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Messaing around with the spindle bearings in my lathe!

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  • Messaing around with the spindle bearings in my lathe!

    Sorry about the typo in the title!

    My little Adept lathe as received:-


    DSCN0294 by aardvark_akubra, on Flickr
    It looks good but the bearing in the head are really, really slack.


    The bearings are simply borings in the casting so with nothing to loose I tried a little bodge, just because I could!

    IMGP9177 by aardvark_akubra, on Flickr
    First off strip the lathe (that took 45 seconds!) then clean the head bearings and heat with the heat gun.




    Now I am putting solder in the bearings.
    IMGP9178 by aardvark_akubra, on Flickr
    You might have heard that cast iron cant be soldered, well, it cant be soldered easily but it can be done and one of the methods is to rub the surface with copper while applying the solder. While the heat guns keeps the metal hot I added solder via a little soldering iron giving the surface a generous rub as I did so. Eventually most of the bores showed solder adhering to them. Sorry, no picture of that my camera is not good enough to 'see' inside there.
    Last edited by The Artful Bodger; 03-25-2011, 01:14 AM.

  • #2
    Now I am going to trim the inside of the bores, I realised the drill was not going to be such a good idea and eventually carefully trimmed it out by hand.

    IMGP9179 by aardvark_akubra, on Flickr

    The bores felt 'good' but not perfect, so I made up a rig to give the little lathe a try out!

    IMGP9191 by aardvark_akubra, on Flickr


    There we have it folks, a little tapered pin turned up on this tiny lathe!

    IMGP9193 by aardvark_akubra, on Flickr


    Now I need to know how to carefully bore out the headstock to take bushes of some kind. I have what I think are 'oilite' bushes, they are bronzy looking and have a distinctly oily look about them. Any comments on using these bushes anyone?

    Comment


    • #3
      I'm not sure how long the solder will last in there.

      There's a series of somebody line boring a plain bearing SB9 and fitting bushings to it. That may give you some ideas anyway. I think it was on PM IIRC

      Pete

      Edit: Found it! Not sure, but may be helpful http://www.practicalmachinist.com/vb...dstock-146690/

      Comment


      • #4
        the casting has a split and a bolt in it, Isent that for tightening the bearings?
        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

        Comment


        • #5
          Originally posted by Black_Moons
          the casting has a split and a bolt in it, Isent that for tightening the bearings?
          Yes, but on this type of lathe tightening those down is very likely to snap the casting. That has already been done by someone in the past and a brazed repair.

          Comment


          • #6
            Some potable water solders make a fair substitute for Babbitt metal. It ain't perfect but it's acceptable.

            Comment


            • #7
              Since the original bearings are just bored in the cast, your options are to bore them out large enough for a thin-walled bushing, or maybe you can get away with a two piece clamshell bearing, which I think should let you get away with the least amount of 'over boring'. I wonder if you can buy babbit in sheet form and roll your own to fit- or some other suitable sheet material such as silver (only partially kidding about this). Oilite is pre-oiled of course, so you wouldn't have to lube as often, but with any bearing shell material you'd have to supply constant lubing.

              If you set up a constant lube system, you could even use aluminum for the bearing shells. Maybe check out what used to be done in aero engines as far as bearing material.

              My motorcycle has steel shafts running directly in machined aluminum bores, and I think a lot of them were like that.

              Another thing to consider is a hydrodynamic type of bearing, where the lube circulates by virtue of the shaft turning. Many hard drives these days are made with this type of bearing. I have one in front of me right now, apart, and I can spin the disc with my fingers. Spin it one way, it glides along for a bit before it stops. Spin it the other way, it doesn't want to go. Shaft rotation forces an oil wedge to form and keeps the shaft from direct contact with the bearing material. If you rolled your own shells, you could create the oil grooves beforehand to create this action. Miniature ball bearings are so cheap these days that they would be used exclusively for hard drives, except they don't run as smoothly as plain bearings with this oil-wedge technology.

              I think this is well worth looking into, since with some care you can make these at home. What are the bearing surfaces on the spindle like- in good shape or ?

              As far as boring what you have, and in a perfect alignment, I'd be tempted to use the tailstock to control one end of a straight shaft and the inboard headstock bearing to control the other end. Careful measuring, and using the carriage should be able to tell you whether the shaft being held this way is parallel- on other words if you actually turned diameters on it, would they show a taper or not. If you can get an alignment on the tailstock to make this true, then the shaft can be held in perfect position to bore out the left end bearing. This would be a lot of fooling around to get to be able to re-size both bores, but I think it could be done.

              Another way might be to make two identical holders that fit the ways, each being bored with tooling in the chuck (the lathe would have to be usable for this operation). If both holders are machined in the same spot on the bed, their bores should line up exactly parallel to the spindle axis. They may not be exactly on axis, but they should be parallel. Then they can be used to carry a straight shaft which would carry a boring bit on the end of it, micro-adjustable of course. With either of these scenarios, you'd have to motorize the shaft to spin the boring bit, plus be able to move the shaft along in a well controlled manner.

