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R & R Spindle Bearings and Cleaning

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  • R & R Spindle Bearings and Cleaning

    I spent part of the day tearing down this spindle as it was getting noisy due to dry bearings. My cleaning method is as follows........ After removing the spindle from the cartridge and taking careful notes as to what I find inside, bearing orientation, shims, spring washers etc. etc. I soak the bearings in parts washer fluid to remove the old caked up grease. This make take several hours of soaking and blowing out the old stuff. When they look about as clean as they can get I then put them in the vibrator soaking in laquer thinner and let them vibrate for about 15 min. I do this three of four times or untill the thinner remains clear. In the first picture you can see how the thinner is yellow as it removes the grease film that the solvent wouldn't touch and also sifts out some small particles. When I'm satisfied that they are clean I then procede to the final cleaning step.
    Soaking and vibrating in alcohol. This step removes any film left by the thinner and the bearing are actually squeeky clean. then I pack them with grease and they are ready to install.


  • #2
    I should have posted these pictures first but..................

    Here is a picture of the quill after I pulled it apart.
    I also indicate the spindle to insure proper bearing orientation.



    • #3
      Are the bearings sealed on both sides?
      It's only ink and paper


      • #4
        Pretty much the bearings are shot. Once you remove them from a spindle its all over.


        • #5
          No the bearings are not sealed, the end caps of the spindle are the dust shields, and why do you say once you remove the bearings they are shot????? thats not true. I think some people have this misconception about precision spindle bearings that if you look at them the wrong way you ruin them. I've done several of these with excellent results.



          • #6
            Its pretty well known once you take them out they will never be the same again. I have tried it, much as you have, and it has never worked in the long run. Once a set of bearings is installed and ran they take a set a wear in during run in and operation. Unless you are very, very careful and get them back in place exactly how they were in relation to the spindle housing and the spindle they will not run.

            Check on ebay, you can often find NOS bearing sets for pretty cheap, sometime under $100 a pair.


            • #7
              I've re-installed spindle bearings. Many times a spindle has to be disassembled for non-bearing problems (leaky seals, gears, clutches, or shifters, access, whatever.) Some spindle bearings cost a fortune ($30K a pair to take the most expensive in my experience.) It's criminal waste to discard them without reason.

              Naturally, they have to be pulled with care and sometimes this requires a specially made puller. The outer race generally has a small clearance so it will come right out with a little pursasion and maybe heat. If you get purchase on the inner race and pull without loading the outer race the bearing for all practical purposes is still in used but unabused condition. Taper roller bearings have comparable requirements but its often very tricky to extract the outer races without damage inless there are extraction reliefs in the bore shoulder; fortunately if there is no problem there's no reason to.

              Then there is cleanliness, grease (if used), race orientation, reassembly order, etc. Touch all the bases and use good technique and spindle bearings can go in and out any number of times. There is surgical risk to consider but if everyone is on his game, there should be no problem.

              BTW, what do you call a "vibrator?" The gizmo in the picture looks like an ultrasonic cleaner, a deadly enemy of assembled precision bearings because of the zillions of high energy impacts between balls and races.
              Last edited by Forrest Addy; 05-15-2011, 04:57 AM.


              • #8
                Unless the bearings are worth a fortune and would replace with new. Looks like a lot of work taking the spindle apart just to put a old set of bearings in that were running noisey/dry. That sound is the sound of the bearings being worn.


                • #9
                  Here's a thought....

                  A guy could always try cleaning and re-lubing bearings first. If it works, it could save hundreds of dollars. If it doesn't, then you could always pay for new ones after determining it needs to be done.

                  Of course if you've got money to burn, then by all means throw as much money as you want to at it. Otherwise, all you've lost is a little time. Unless you're in a production machine shop where lost machine time offsets the cost of precision bearings, then a second round of removing and installing new bearings is worth the learning experience of doing it the first time.

                  Just my opinion. But I'm right, so...


