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Lathe build underway: Part 1, the spindle

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  • #16
    This is the bearing configuration:




    I am nearly finished with the spindle and will put up some pictures of the completed part tonight some time. It is designed for easy preload adjustment. One thing I learned over the years is that if you are going to put an adjustment on a machine it better be easy to adjust. If it isn't it will be ignored until there is a real problem. If you can't make it easy to adjust you are better off to spend the extra money on tighter specs and hardpoint component location.


    The reason I used SS for the spindle is because it was what I had on hand the right size. CLE is about the same as steel although the conductivity is poor. That will make no difference.
    Free software for calculating bolt circles and similar: Click Here

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    • #17
      yep that's the one...... converge on OD, wide "pressure diamond". Textbook example.
      1601

      Keep eye on ball.
      Hashim Khan

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      • #18
        Looks awesome so far.
        I am surprised you did not make a larger chuck mount, and go with a 5C spindle.
        I know your SB uses 1 1/2-8 and that is why you stuck with it, but 5C is so sweet. You could make a threaded adapter for your SB to go from 1 1/2-8 to 2 1/4-8. or whatever it is that SB also uses. Then you could still switch chucks. Perhaps 5C is not your thing, I get that. But you also want 16" of swing? with a small 1 1/2" chuck mount? I just wanted to spark your ideas before you get to far into it. FWIW, an A-type spindle nose is easier to make than a camlock, and even more rigid. I never minded the bolts. Just thinking out loud. Sweet bearings, by the way.
        --Doozer
        DZER

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        • #19
          Looks Good

          What is the SB Part Number for the Adjustable Locking Unit on Belt Adjustment?

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          • #20
            This is the finished spindle except for four bolt holes for the drive pulley. I'm cutting it short tonight because it's clear sky for the first time in weeks and I want to take some pics with my new drive gears.


            There is a gap between the chuck back and the register. I need to skim a couple of tenths off as it is just a bit tight winding on.



            This is the preload adjuster. The rear bearing is a sliding fit , just barely. The threaded part is a press fit on the spindle but I will pin it also to make sure it doesn't move.



            This is the drive pulley that I found at the dump. It should do nicely. It needs four threaded holes for bolts and will also get a spindle bore extension with a flange that clamps the drive pulley to the spindle.

            Free software for calculating bolt circles and similar: Click Here

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            • #21
              Originally posted by Evan
              This is the bearing configuration:



              No split ring configuration so it's a preset. the preload adjuster you are building isn't a preload adjuster at all but just an end float adjuster.

              Putting load on that adjuster will only put pressure on one set of bearings and reduce it from the other.

              To use this double angular contact design correctly you need either a split race double angular contact bearing or two separate back to back bearings with the adjustment nut directly behind the bearings.

              The way you have it you might as well just use one bearing.
              Those double bearings is designed mainly for wheel bearings on cars that need maximum axial capacity, which as you posted in your first post is 8 tons, nearly equal to the radial load capacity of 10 tons.

              Ideal for cornering loads but try any wheel bearing after a few 1,000 miles and it always has a little bit of shake, no problem on a car but image the surface finish if that were a lathe.

              .
              .

              Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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              • #22
                I have never seen a car with a bearing like this John. The configuration of this bearing is exactly the same as a back to back arrangement of a duplex pair of 7000 series angular contact bearings. That is a standard machine tool spindle configuration.

                Ideal for cornering loads but try any wheel bearing after a few 1,000 miles and it always has a little bit of shake, no problem on a car but image the surface finish if that were a lathe.
                Since I have no intention of doing any heavy cornering with this bearing on or off road I don't expect it to develop any looseness or shake. If for some unimaginable reason it does the "end float adjuster" will take up any slack and apply a preset bias to the bearing in the direction required when using it as a spindle bearing. I do believe that is known as "preload". My South bend, which has plane bearings and a single separate axial load only thrust bearing has an end float adjuster. While it looks the same it doesn't quite do the same thing.
                Free software for calculating bolt circles and similar: Click Here

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                • #23
                  Originally posted by Evan
                  I have never seen a car with a bearing like this John. The configuration of this bearing is exactly the same as a back to back arrangement of a duplex pair of 7000 series angular contact bearings. That is a standard machine tool spindle configuration.
                  No it is NOT.
                  Machine tool spindle configuration uses either two separate bearing or a split double so that both bearings can be adjusted load face to load face.
                  Often like the Bridgeport they use ground inner and out spacers to achieve the right preload.

                  There is no way in this bearing design to keep a preload on those two races other then what the manufacturer has deemed acceptable given the classification of the bearing.


                  Do a Google on double row angular contact wheel bearings.
                  or see here;

                  http://www.ourbearings.com/wheel_bearings.htm

                  If for some unimaginable reason it does the "end float adjuster" will take up any slack and apply a preset bias to the bearing in the direction required when using it as a spindle bearing. I do believe that is known as "preload".

                  That is true but it will only apply it to one side, as it applies it to one side, the one next to the chuck it will reduce it from the other side so in effect you are running on one bearing.
                  It is not an unimaginable reason it's called wear.
                  .

                  Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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                  • #24
                    No it is NOT.
                    Machine tool spindle configuration uses either two separate bearing or a split double so that both bearings can be adjusted load face to load face.
                    Not always.

