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Bad bearings? Dah Lih circa 1976 Taiwanese

Discussion in 'QUESTIONS & ANSWERS (Get Help Fast Here!)' started by Ropata, Aug 9, 2017.

  1. Ropata

    Ropata New Zealand Active Member Active Member

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    That hex head on the taper index? Pretty sure no other fixings holding it. Tried a bit of heat. Might have to take it to an old Swiss machinist locally and see if he has any tricks.

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  2. mikey

    mikey Active User H-M Supporter-Premium

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    Do you have any large hex material laying around? You could bore to fit the cap and run a bolt through the side and into that screw hole on the side, then use a big wrench to apply more force. OR ... you can go see your friend. :)
     
  3. Ropata

    Ropata New Zealand Active Member Active Member

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    Mate, that is a good idea but I think I might struggle to find 120mm hex around here. I do have the big wrench though.

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  4. Ropata

    Ropata New Zealand Active Member Active Member

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    Those are not screw holes on the side, they are just holes for a pin wrench.

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  5. Bob Korves

    Bob Korves H-M Supporter - Premium Content H-M Supporter-Premium

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    +1 that it is probably a left hand thread.
     
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  6. 4gsr

    4gsr Global Moderator Staff Member H-M Supporter-Premium

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    Inspect that cap nut closely for the letters "LH". Gorton was real nice to do this. Of course after putting all effort into trying to break it loose, you happen to notice the letters LH. :confusion:

    Another thing you could do, if you have another mill available to you, is to either cut a set of flats or a slot for a big spanner wrench. That way you have better bearing and less likely to shear off a "claw" as you do with a pin. Still think it's left handed....:boxed in:
     
  7. Downwindtracker2

    Downwindtracker2 Canada Active User Active Member

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    A rather common problem with 6200 series bearings is having them get axial preload . It's usually having either the wrong length spacer, spacer being too short, or no spacer at all. They get a notchy feeling ! If there has to be a preload, it has to be radial. I would guess that the clown before you jammed the nut into the thread end. A new pin wrench and some heat would be how I would attack it. The over tightening is a killer on 6200s. While 6200 series bearing do take some thrust loading, they have a deep race, but they are a basically a radial bearing . On one machine, I solved that by giving the operator a much shorter wrench. On your application the top bearing should be floating, whether on the shaft or housing. Thermal expansion has to have some place to go. When guys say don't mill on a drill press, I laugh. On my drill press the bearings are 6200s. You should only mill, not drill ! My guess your mill/drill is just a beefed up drill press.
     
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  8. 4gsr

    4gsr Global Moderator Staff Member H-M Supporter-Premium

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    I don't think so. If it is, it's the first one I've seen with both a horizontal and vertical spindles on the mill.
    I highly doubt it has 6200 series bearing for spindle bearings in the lower end. More than likely 7200 series bearings, hopefully set properly at the factory. Unless someone has had this apart in the past and put the wrong bearings in the spindle. The upper bearing is more than likely a single 6200 series bearing, not two.
     
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  9. 4gsr

    4gsr Global Moderator Staff Member H-M Supporter-Premium

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    If all else fails, take measurements of the cap on the outside. Then set up in a lathe and machine the cap down enough that it does not contact the housing face and attempt to remove. Just have to make a new cap afterwards. Applying heat to the housing to get it to let go could distort things as well as set fire to the oil or grease inside the housing. 400-500 degree F should be okay and no higher!
     
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  10. Ropata

    Ropata New Zealand Active Member Active Member

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    I have turned up a sleeve and bored to just fit over the problem cap. I will drill and put pins in then weld on a long breaker bar. Hope this works.

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  11. Ropata

    Ropata New Zealand Active Member Active Member

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    Well, looks like I'll have to try heat.
    20170817_160520.jpg 20170817_160527.jpg 20170817_160607.jpg
     
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  12. Ropata

    Ropata New Zealand Active Member Active Member

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    Anyone have any idea what sort of maximum temperature I could get the quill up to before causing any damage?

    Sorry 4gsr, just seen you posted earlier about max temp.
     
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  13. Bob Korves

    Bob Korves H-M Supporter - Premium Content H-M Supporter-Premium

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    There are probably precision bearings in there, quite expen$ive. Do not overheat them. I would not heat them over 150 F.
     
  14. Ropata

    Ropata New Zealand Active Member Active Member

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    I'm trying to open it to get the bearings out for replacement but warping the quill I am worried about.
     
  15. Bob Korves

    Bob Korves H-M Supporter - Premium Content H-M Supporter-Premium

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    300F (?) Don't want to temper the spindle hardness, much less warp it.
     
  16. mikey

    mikey Active User H-M Supporter-Premium

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    Wow, that is on there!

    Before hitting it with a torch, I would consider welding a piece of hex stock in the middle of the yellow bar and trying an impact gun on that. If that failed then I would try a heat gun, and if that failed I would wrap the quill with a wet rag and try the torch.
     
  17. RandyM

    RandyM United States Global Moderator Staff Member H-M Supporter-Premium

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    Are you sure they are not left hand threads?
     
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  18. Ropata

    Ropata New Zealand Active Member Active Member

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    well l can't be 100% sure until It's off but I can't think of any reason why. I know a BP is right hand and someone mentioned one brand so far that is left. Can you think of any others that are left? Also I have wrenched pretty hard the other way too.
     
  19. Bob Korves

    Bob Korves H-M Supporter - Premium Content H-M Supporter-Premium

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    My Burke Millrite has a left hand quill bottom thread.
     
  20. Ropata

    Ropata New Zealand Active Member Active Member

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    Ok. I'll set up in the morning to give it a good crack the other way.

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