Fixing an old lathe with spindle "droop"

Discussion in 'Machine Modifications' started by nurd77777, Dec 4, 2019 at 2:58 PM.

Help Support HMEM by donating:

  1. Dec 4, 2019 at 2:58 PM #1

    nurd77777

    nurd77777

    nurd77777

    Member

    Joined:
    Mar 10, 2015
    Messages:
    8
    Likes Received:
    0
    Hi Machinists I have had an old lathe and put up with it for so long. Its cast iron and has cast iron bearings which are so worn. Looked at molding some more bearings from aluminium with some tin mixed in but this seems like a lot of messing about. When u haven't got a lathe u cannot do any machining. Just today I looked at adjustable bearing sleeves to be used with tapered roller bearings. Could this be the answer ? There does not seem to be many specifications available so it would be difficult to specify what to order. Anyone have any experience ?
     

    Attached Files:

  2. Dec 4, 2019 at 3:49 PM #2

    Gordon

    Gordon

    Gordon

    Well-Known Member

    Joined:
    Jan 4, 2011
    Messages:
    600
    Likes Received:
    75
    You could just put in some bronze bushings if you have any way to rebore the mount. The lathe looks small enough that perhaps someone could do it on a mill or a larger lathe.
     
  3. Dec 4, 2019 at 4:22 PM #3

    goldstar31

    goldstar31

    goldstar31

    Well-Known Member

    Joined:
    Feb 20, 2010
    Messages:
    2,313
    Likes Received:
    511
    Gender:
    Male
    Occupation:
    Haggis Breeder
    Location:
    Twixt Tyne and Tees
    Sadly your photos are not clear enough for my poor eyes with macular degeneration.
    So some guessing is necessary . You say that you have cast iron bearings so are these the split bearings which have a single tightening bolt? If so I would caution you not to do any 'adjusting' as you could crack them.

    You could line bore but the odds are that the bed will be worn some 6 inches from the spindle/ chuck.
    To cure the bed wear, it could be Blancharded fairly cheaply and the ways built up with Devcon or the equivalent.
    Again, I suspect the spindle will be somewhat worn. Maybe it could be built up with Devcon or better built up with hard chroming. Then, I would consider tackling the worn headstock bearings- possibly with Devcon.

    Suffice to say, I've done up a couple or more Myfords.

    It all depends on what you are prepared to spend in money and obviously time. One can reach a point when it is better to buy a newer lathe.
     
  4. Dec 4, 2019 at 8:22 PM #4

    gunner312

    gunner312

    gunner312

    gunner312 HMEM Supporter

    Joined:
    Jun 19, 2009
    Messages:
    27
    Likes Received:
    4
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Belfair, WA
    It appears to me that the bearing housings are part of the bed. I would set it up on my mill and bore the bearings oversize and put/cast in a set of babbit bearings or even a set of bearings from an automobile crankshaft. As a last resort, I'd mill off the bearing housings and install a set of pillow block bearings at the present center height and make a new spindle to fit them with thread to fit the lathe chuck(s) I have. Too bad you aren't here in the US. I'd be more than Happy to help out. My machinery is large enough to handle the job. You could also make a cast iron bearing and bore the present bearing housings to fit them or vice-versa. I have some Oil-Lite bearing material that would also make a bearing for that size lathe.
     
  5. Dec 5, 2019 at 7:14 PM #5

    nurd77777

    nurd77777

    nurd77777

    Member

    Joined:
    Mar 10, 2015
    Messages:
    8
    Likes Received:
    0
    Thanks all ,I have enclosed a better view of the split bearing they sit in a square housing which is only 45mm wide and the shaft is 33mm so there is no room for a roller bearing. I think the best bet would be to cast some more bearings like the originals and line bore them in place. Dave Gingery did it on his lathe. I could use aluminium with up to 20% tin. We have low lead solder which is mostly tin over here. Its not much use for electronics (it grows whiskers) . Babit metal would be a possibility. I could cast two round billots then square them off to fit in bearing mountings on the mill. Then I could fabricate a boring bar if I can find a good straight rod. This would run between two cast iron bearings. (I have lots of soft cast iron but not big enough for these lathe bearings). The boring bar would be advanced against the bed which is a very solid wide piece of cast iron. Oh I forgot to say the bearings would be split once they had been line bored to allow for wear/testing etc. Sometimes it hard to determine the next course or action that's where friends come in. Regards Keith
     

