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  1. #1
    Join Date
    Apr 2012
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    Adelaide
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    Default Hercus/Bagear bar-bed spindle centre

    Hi,

    I've recently started cleaning up a Hercus/Bagear bar-bed hobby lathe.

    The lathe belonged to my father, who died a couple of years ago, and before that belonged to his father. We all lived in South Australia, so the lathe would have been purchased from McPherson's in Adelaide.

    The lathe carries no markings at all, other than the plate on the motor.

    It is virtually identical to the last two pictures here: Page Title although the bed appears to be a little longer. It has the back gears and compound rest options.

    My question is regarding the headstock spindle. Everything I have read on these lathes (and there isn't much around) says they have a 0.75" x 10 TPI spindle and accept a number 1 morse taper.

    This lathe has a 1" x 10 TPI spindle. The entrance diameter of the spindle measures 16.45 or 16.46mm, so 0.647" or 0.648". An MT1 lathe centre is too small. An MT2 centre goes in less than half way and can go no further. It is so far out that there is no way it would be safe to spin up.

    Does anybody know what sort of lathe centre I might need? I had a quick look at some tables for Brown & Sharpe and Jarno tapers, but nothing stands out.

    It is definitely meant to accept a centre of some sort, as the lathe came with a face plate and dog in addition to the 3-jaw chuck. The other end of the spindle is about 3/8", in keeping with the available literature.

    Unfortunately I have no background in machining. I work in IT by day, and am having to work things out as I go along. Being a child of the metric system also slows things down a little ;-)

    Any help would be greatly appreciated.

    Thanks.

  2. #2
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    Default

    Hard to guess what it might be.
    Are you able to measure the length of the taper in the spindle.
    Can you measure the diameter of the inner end of the taper.
    As you look down the bore of the spindle from the chuck end is there any noticeable step at the end of the taper.

  3. #3
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    Default

    I've had a look down the spindle. There is no noticeable step inside, but there is a noticeable difference in the machining where the taper appears to end and the spindle bore continues on. The tapered section is very smooth, whereas the rest of the bore is a bit rough looking.

    The other end of the spindle is actually a little over 0.5", not 3/8"'s as I stated previously.

    I tried to put some some firm-joint inside calipers down and get a reading. That came out at about 0.57".

    The depth appears to be about 2.57".

    Using 0.64" as the reading for the large end of the taper, that gives a cone angle of 1.56 degrees.

    Those figures don't match any chart, but a #5 jarno taper almost matches at 0.62"/0.50"/2.5". I was using some cheap digital calipers to take the readings.

  4. #4
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    Default

    I would be inclined to still think it could be a 2 morse.

    Dont concern yourself too much that the taper may not appear to go in all the way.

    The inside dimension is very close to the small size of the morse,as it stands with your measurement it is only .002" out.

    The spindle end as your say is smaller than a standard morse by .052".

    This is not really a problem.

    What you can try is putting some form of marking medium on a morse taper 2 and seeing how much mark you get in the bore or put the medium in the bore and see what you get on the taper.

    If you wanted you could also turn down an old morse taper 2 drill shank to your .648" and see how it fits.

    What did you want to run in the spindle.

  5. #5
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    Hi andrew,
    Try some research on a one and a half morse taper. I have heard of them but never seen one.

    Phil

  6. #6
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    Default

    Pipeclay:

    I've had another look, and you may be right. The #2 centre sticks out a long way, but there seems to be a decent friction fit for the amount that it does go in. There's no real side-to-side play I can feel.

    It still seems to stick out way too far though. I'm wondering if originally there was some kind of open-ended #2 sleeve that a #1 centre went into.

    Here is a picture of the #2 centre installed, and another of the centre next to the spindle showing how much of the centre is in contact with the spindle:

    http://www.users.on.net/~acatford/spindle1.JPG
    http://www.users.on.net/~acatford/spindle2.JPG

    The bent tail lathe dog I have couldn't possibly reach the faceplate from the work piece with the centre I've got. That said, I did some reading and it looks like you can use a straight lathe dog and drive it with a bolt coming off the face plate.


    Steamwhisperer:

    Thanks for that. I'll see what I can dig up. I think the only mention I've seen of a half-size morse taper previously was a 4.5(?)


    It's not a huge deal at the moment. I've still got a lot to learn, so it will probably be a while before I need to do any work between centres.

  7. #7
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    Hi Andrew,
    I just looked up my book and it says that Morse, Brown and Sharpe and Jarno are used in lathe spindles. There is also modified Morse which is longer than standard but the same taper and a Reed which is a short Jarno. Some manufacturers had their own special tapers as well.

    Phil

  8. #8
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    The angle of the taper is in most cases more critical than the length.

    In this case if the 2 is correct and a standard 2 centre protruding longer than your comfortable with you could allways make your own,just make it to suit your bore sizes.

    If turning between centres is what you intend using the centre for you may be better off just chucking a piece of material and turning a 60 degree point and let your dog drive off the chuck.

    If you want to use a centre instead just remember that most of the loading if not all will be pushing the centre into the spindle.

    The only real concerns you may have in using the standard centre sticking out of the spindle so far could be ridgidity/vibration and the length of work piece,the length of the drive dog can be altered either by welding or drill and tap to extend.

  9. #9
    Join Date
    Apr 2012
    Location
    Adelaide
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    Default

    That makes sense, thanks.

    I guess it's also worth remembering that this is an old and small hobby lathe. It was never designed to be super precise or to turn particularly long or large items.

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