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Lathe Spindle Bearing Adjustment Question

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  • Lathe Spindle Bearing Adjustment Question

    I have got my Colt headstock partially apart. :-)

    They look like taper roller bearings. They are marked BOWER Japan
    I quick search of the web seems to show they are very inexpensive.
    Is Bower a OK brand? I don't think I am going to change them yet. Unless I find a problem with them.
    Should they be greased or Oiled?
    What would be the suggested technique to adjust or set the pre load on them?
    How much of a sin is using this type of bearing in a lathe head stock?

  • #2
    Whats the number on the bearing? 60205? If so, thats a cup and cone bearing not unlike a wheel bearing. You find them in drill press quills among other places.


    • #3
      Its 30205.


      • #4
        If you google "30205 bearing" you'll get lots of hits. It is a tapered roller bearing, and I think any quality 30205 will be the same, but I'm sure a real expert will chime in. I cannot recall right now if these are rated like ball bearings, ie with an ABEC rating. If so, the higher the number the better.

        What kind of bearings are at the other end of the spindle, and why are yu going to replace this one?



        • #5
          I assume a similar one is on the other end.
          I am only going to replace if needed.
          The bigger question is how much preload is required.
          The Headstock/ spindle currently has movement in and cuts a taper.
          I need to adjust the bearings then go on to finding other issues.
          Thanks for feedback. It does look like a real common bearing.


          • #6
            Does that mean you can grab the spindle and move it in and out of the headstock a detectable amount?

            Was the spindle noisy before?



            • #7
              Snug it up tight and back of the net about 1/8 turn . Run lathe and see what happens may need more are less . Just play with it . Feel for heat in head stock around bearing area . If it gets hot loosen up some . Those bearings will last the life of the machine . Longer than you will live . No big deal. These little machines are not high precision . But will do all you are ever capable of.
              Every Mans Work Is A Portrait of Him Self


              • #8
                Dave, I don't think Your oil or grease question has been answered yet.
                Yes the bearings need oil. On My import machine with tapered bearings there is oil holes in the top of the headstock casting and a sight glass in the front that shows when the oil level is sufficient. Your machine will probably be slightly different.

                After further review of Your picture, it appears that there is grease in there now.
                Last edited by doctor demo; 12-11-2010, 09:00 PM.


                • #9
                  Thanks for the procedure. I will give that a try. I have not been able to snug it up yet. I will have to try again. I think I will have to make a adapter as the adjustable face pin spanner is rather small and hard to tighten down.
                  Its a little harder than setting a wheel bearing since it does not have the same flywheel. If I recall on a wheel bearing you would snug up until it started to drag then find the next notch in castellated nut.

                  The issue is the 0.010" taper over 1 inch I get when I turn. No noise.
                  If I chuck a bar in chuck I can get +_ 0.005" deflection without much effort on a DI.
                  Yes it has grease in in now. It has grease fittings. On a real Myford you need to oil the grease fittings.
                  I think I will leave the grease in for now until I know otherwise. I checked a bearing spec says its rate to 7K oil 5K grease or something like that. Should be fine for this. The bearings seem to be used in trailers so grease should be good.

                  Thanks you all for the good stuff.


                  • #10
                    There should be no detectable play in the spindle with that type of bearing. .005 is way way too much. You do need to adjust it, basically once you are able to alter that play you can at first tighten it to eliminate the measurable play, then run it for a few minutes. There should be some heat generated, but the headstock should never get more than warm. You should never find that, even after extended running, you can't keep your hand on the headstock. If it even approaches that temperature, it's too tight.

                    The taper you are speaking of- seems to me that the headstock is out of alignment. Play in the spindle might give a poor finish to the work, chattering, etc, but I see no reason why it would cause a taper of that magnitude. But don't try to correct that before getting the spindle pre-load set properly. You should be able to take a skim cut and a spring pass, then the cutting tool should quit cutting. Then you should be able to adjust for another half thou and the tool should take off that much. With the spindle play as it is now I would expect that every spring pass you take, you'll be taking off material, and it won't be coming off evenly. As the spindle bounces, the workpiece will randomly move towards the cutter- pretty hard to get precision work done this way.
                    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


                    • #11
                      Back her off

                      Originally posted by lane
                      Snug it up tight and back of the net about 1/8 turn . Run lathe and see what happens may need more are less . Just play with it . Feel for heat in head stock around bearing area . If it gets hot loosen up some . Those bearings will last the life of the machine . Longer than you will live . No big deal. These little machines are not high precision . But will do all you are ever capable of.

                      Thanks Lane.

                      A simple solution to a simple problem on a simple machine done easily.

                      Lane's "rule of thumb" is as good as it it gets.

                      Its also and excellent reason to run your machine up to temperature before using it - plus it gives all the bearings and working surfaces a good "work-through" and lubrication before applying a cutting load to them.

                      The principal is not a lot different at all - if any - from adjusting the bearing "cones" on a bicycle or the bearings in a car (non-driving) wheel or trailer wheels.

                      This is a classic case of looking for a "difficult" solution to what is really a simple matter and a simple "fix".