              Just throwing some thoughts out there.
              I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

              Comment


              • #8
                Bodger,

                QUOTE: "Now I need to know how to carefully bore out the headstock to take bushes of some kind."

                The easiest way if the height of the Adept spindle will permit it is to mount the Adept on the cross slide of your bigger lathe and use a between centres boring bar - a smaller version of the set-up shown in the third photo here:
                http://www.lathes.co.uk/drummond/page3.html

                The workpiece is fed over the boring bar using the lathe's normal power feed.

                Even with the small diameter of the boring bar which would be required you can get quite good results using light cuts. You would have to work out some system of measuring the amount of tool stick-out from the boring bar to adjust for each cut - often done using a dial indicator mounted on a suitable bracket. Note that the boring bar effective overall length will have to be double the distance between the outer ends of the headstock bearings, and the tool in the middle of the bar.

                Alternatively, if you have a boring head which can be mounted in the headstock spindle, this will work too.

                An interesting variation of this is described by electrosteam in post #4 here:
                http://www.woodworkforums.com/f65/us...ng-bar-129635/

                where he says:

                QUOTE: "Recently, cannot remember where, I saw reference to a between centres boring bar with a boring head in the spindle holding the headstock end of the boring bar.

                The boring head is set on centre initially, the job rough bored with normal tool adjustment on the boring bar, then the boring head adjusted for fine tool trimming.
                With a good boring head, you can dial-up the required amount of cut.

                The headstock end of the boring bar moves in an orbital motion, but still circular."

                Since the tool is in the middle of the boring bar, the amount of tool movement would be about half the amount of offset applied to rhe boring head.

                franco
                Last edited by franco; 03-25-2011, 02:36 AM.

                Comment


                • #9
                  Darryl, the most easily available sheet materials are brass and copper, are either of these suitable as a bearing material?

                  The spindle is a simple 3/8" shaft and appears in good condition, obviously it would be easy enough to make another of these. The one I have is not original which would have had a Morse taper.

                  One of my options is to bore for a larger diameter spindle, a 10mm spindle is only .475mm oversize so thats one fairly easy option and might be good for another 60 years!

                  Thanks for the pointer to hydrodynamic bearings as that looks quite interesting even if I dont wind up using it for this project.

                  Alignment is a concern for boring and your idea of the two holders is a good one, fortunately the tail stock has the same bore as the head stock so thats could be useful. What will be difficult for boring is getting the bored size right as 3/8" is rather small to my mind!

                  Thanks for your comments and advice.

                  Comment


                  • #10
                    Thanks Franco, that 'orbital' boring bar is an interesting concept. I will have to think how I could use that.

                    Comment


                    • #11
                      Copper, bad bearing material. Brass, so-so.

                      I would bore and hone to the 10mm like you said. And get some TGP rod for the spindle. The Artisan lathe I have uses plain bearing. Steel running on cast iron. Works fine.

                      Comment


                      • #12
                        Oilite: the only thing I have read about this, in the "take care" department, is to use really sharp tooling as you don't want to "smear" the surface. Supposedly "smearing" can effect the movement of the oil (has to do with the porosity of the material)

                        Comment


                        • #13
                          Spindle Bearings on your lathe

                          I have a couple of older lathes that have Oilite Flanged bushings on the spindles and they work fine. They have oil cups over each one and I oil those areas every time I use them.

                          Ray
                          Ray
                          Central Texas

                          Comment


                          • #14
                            Artful........

                            I don't know about over there, but in the US, leaded solders are illegal for water pipe usage (we use a lot of copper pipe).

                            As Forrest mentions, for water pipe in the US there are considerably harder solders which are tin with silver and antimony (yeah, don't ask). I have successfully used them as a "babbit" material.

                            Dunno who told you that CI can't be soldered, but they didn't know very much, must be a "book larnin only" type....... I've soldered to CI with soft and also water-pipe solders, it works fine if any oil is burned out of the iron first....
                            1601

                            Keep eye on ball.
                            Hashim Khan

                            Comment


                            • #15
                              Have a Super Adept that was given to me by the guy across the road ..

                              Spindle bearings are trashed because he ran it with a 6000 rpm motor and no countershaft .

                              must have buggered those spindle bearings up in ten Min's ..

                              Th rest of the lathe has only had ten Min's use !!!!!..its as new with no wear on any other part.

                              was trying to figure out weather i could sell it ..on ebay in this condition ..
                              weather it would be better to sort it out and fix the bearing problem
                              and sell on ebay

                              or to make a countershaft for it ..get a another motor ..and sell it on ebay ..

                              see that "Th" up there...i cant correct it ..without words moving up against it ..this happens frequently in this forum ..no other

                              anyone know how to sort this word shuffle out ..makes me look crap


                              all the best.markj

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