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  1. #16
    Join Date
    May 2009
    Location
    Hobart, Tasmania
    Posts
    21

    Default

    The bearings are class 3 timken roller bearings and will be very expensive to replace. I'd be surprised if they need replacing.. I'd machine the backplate off just like pipeclay said. Just turn it like it was any other job. It will most likely be cast iron, but possibly steel. Almost certainly won't be hardened.

    Please don't use pipe-wrench like tools, they'll just damage things. The clamp I showed can be tightened as hard as you like and will grip like hell and not damage anything.

    I would try heat or penetrating oil. Unless there is a locking pin it will undo, even if there is a hidden pin, it will shear which is probably better than stuffing up the spindle bearings.

    As mentioned it's a 2.5" (edit: actually 2 1/4") thread, pretty hefty. Any corrosion will have it on there pretty tight. Also any kind of crash could really lock the chuck on there. Get yourself some big long levers to apply lots of torque with more control.

    Craig

  2. #17
    Join Date
    Jun 2007
    Location
    sydney ( st marys )
    Age
    64
    Posts
    4,887

    Default

    If you are going to try heat , I would suggest you remove the chuck and place bolts or pins into the mounting holes in the back plate and then position a long lever of some description between the bolts or pins so that you can apply force to the back plate.

    When it comes to heating I would spot heat only to the backing plate about 1" from the spindle , if using oxy should only take a few minutes to get it cherry red , you need to apply force to your lever at the same time.You don't won't to get the sp8ndle as hot as the back plate, you may even consider placing a wet rag in the spindle to try and eliminate it getting to hot.

    Once it starts to move keep turning it until it is off.

    If heat does not work just machine the backing plate off until you get down to just above the spindle thread, if it the size I think the spindle OD is 1 1/2", so around 1 5/8" should be okay, you may even find that you can take it lower, you should then be able to try monkeys or stillsons on it to unscrew the remainder, when machining it off make sure you don't cut the register face behind the spindle thread.

  3. #18
    Join Date
    May 2009
    Location
    Hobart, Tasmania
    Posts
    21

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    I just went and measured my dummy spindle nose. Definitely 2.25" X 6tpi. Not 2.5" as I previously mentioned (apologies).

    Certainly don't turn it down to 1 5/8", or you may be turning fresh air!

    Craig

    Sent from my HUAWEI TAG-L22 using Tapatalk

  4. #19
    Join Date
    Jun 2011
    Location
    Australia east coast
    Age
    71
    Posts
    2,713

    Default

    Quote Originally Posted by craigmarshall View Post
    I just went and measured my dummy spindle nose. Definitely 2.25" X 6tpi. Not 2.5" as I previously mentioned (apologies).
    Pipeclay is probably thinking about the earlier Premo lathes, which were 1 1/2-8 threaded spindles. I made a new spindle for mine and went to 2 1/4-8 to match the nose on my Smith-Drum.

    Then I sold the Premo.....

    Agree with pipeclay with the addition that sometimes a hard shock gets things moving when a steady force won't. Smacking the end of a stiff bar with a BIG hammer *provided* the spindle is properly restrained and won't suffer damage may shift things. I think I used a hydraulic jack to break the faceplate free on the Smith-Drum when I first got it. I wasn't turning *that* off, it was 28" diameter cast iron.

    PDW

  5. #20
    Join Date
    May 2019
    Location
    Wollongong
    Posts
    9

    Default Jacking

    Quote Originally Posted by PDW View Post
    Pipeclay is probably thinking about the earlier Premo lathes, which were 1 1/2-8 threaded spindles. I made a new spindle for mine and went to 2 1/4-8 to match the nose on my Smith-Drum.

    Then I sold the Premo.....

    Agree with pipeclay with the addition that sometimes a hard shock gets things moving when a steady force won't. Smacking the end of a stiff bar with a BIG hammer *provided* the spindle is properly restrained and won't suffer damage may shift things. I think I used a hydraulic jack to break the faceplate free on the Smith-Drum when I first got it. I wasn't turning *that* off, it was 28" diameter cast iron.

    PDW


    How’d you jack it off (lol), jack between headstock and back if the backplate, spoke to a guy from lusink, he said the same thing, today I heated it and shocked it somthing fierce, and to no avail, it still won’t budge, may have to look into machining it off

  6. #21
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,129

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    Sounds like a lot of mucking around.
    I would weld a socket to it and hit it with a rattle gun while it is still hot from the weld.
    cheers, shed

  7. #22
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,129

    Default

    If think that would be a bit of a bush job then bolt a bit of plate to the backing plate with a large bolt welded in centre of that, disengauge your gear train and impact it.
    You like wont need any heat and any shock from the impact gun into your brgs would be far less that when doing an inerupted cut.
    Cheers, shed

  8. #23
    Join Date
    Jul 2008
    Location
    near Warragul, Victoria
    Posts
    3,718

    Default Heat

    Been through this with a vintage Holbrook lathe. Heat cool heat cool more the better. I shoved a wet rag down the spindle . This went on for days but it finally came free . Be patient very important. The repeated heating cooling cycles will do the job . I locked the spindle by inserting a chuck jaw between
    the headstock casing and a gear. Its all described in a thread on this forum...//metalworkforums.com/f65/t1967...Holbrook+stuck

  9. #24
    Join Date
    May 2019
    Location
    Wollongong
    Posts
    9

    Default thread direction

    Im at that point where im questioning everything, before i resort to machining it off, which way do i have to turn it to loosen it, would i have to turn it towards me(me being in a operational position) (left, looking at the headstock from the tail stock) or away from me (right, looking at the head stock from the tailstock).

    Cheers

  10. #25
    Join Date
    Jul 2016
    Location
    Melbourne
    Age
    35
    Posts
    1,522

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    Looking from the tailstock turn it counterclockwise (left).

  11. #26
    Join Date
    May 2019
    Location
    Wollongong
    Posts
    9

    Default

    Quote Originally Posted by ZAC1000 View Post
    Im at that point where im questioning everything, before i resort to machining it off, which way do i have to turn it to loosen it, would i have to turn it towards me(me being in a operational position) (left, looking at the headstock from the tail stock) or away from me (right, looking at the head stock from the tailstock).

    Cheers

    Ah okie, cheers, was goin that way anyways : /

  12. #27
    Join Date
    Jun 2020
    Location
    Bacchus Marsh, victoria
    Posts
    27

    Default

    My MK2 5.5 inch premo has a 1 3/4 inch shaft. Getting the chuck off was difficult, but I engaged the back gears and applied steady pressure to the chuck with a long bar and it came off. BUT it was fairly tight which I did not expect.
    Am rebuilding the lathe currently and will look at this tightness aspect when I attend to the headstock.
    The headstock alignment uses 4 adjustable screws in the bed. It should be fairly straightforward to align the headstock. Famous last words I hope NOT.
    rumpfy

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