                      A look at the manufacturers hand-book/manual will be a good start (or a manual for a similar machine).


                      • #12
                        Manuals seem to be very hard to find. I have been checking around without success. I understand this model was sold in you your neck of the woods. The only one I have seen referenced on the net was for sale a couple of years ago in NZ. My manual is some where around my place but to date is still elusive.

                        They were for sale in the later 70's early 80's.
                        If you know where a manual is it would be appreciated.


                        • #13
                          That's a Bower ball bearing made in Japan the "205" in its envelope designation. I don't see the prefixes and suffixes normally found on precision grade bearings but I understand lately that bearings are supplied with this information only on the packaging. The only way to determne of this particuar bearing is a precision grade is to open it up enough to see if it's marked with eccentricity burnishes. I don't know if this is a geared headstock or step pulley but I'll procede as id it was geared.

                          The photo shows the rear spindle bearing on the index end of the headstock? Have you examined the whole spindle inside the headstock? The front bearing may duplexed and its preload is set with shims or spacers between the races. The outer races are held in compression with the spindle retainer visible behind the spindle nose and the inner races with a bearing nut on the spindle itself. Look for a bearing nut assocated with the front spindle bearing and the spindle gear. If this nut has backed off for some reason you'll have to snug it up and re-set the tab in the lock washer. Snugging up the rear bearing nut may have no effect if the rear bearing functions as a "float bearing".

                          Rant time:

                          There is so much utter BS and damn fool advice circulating on the topic of spindle bearings it's amost hopeless for the bearing noob to differentiate good advise from bad. The lesser fora seem to attract shade tree grade mechanics no better than yokels full of tales how they use trailer bearings ect as spindle bearings and "it worked just fine" - until you inspect a part they made.

                          I know my stuff. I've worked on spindles, compiled bearing course materials, taught classes, and toured spindle shops and interviewed their experts. I was on a NavSea technical board concerned with electing and grading equipment bearings for submarine noise reduction. Machine tool spindles do NOT contain inexpensive bearings. The single most critical attribute for a spindle is the quality of its axis of rotation. The bearing grade has been selected by the design engneer as the minimum necesary for the machine to perform to specifications.

                          Even though a spindle bearing may have the same envelope designation as a wheel bearing you buy at the auto parts store its precision grade is determined by its component parts selected from the production line, inspected, re-worked, graded, and assembled with special attention to the quality of the axis of rotation, the accuracy of their TIR and the squareness of the shoulders to the axis of rotation etc. Also they may be selected in pairs with specific race offsets to assemble as matched pairs for preload, concentricity error, and marked for the eccentricity highpoint.

                          The quality of a spindle i, among other things, dependent on the accuracy of the axis it generates. All spindles no matter how accurately made exhibit aome error. A spindle containing rolling element bearings will exhibit the irregularities and cyclic errors expected of them. Outer race out of round, inner race out of round and eccentricity, rolling element (ball or roller) out of round and size distribution. The result instrumented and displayed on a polar chart with a radial exaggeration of say 50,000 to 1 shows axis error as what I call a "potato shape" with a wiggly outline - the sum of the many error sources in the bearings and spindle.

                          The net size of this potato axis error in a good machine tool spindle is 20 to 40 millionths - well within reach of grade 7 angular contact bearings and an accurately made spindle. In a jig boring machine the axis error needs to be about 1/10 of this and the spindle bearings are specially asembled just for this service and cost astronomically.

                          A plain vanilla engine lathe spindle still needs to make round diameters whose roundness error is 1/4 to 1/10 the minimum size tolerance anticpated. In a Monarch ee or equivalent thi error might be 20 mllionth. A general purposed engine lathe 80 millionths. I have no figures of inspetion experience with import consumer grade shop machinery but I wouldn't set my sights too high.

                          OK Rant off.

                          Lane offers the best advise. Run the bearings working in gradual steps up to the highest speed. Run it at high speed for about 20 mnutes. Look for about 20 degrees F temperature rise over ambient. Adjust accordingly. Even the best and most sophisticated spindle shops use this technique or something very simlar for final acceptance.

                          As for lubrication, most ball and roller bearings need only a seep of oil to lubricate the cages and provide the molecules thick boundry film needed to mitigate the inevitable scrub present in rolling element bearings. Very high speed bearings were once lubricated with open cycle oil mist systems but now high adhesion greases are doing the same job. The 205 bearing in the photo shows traces of grease. I wouldn't mess with it unless it started making noise.
                          Last edited by Forrest Addy; 12-12-2010, 05:11 AM.


                          • #14
                            I am surprised it does not have Gamet bearings in it, with it being a colchester and all..

                            All I will add is this.... When tightening them spin the spindle at the same time to seat the bearing properly.....

                            Upon startup do not start in top speed... Spin it at a low speed for half an hour to let the bearing settle in again...

                            I am wondering if someone has been into that headstock before...Japanese bearings in a British lathe? I would have expected hoffmans or RHP or even a brit made Timken...
                            Precision takes time.


                            • #15
                              That's not a Colchester, RC. It's an Asian made Myford look-alike.