both bearing surfaces so both have zero run out in relation to each other?

    3.
    what would I be hand working with rigid laps? the bearing surfaces themselves?

    4.
    Judging by how the spindle turns I would say just new bearings and seals would make a big difference. the spindle does not seem out of alignment, just a lot of drag from seals and the crap bearings. the bearings do not sound like they are grinding, but you can hear the rollers on the races dragging to some degree. the machine does produce nice surface finishes for the most part.

    maybe its not worth messing with....but that super smooth spindle has me hankering...

  25. Likes Cleancut liked this post
  26. #18
    Join Date
    Apr 2018
    Country
    CANADA
    State/Province
    British Columbia
    Posts
    65
    Post Thanks / Like
    Likes (Given)
    25
    Likes (Received)
    7

    Default

    Quote Originally Posted by donie View Post
    HF now has an improved grinder for only $5 more it will run another hour.
    I cant remember one experienced machinist ever buying one of those lathes, or at least admitting it on a forum.
    The sad fact is an Atlas lathe is much better then that, better bearings.

    The 14" size imports are mostly a jacked up bench lathes, no where near what really an industrial grade machine like the 14" Webb, Cadillac, or Takasawa is. There was also Goodway, Victor and others. Those machines would run a good 5yrs with few problems.
    Grizzly has apparently zero quality control on this continent, you get whats shipped in from China, if its bad you ship it back and they send another.

    My observation over many years with the cheap machinery is, most often beginners do not have enough experience to know their machine is faulty, experience bad results, cant advance lose interest.....3 in 1 machines, mill drills, crappy lathes.

    That is totally incorrect. These machines are far superior to any pot metal atlas - both in terms of speed and rigidness. I would also rather be on this 14x40 ten fold compared to the old south bend I had. It lacked power feeds (Both on Z and Y), was a bit flimsy, and finally lacked any real speed. I can take a heavy cut on this 14x40 (with carbide inserts) break a nice chip, and leave a mirror finish. whats the problem?

    Im with ya on the fact that china's QC sucks (most of the time), and the fact they are taking over the world.....but for the money these machines are pretty good.

  27. #19
    Join Date
    Apr 2018
    Country
    CANADA
    State/Province
    British Columbia
    Posts
    65
    Post Thanks / Like
    Likes (Given)
    25
    Likes (Received)
    7

    Default

    Quote Originally Posted by hanermo View Post
    1.2.3.
    Yes.

    You would be removing less than 0.01 mm of material, and mostly on an inclined plane.

    4.
    Almost certainly no, big NO.

    Lathes are all about rigidity (+load capacity) under load.
    To a degree totally un-imaginable.
    And totally non-intuitive.

    Truing bearing surfaces is about adjusting the cylindricity to about 0.01-0.03 mm at a distance of 1 m.

    The spindle easily bends to allow a surprisingly big misalignment, and so does the headstock.

    Test:
    Put dti in spindle shaft inside hs, in the middle.
    Press on spindle by hand, firm (10 kgf).
    See ?
    The spindle bends several 0.01 mm, maybe 0.02 mm / 20 microns, with hand pressure.

    The bearings are rated for 4000 kgf force, each.
    Thank you , would you be able to show me an example of which type of rigid laps you are referring to?


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
  •