Spindle Taper Roller Bearings

  1. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    Noticed bearings feel a bit rough, some play and excessive friction, so going to swap them. Ive been told the size is 32007 *2. Anything I should know? SKF/Timkin are not expensive in this size.

    Second question how did I ruin them? The lathe was not set up well for parting, so I often hacksaw'ed static parts held in the chuck, caused brinnelling? Or by tapping morse taper tools out?
    Or, its just a Chinese lathe with Chinese bearings, 4 years is not bad, for what I have done.
     
  2. Pete.

    Pete. Member

    Messages:
    8,674
    Location:
    Kent, UK
    Chinese lathe with Chinese bearings. Spindle bearings are not easy to damage from abuse, they put up with interrupted cuts, chatter, knurling and serious harmonics when you get to the limit of your rigidity. Tapping out the odd taper and using a hacksaw is a non-issue.

    7007 is the super precision size for those diameters but they are only 14mm wide so would need spacers.
     
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  3. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    I know nothing about precision bearings, but I thought taper rollers were better than AC type? Interested to know more. Do super precision TR's exist?
    Thanks
     
  4. Pete.

    Pete. Member

    Messages:
    8,674
    Location:
    Kent, UK
    No idea about that mate.

    Angular contacts are fitted to the top end manual lathes so I imagine they are about as good as you can reasonably get. Whether the machining (or stability of the casting) on the Chinese lathe's headstock is good enough to warrant it is another matter. I'd just fit the Timken rollers and see where you're at. If the rear inner race is tight on the spindle, do something about it before building the spindle up or you might find it difficult to adjust the pre-load.
     
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  5. ronan

    ronan Forum Supporter

    Messages:
    9,363
    dublin
    Just fit a quality version of what was fitted originally, Skf or rhp or a good brand like that. The Chinese bearings are not very good, some i have seen are not even hardened.
     
  6. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    1,797
    essex england
    If you’re mad rhp gold
    Any good bearing is a up grade
     
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  7. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    Thanks Pete, please could you explain the rear inner race, does it need to be moveable for the front bearing to become preloaded? Wouod it not be pressed to the correct position as the spindle nut is tightened?

    I phoned SimplyBearings to try get an understanding of the bearing codes and order. Useless. I had to explain what a lathe is. Q apparently means "quiet" and J2Q is something about having a steel cage, but so are all the others. I already knew X means same dimensions but higher rating.
    Chose these SKF only for quicker postage, www.ebay.co.uk/itm/SKF-32007X-Q-Metric-Taper-Bearing/173925072951
     
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  8. Pete.

    Pete. Member

    Messages:
    8,674
    Location:
    Kent, UK
    If there's too much sticktion the bearing won't pull up smoothly it'll make little jumps as it creaks along the spindle OD. You can't gauge the pre-load and when you finally get it pulled up you'll probably over-shoot and then find the only way to back off is to start beating the end of the spindle.

    It might not be an issue with your machine but if it is it's better to spot it early and take measures.
     
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  9. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    Well I can measure it... for 35mm, should be around 34.95mm?
    To precisely remove a blond one without a second machine might be a challenge.
     
  10. Pete.

    Pete. Member

    Messages:
    8,674
    Location:
    Kent, UK
    Just fit the front bearing and if it's tight you know you have to ease the fit of the second. You could make a lap and have it handy.
     
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  11. Laurie Tedcastle Member

    Messages:
    30
    Location:
    NW Northants (UK)
    @Kram

    In post 3, you asked if super precision taper roller bearings exist. Short
    answer - yes.

    In the mid 1970s, I had a visit round Timken's Daventry plant which
    manufactured all the low volume and special bearings (high volume was done
    at Duston - Northampton). At that time, they could not grind the components,
    to the required tolerances, for super precision bearings (eg machine tool
    spindle bearings). Their solution, as in many other industries, was selective
    assembly. The races and rollers were measured, put into stock separately per
    the measurements and when the required combinations were available, withdrawn
    to build the bearings. Large storage area required and some parts might spend
    a long time there. All very costly. At the time, lead times for Herbert lathe
    spindle bearings were typically up to 18 months.

    I don't know how modern manufacturing techniques will have changed/improved
    this, but I'm sure someone will soon be along to tell us. However the British
    company HB Bearings (hb-bearings.com) has told me they can even manufacture
    1 off. No connection with the company, just talked to them at "Race Retro".
    They will reverse engineer difficult to source bearings, if they don't already
    have the necessary details. It appears they now own GAMET bearings.

    Laurie
     
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  12. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    Has a quick look on youtube and found this,
    Shouldnt suprise me, rest of lathe was coated in this grinding paste but I did not want to touch the spindle.



    2m55s - I cant get time links to work on embed video.
     
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  13. Pete.

    Pete. Member

    Messages:
    8,674
    Location:
    Kent, UK
    That video makes me feel seasick. Does he live in a quake zone?
     
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  14. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    1,797
    essex england
    When dealing with sub micron selective assembly is the only option.
    That also includes orientation of concentricity errors in the races.
    Even the best bearings look bad under a talyrond scrutiny or equivalent.
    Laurie tedcastle, thanks ive recorded hb bearings as I get involved with obsolete stuff occasionally
     
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  15. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    Not easy to watch!

    [​IMG]

    Took bearing cap off mine to inspect and its no different. Thick dirty dry grease with plenty of grit. Im impressed with the chinese bearings they must be decently hard to withstand that since 2015. Gave a squirt of oil on the rear and it is much smoother. Measured 0.03mm deflection, pushing and pulling on the spindle.
     
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  16. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    I am quite sure the rear is a tight press fit. The preload is not adjustable and wouldnt move with the nuts off. Any good way to adjust the fit for new bearing? Sanding a bit off by hand is not a good idea.

    Had a couple of ideas to improve it. First, there are no proper seals, so oil lubrication is out, and swarf can get in. I think it can be improved a lot:
    1) Replace the outer bearing caps with new spacer and oil seals.
    2) Front of headstock (facing user) is open, with 1mm sheet. Add thick internal bolted cover to brace it.
    3) Internal spacer tube between the bearings to support casting.
    4) Oil seals inside spacer tube and seal spacer ends by compression to headstock. This means bearings can be oil flooded rather than grease. Internal faces would need to be filed flat.

    Spacer tube also needs a slot for the speed wheel and sensor.
     
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  17. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    [​IMG]

    It looks like the headstock has bearing seats pressed in, which atleast gives a flat surface for the spacer tube.

    The lathe can do some decent cuts but as soon as the loading is radial - grooving or parting, it gets an extreme amount of chatter. I think this is caused by the open headstock design.

    Yes, Warco paint after assembly .
     
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  18. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    10,016
    Location:
    Bedfordshire England
    Have you checked your cross and compound.
    Play there would cause chatter too?
     
  19. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    Yes I always lock saddle for parting or grooving. Compound is locked most of the time. Cross is adjusted doesnt have much play, but I will check it again.
     
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  20. Kram

    Kram Member

    Messages:
    692
    Location:
    Sussex
    If I get the spindle out to measure for the spacer tube - will the rear/both bearings be too damaged to temporarily refit, in which case Ill order some cheap ones. I will need to turn spacers to length after, and I dont want to fit the good ones before I have that done.

    Im going to stick DTI and 240fps camera on to see if the front face of headstock is moving.
     
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