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  • #16
    Originally posted by henryr View Post
    I’ve spent hours over the last three days looking for tapered roller bearings with tighter than normal tolerances and didn’t find any. Timken and SKF


    For new bearings I would not stray far from them.



    Thanks,
    henryr
    ACB. Figure it out. JR

    Ooops.. P.S.> They are called Angular Contact Bearings....

    Last edited by JRouche; 03-11-2021, 02:04 AM.

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    • #17
      In the UK, a recommended bearing supplier is "Simply Bearings".

      https://simplybearings.co.uk/shop/Be.../c3/index.html

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      • #18
        Originally posted by MattiJ View Post

        As an example older Weiler (highly regarded German lathe brand) was calling for precision spindle bearings. After digging some old references it turns out that the designation is same as ABEC-5 today.
        All SKF ball bearings have been manufactured to ABEC-5 runout for something like last 30 years so sourcing replacement was rather easy.
        ABC-LMNOP?

        The bearing nomenclature has been decimated with all the fabled imports.

        I think, I could go see but the simple bridgeports from way back called out class 5 then 7. Why? Dunno. Just what the book says. I didnt write it.

        Skateboarders with their class 9 lol JR

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        • #19
          so what size and what precision do you need?

          if your talking about timken then "standart" is N/2/P6. "0" is B/P4 with about 4µ total runout depending on size. do you need better?
          Last edited by dian; 03-12-2021, 05:52 AM.

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          • #20
            It hasn't been mentioned yet but precision class 5 and 7 bearings also require very specific shaft and housing tolerances for their operation. Without the specified shaft/housing fits a higher class bearing is a waste and may not last as long as a standard bearing. Shaft/housing fits play into obtaining the proper internal clearances and preloads. Also, to get extremely low runouts with precision bearings its standard practice to also grind the internal spindle taper using the precision bearings in place.

            All I am saying is that there are a lot more factors at play in a precision spindle than just the bearing precision.

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            • #21
              I built a spindle once using tapered roller wheel bearings. I had no problem with runout, easily less than a thou. Somebody mentioned .005 could be acceptable- now that is going back to the Flintstones. Considering how easily modern machining methods can be within a couple tenths, I would be appalled at that much runout, even for a Chinese bearing.

              I think you could be well advised to order in a small quantity of regular bearings, and test them. Chances are that less than one out of ten would be rejects due to runout. Correct me if I'm wrong- but I'm thinking that if you can machine something to say half a thou, that will cover virtually everything you'd be doing. If these are going into a 'precision' lathe- say a toolroom lathe- then perhaps that's another thing.

              Just my 02
              I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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              • #22
                If you were to take the rollers out and lap the face of the big ones, you could reduce the rolling element contribution to the bearings runout.

                measuring them would be difficult.

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                • #23
                  Did you try Ebay ? When people buy out suppliers, factories, shop , they sell the bearing stocks off. They may ask a fairly high price , or be quite reasonable. But at the end of the day, many will sell for whatever they can get for them..
                  Precision is a relative term.... the process to make bearings is all precision work. So when you offer tapered rollers, rather than bushings... it's easy to say precision bearings. They are generally easy to adjust , a big plus.
                  Last edited by 754; 03-13-2021, 03:16 PM.

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