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Removing tapered spindle roller bearings

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  • Removing tapered spindle roller bearings

    I'm replacing the Timken roller bearings on my Rockwell 11 lathe as it's never been right since I oversped it after fitting a vfd to it.

    I noted with interest Forrest's advice regarding heating them in a toaster over in order to get them on, but what's the recommended procedure for getting them off?

  • #2
    In general, some sort of puller that can get a grip behind the bearing is needed to remove this type of bearing without damaging it or the shaft. There are a lot of very special ones made that will clamp onto the rollers or the lip of the race and will work where there doesn't seem to be any way to get a grip for a puller.

    A common method is to remove the rollers and grind the race to weaken it enough to split it. Bearing races are quite brittle and break easily when this is done. A small cutoff wheel in a Dremel tool gives good control. Unless it is in a sealing area nicking the shaft actually does no harm but is to be avoided if possible.

    A cutting torch will make quick work of removing it without damaging the shaft if one has reasonable skill with it. It is also possible to heat the bearing and use a chisel to stretch it but that may be more likely to overheat the shaft.
    Don Young

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    • #3
      There are "Bearing Separators" on the market in different sizes that work.

      Any of the major tool guys carry them.

      Just not sure if your'e situation will allow them to be usefull though.

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      • #4
        As mentioned blind bearing pullers, bearing splitter type pullers, and presses all work depending what the situation calls for.

        Another option I use quite often that is quick, is to remove the roller cage and rollers, then one or two mig or stick weld beads on the inner race, and the inner race literally falls off.

        This technique also works for removing outside races that are hard to get a hold of when they are in a blind hole. I used to weld a round steel disk inside the race so that I could use a puller on the pre-drilled hole in the disk, but the race usually fell out before I could mount the puller.
        Home, down in the valley behind the Red Angus
        Bad Decisions Make Good Stories

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        • #5
          Any way not to destroy it in the process?

          Aw, geez. I found a cone on ebay and already pushed it on. Now I've found a cone and a cup and want to add them to the mix.

          If I leave it in the freezer overnight and hit it with a heat gun, do you suppose that would allow me to pull it off?

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          • #6
            You're talking about spindle work and the spindle is at once the most delicate and also the ruggedest component on the lathe. It's delicate in that it's easy t really screw something up pulling a bearing and it's rugged because it will take the severest shock in accidental operation without harm.

            Without knowing the details of how your headstock is constructed I'd hesitate to make any recommendation. Rapid temperature changes you would use removing an axle bearing are out with a spindle. Abrasive slitting the inner race is perilous because it's so easy to slit the spindle too. Also the part of the bearing next to the shoulder is inaccessible to the slitting wheel. You might break the race at that point by wedging it with a sacrificial screwdriver in it but as I said this method is perilous.

            No amount of feezing or slow heating will aid bearing removal because most steels expand at close to the same rate.

            Your best bet is to use a bearing separator Here's how to use a separator as applied to an axle flange. http://www.youtube.com/watch?v=FA1x7IaclTM

            A spindle bearing is pretty much the same as the video except the pull is away from the spindle flange towards the index gear end. You will need long studs and a way to protect the end of the spindle from the puller screw. Do you know any experienced mechanics? A little mentoring is probably a shrewd idea if you've never pulled bearings. Maybe take the spindle to his shop for some show and tell.

            Do not damage or bruise the spindle. Come back to this thread to report progress.

            Take pictures as you go. Take notes and make drawings too if they will help you in reassembly.

            Don't forget to replace the spindle seal and install all the retainers, flingers, seal housings etc ahead of the replacement bearing in assembly order before you shrink the bearing on. BTW, if you replace bearing there may be spacers and shims to fit so the axial position/preload, etc work out. Work clean.

            There's much DYI material to Google. Use "replace lathe spindle bearing" as a search object. Also most major bearing manufacturerers have bandy how tos for working with high precision bearings.
            Last edited by Forrest Addy; 08-14-2011, 12:56 AM.

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            • #7
              Many Spindles with tapered bearings allow you to press off the cones, using a hydraulic press.
              Rich

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              • #8
                Some stuff seems to have heavy press or shrink fits for the cone.....

                While it is not a "spindle", the crank shaft of an Atlas shaper has one that was supplied as a unit when a spare was ordered. There is no part listed for the shaft with no cone.

                I needed to replace mine, and it was NOT coming off, with no place to insert a drive rod to press or drive it off from behind. There is a large flange in the way.

                I cut the cage, and then cut the race with a Dremel and a narrow slitter disk. When I got it down fairly thin, there was a sharp "crack" noise, and the race broke through from forces due to the heavy fit.

                I don't think there is ANY way to 'pull" that cone off.
                1601

                Keep eye on ball.
                Hashim Khan

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                • #9
                  Progress report

                  There are a couple sheet metal grease washers between a shoulder on the spindle and the first cone, they're stiff enough that I was able to press it off w/threaded rod and pieces of pvc pipe.

                  I started using a heat gun for shrinking the bearing on. That works great. I screwed up on one and got it half seated before realizing it. Using a small nozzle on the gun, I was able to heat up the inner race enough to be able to lift it off by hand and correct my error.

                  I've now replaced three of four bearing components and the results are heartening: very little movement on a DTI whereas before it would wander back and forth over more than a thou. If a 382 cup comes up on ebay, I imagine I'll go through the process of changing the bearings again.

                  What kind of damage might it do to press off a cone by pushing on its cup? I heard the term 'brinnelling' here, I think.

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                  • #10
                    Originally posted by rohamm
                    What kind of damage might it do to press off a cone by pushing on its cup? I heard the term 'brinnelling' here, I think.
                    I could be wrong but I believe brinnelling is caused by trying to tap a bearing on or off, which is verboten.

                    Chris

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                    • #11
                      "What kind of damage might it do to press off a cone by pushing on its cup? I heard the term 'brinnelling' here, I think."

                      you heard right. It will ruin the bearing. Even if the damage is not visible, it's there.

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                      • #12
                        generally 'brinneling' is regarded as the plastic deformation to a surface by a hardened roller or ball, can be found in mismatched bearing races and cages as a track or linear indentation around its internal or external circumferance or longitudonaly along a linear bearing, i beleive it came to be described either just before the conception of the brinell hardness test [in which case it may have been his motivation to invent the test, or definately just after!, the brinnel test being the amount a hardened ball can be pressed into a surface] usually bearings have matched hardness values so to reduce the effect but running fast/heavy load lubricant fail [and loads of other things] cause the effect;wear welding and so on, all bad!
                        http://www.miics.net/2006/download/22doll.pdf
                        http://www.machinerylubrication.com/Glossary

                        the main bearings will as pointed out smash quite easily, if you are going to belt one the thin cutting wheel option is best, cover with a rag and give a sharp crack with a knockometer, save the rollers handy for measuring! you can hire a timken induction heater off your bearing supplier to properly install new ones, you can stick them in the oven or on a hot plate but care is required not to damage, i did leave one overcook recently,oops+ass chew as it was a 300mm bore and the induction heater was as usual broke!
                        regards
                        mark

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                        • #13
                          When breaking a race off, deferably cover it with something, shards fly and cuts from them bleed forever. Heating a new race in oil to expand it is quite effective.

                          Regards Ian.
                          You might not like what I say,but that doesn't mean I'm wrong.

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