                    Twin Spindle - Twin Turret

                    Model: 20A/30N/40N Series

                    FANUC 0i Mate Controller
                    High rigidity and heavy cutting
                    Live turret with C axis (including Mechanic & Control system.
                    6 driving tools onthe live turret offering milling, tapping and drilling operations
                    25-4000 rpm for the live turret
                    Double row high precision roller bearing and angular contact thrust double row bearings equiped high precision spindle
                    Programmable tailstock

                    [quote]


                    http://www.nachiengineering.com/pdf/B-MT.pdf

                    That is true but it will only apply it to one side, as it applies it to one side, the one next to the chuck it will reduce it from the other side so in effect you are running on one bearing.
                    It is not an unimaginable reason it's called wear.
                    I wonder how long that will take? I also wonder how much external preload it would take to reduce the internal preload to zero on a bearing rated for 10 tons.
                    Free software for calculating bolt circles and similar: Click Here

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                    • #25
                      [quote=Evan]Not always.




                      Thank you for than link Even you have answered my post.

                      Look carefully at the INNER ring, it's a 3 part ring, 2 bearings and a central spacer that sets the preload.

                      The outer maybe a one piece outer but the inner like most preloadable double angular contacts in in multiple pieces. That setup would have had the adjustment directly behind the bearing, NOT on the other end.

                      Here's the headstock of a CVA lathe which is a copy of the 10EE



                      Note the two bearings back to back with spacers 18 and 19 in-between and the locknut and lock 13-14 that pushes the thrust #16 onto the inner bearing.


                      I do know what I am talking about about on spindle bearings believe me, I don't suppose you came across many 50mm bore by 110mm OD 5310's in photocopier's did you ?

                      .
                      .

                      Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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                      • #26
                        I do know what I am talking about about on spindle bearings believe me, I don't suppose you came across many 50mm bore by 110mm OD 5310's in photocopier's did you ?
                        Not very often. Xerox didn't sell a lot of the very big machines. They cost near half a million dollars and require a 50 amp service for the drive motor and a 20 amp service for the rest.

                        From NSK
                        Double-row angular contact ball bearings are basically two single-row angular contact ball bearings mounted back-to-back except that they have only one inner ring and one outer ring, each having raceways. They can take axial loads in either direction.

                        http://www.tec.nsk.com/Handbook.asp?...arContact.html
                        This is the configuration I am using, as recommended by NSK.



                        I do know what I am talking about about on spindle bearings believe me,
                        I am beginning to wonder.
                        Last edited by Evan; 01-02-2009, 09:51 AM.
                        Free software for calculating bolt circles and similar: Click Here

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                        • #27
                          Originally posted by John Stevenson
                          It is not an unimaginable reason it's called wear.
                          Ball bearings DO NOT WEAR (if ball cages stay lubricated).

                          A ball bearing that wears is contaminated with some crap that acts as a lapping compound.

                          The failure mode for a ball bearing is fatigue cracking of the surface, with spalling off of pieces.

                          It takes a while, and is a function of both the total cycles (shaft turns) and the loading. More loading, earlier fatigue failure.

                          I do however, agree that the bearing in question may or may not be internally preloaded. if it IS internally preloaded, as New Departure did for their double row bearings, then your concerns are not applicable.

                          if it is NOT internally preloaded, then there is "clearance", only one row will be loaded, and an external preload will be required, as I mentioned referencing the Logan bearings, OEM 1942 parts vs new replacements from Logan.

                          The split is not the only way to preload. A one-piece bearing can be preloaded by selecting the balls in both races so as to have the proper interference to develop the preload, and by specifying the fit in the pocket or on the shaft. It's a bunch harder, I'd suspect, and would require the bearing to be loaded with fewer than the maximum number of balls, or you'd be hard--pressed to get all the balls in.
                          1601

                          Keep eye on ball.
                          Hashim Khan

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                          • #28
                            Evan, I was going to stay out of this but................... John does know what he is talking about. So do I. I spent a good portion of my working life rebuilding precision machining spindles and doing adjustments/diagnosing problems on them in service. What I was going to suggest if you want to keep the costs down on this project is to use two 72XX series non-precision bearings in a DB arrangement on both ends of the lathe spindle. The rear has to be able to float axially in the bore to allow for heat expansion while the front set has to be captured in its bore by its retainer (.005" is fine). The front set can also have a set of inner and outer spacer to adjust preload (a really good idea it to make the spacers equal to the width of two bearings so the set of two can be turned into a quad set). The bearings should not be pressed into either bore but have either a slight slip fit (.0005" ) with front set being maybe size on size. The only advantage to the double row sealed bearing you showed is its seal.
                            Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.

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                            • #29
                              The only advantage to the double row sealed bearing you showed is its seal.
                              Not so. It's free instead of costing $200. That's a big advantage. In my original post I said I was building this with what I have on hand. This is what I have on hand and there is no reason it won't work. I am not designing a commercial product that must be produced to compete in the market. I am designing something that will allow me to turn larger diameter work pieces than my SB9. It should do that very well.
                              Free software for calculating bolt circles and similar: Click Here

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                              • #30
                                Originally posted by John Stevenson
                                No it is NOT.
                                Machine tool spindle configuration uses either two separate bearing or a split double so that both bearings can be adjusted load face to load face.
                                Often like the Bridgeport they use ground inner and out spacers to achieve the right preload.

                                There is no way in this bearing design to keep a preload on those two races other then what the manufacturer has deemed acceptable given the classification of the bearing.
                                John's right -- you can't preload a double row angular contact bearing, because the two bearings are fused together. That's why they're not used in machine spindles. Spindle bearings are individual duplex or triplex pairs, and the preload spacer wedges the inner or outer races of the two bearings together.

                                Double-row angular contact bearings are usually used in non-precision applications where there are dual axial and radial forces -- compressors, pumps, screw drives, ... If you got the bearing from a photocopier, it's probably the latter.

                                If you're looking for a large spindle bearing on a budget, one suggestion would be to use a single precision tapered roller bearing. Then you can use your existing preload threads to preload the cup into the cone.
                                Last edited by lazlo; 01-02-2009, 11:18 AM.
                                "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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