                  • #10
                    People talk about bearings bein "worng." End of life for a rolling elemenrt bearing is failure of the rolling path in the races and/or the rolling elements.

                    R/E bearings do not suffer failure from loss of material due to mechanical wear. A preloaded bearing will not get "sloppy". The preload may relax somewhat but if the related parts are still in their orginal adjustments the bearing's axis and smoothness of operation will last for some time.

                    I was going to write one of my famous "things" but while looking up a tedious point I found this which says it better and with pictures:

                    Last edited by Forrest Addy; 05-15-2011, 06:49 PM.


                    • #11
                      JoeLee, that black ring between the inner and outer races looks like a black rubber seal to me. If the bearing has no seals I should see retainers and balls showing in the photo. It appears to me they have a seal on at least one side.

                      It is almost impossible to get all the grease and any dirt out of a bearing with a seal on one side. I have cleaned, greased and reused bearings before and sometimes it worked and sometimes it didn't. If they were common run of the mill bearings I would clean and reuse them but bearings for a mill spindle or tool grinder would probably get replaced. Unless money was tight or I couldn't find them.

                      Many times when the grease dries out in the bearing the balls and races get damage from lack of lube so cleaning and re-greasing them is not much help. Especially in high speed bearings.
                      It's only ink and paper


                      • #12
                        I have reused bearings of all kinds. The USAF reuses wheel bearings on high speed jets. After a good cleaning and inspection lube and they are ready for reuse. One sure way to trash a bearing is to spin a dry bearing with air..

                        Also they should never be packed completely full of grease. About 3/4 is enough.


                        • #13
                          On precsion bearings, the bearing manf. will give you the exact CC of grease allowed for a particular IIRC, my surface grinderBarden's are about 40% fill.

                          Following on from Forrest's post - to look between the balls in the races, I use an Otoscope (one of the thingys the doctor looks inside your ears etc).

                          Now they are very cheap (non-medical) and use LED light sources. Mine was about $14. Very useful for a host of machining inpsections, including finding metal slivers in fingers.

                          Mine looks something like this :
                          Last edited by lakeside53; 05-15-2011, 12:11 PM.


                          • #14
                            Carld, the black ring your reffering to is actually brown until it's coated with grease, it's the phenolic bearing cage or seperator or what ever you whant to call it, it does look as if it were a seal in the picture but there is a slight space where when the bearing is cleaned you can see the balls. A visual inspection of the race does tell a lot, if a matt finish is detected where the ball rolls then I would say that the bearing has some wear and should be replaced. If all is bright and mirror like with no detectable tracking and all else checks out then I would call it reusable. Back when I did my first spindle some 15 years ago I was unsure about R & R,ing such precision bearings. I called Fafnir and spoke to one of the engineers about doing this in my grinder spindle and he said as long as your careful taking the bearing out there shouldn't be a problem. He told me as long as I don't beat them off with a hammer or try to press / pull them off with a 1000 lbs. of force I would be OK. For a second opinion I called KO Lee and spoke to one of thier engineers, he said hell we remove new bearings all the time if were not satisfied with the run out. We pull them off and slightly reposition them on the shaft and check the runout again, and do this until satisfied. Altough the spindle is checked for high point and properly aligned to the marking on the bearing doesn't always mean the results will be perfect.
                            If you can hold tolerance when grinding and the finish looks good then what else could you ask for??
                            When you remove these bearing just make note of the markings on the races in relation to the housing and spindle and don't switch left and right bearings around either. Worse case is you buy new bearings.



                            • #15
                              The difference would be whether you can remove each race purely by pressure on THAT race.........alone.

                              If you can, then what is wrong?

                              If you cannot, then you will be, for instance, removing an inner race by pulling on the outer race, which will risk brinnelling the race by denting it. That's if the pressure is more than the allowable load for the bearing (static). Even if not, it may remove some life by adding a very heavy "cycle" to the fatigue stress.

                              The mere act of removing a bearing, properly, should not affect it.

                              Keep eye on ball.
                              Hashim Khan