    Attached Files:

  6. Dec 5, 2019 at 7:57 PM #6

    gunner312

    gunner312

    gunner312

    gunner312 HMEM Supporter

    Joined:
    Jun 19, 2009
    Messages:
    27
    Likes Received:
    4
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Belfair, WA
    Looking at your Bearings, I see that they are a split bearing with the top half squared or perhaps it's the bottom half that is squared, doesn't matter, it's there to keep the bearing from spinning. So, What I would do in your case is mill the split and re-cut (bore) the bearings to fit the spindle bearing surface.

    Then mill the bearing top clamp/mount to fit the new bearing height. re-install and Bobs yer Uncle as my friend from Australia says.

    The bearing center height stays (almost) the same because you haven't changed the OD of the bottom bearing and the top bearing is held in place by the original fitting.
     
  7. Dec 5, 2019 at 11:44 PM #7

    nurd77777

    nurd77777

    nurd77777

    Member

    Joined:
    Mar 10, 2015
    Messages:
    8
    Likes Received:
    0
    Hi Gunner The bearing in the pic is the top half. The bottom one is worn as you would expect from the weight of the chuck so I would be lowering the spindle if I recut the existing bearings. In the past I have damaged the bottom bearing trying to get it out (to change them round and get round the droop) , somebody mentioned they are fragile. The housing is square all the way round and I could cast some aly/tin cylinders and mill them to suit the housings. Then have a boring bar driven from the tool post with another bearing on the back of the headstock and get as near to the spindle journal dia. Then split the bearings with a hack saw blue them etc and scrape. The lathe originally was a capstan and hardly any spindle height I had difficulty in making cross slides for it. I do not expect to do all this soon but need to sort out a modus operandi first. Cannot help but think there must be many people with similar problems. Thank-you again see you on this forum.
    Keith
     
  8. Dec 6, 2019 at 12:22 AM #8

    mfrick

    mfrick

    mfrick

    Active Member

    Joined:
    May 5, 2015
    Messages:
    37
    Likes Received:
    7
    Well I have read the post and here is what I have done. First I have rebuilt lost of lathes with bronze bearings, the fix is simple and yet time consuming. You start with some 660 bearing bronze and split into halves with slitting saw then you soft solider the two halves back together. Before you machine the bearings you need to check the spindle and if the journals are tapered and or not round they need to be machined then polished, you then machine the new bearings to fit once done heat break apart clean up surfaces and install into head stock, you then install the spindle you will have to blue and scrap bearings and put oil passage in you may have to shim the caps. once done your ready to go. Good luck with your project.
    MF
     
  9. Dec 6, 2019 at 12:29 AM #9

    mfrick

    mfrick

    mfrick

    Active Member

    Joined:
    May 5, 2015
    Messages:
    37
    Likes Received:
    7
    Well I have read the post and here is what I have done. First I have rebuilt lost of lathes with bronze bearings, the fix is simple and yet time consuming. You start with some 660 bearing bronze and split into halves with slitting saw then you soft solider the two halves back together. Before you machine the bearings you need to check the spindle and if the journals are tapered and or not round they need to be machined then polished, you then machine the new bearings to fit once done heat break apart clean up surfaces and install into head stock, you then install the spindle you will have to blue and scrap bearings and put oil passage in you may have to shim the caps. once done your ready to go. Good luck with your project.
    MF
     
  10. Dec 6, 2019 at 11:06 AM #10

    nurd77777

    nurd77777

    nurd77777

    Member

    Joined:
    Mar 10, 2015
    Messages:
    8
    Likes Received:
    0
    Hi mfrick Thanks fer the info. An operation like this is always going to be daunting. I have just ordered some tubing to make a boring bar will have m12 on the inside to lock the cutter in place. i looked at the Gingery method of boring out bearings. I will not be entirely without machines when I take the lathe to bits, I have a small mill.
    Regards Keith
     

Share This Page